hypothesis meaning in criminal law

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HYPOTHESIS Definition & Legal Meaning

Definition & citations:.

A supposition, assumption, or theory; a theory set up by the prosecution,on a criminal trial, or by the defense, as an explanation of the facts in evidence,and a ground for inferring guilt or innocence, as the case may be, or asindicating a probable or possible motive for the crime.

This article contains general legal information but does not constitute professional legal advice for your particular situation. The Law Dictionary is not a law firm, and this page does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

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Nadine Anderson, Behavioral Sciences and Women's & Gender Studies Librarian

Strong Research Questions

A strong research question covers a well-defined and well-studied area of research. Strong research topics/questions are:

• clear and simple
• consistent with assignment requirements
• of interest to you

Developing Your Research Question

A broad topic has literally thousands of articles on it, and you won't be able to adequately cover it in your literature review. It will be far easier for you to research and write your literature review if you develop a strong, focused research question:

Do some exploratory research  on your topic idea, in your course textbook and class notes to identify specific issues, arguments, and analytical approaches in your research area and then identify possible relationships between them. 

Ask yourself questions about your research topic : What interests me about this topic? What have people said about it? What gaps, contradictions, or concerns arise as you learn more about it? What relationships are there between different aspects of the topic?

Write a research question that your hypothesis answers : Use the information from your exploratory research and your answers to questions about your broad topic and the area you've decided to explore to build a focused, clear, simple research question

Identify the key concepts of your research question : what concepts will you need to define and measure in a study to answer your research question? How will you operationally define these concepts into numbers that you can analyze?

Identify your variables:  Use your operational definitions to identify and list the independent and dependent variables for your research question. Identify possible confounding variables and the variables you would use to control for them.

Choose a current topic:  Develop a hypothesis for a research area about which articles are continuing to be published. Avoid defunct or little-known areas of research. 

Write about what interests you:  Professors want students to develop experiments in areas that they care about. If you're interested in the topic, it will be more fun for you to do your experiment and write up your research paper, and probably more fun for your professor to read it, too.

Ask your professor  for feedback on whether the hypothesis you develop is a good hypothesis, one that can be tested.

Picking Your Topic IS Research

Once you've picked a research topic for your paper, it isn't set in stone. It's just an idea that you will test and develop through exploratory research. This exploratory research may guide you into modifying your original idea for a research topic. Watch this video for more info:

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The Legal Concept of Evidence

The legal concept of evidence is neither static nor universal. Medieval understandings of evidence in the age of trial by ordeal would be quite alien to modern sensibilities (Ho 2003–2004) and there is no approach to evidence and proof that is shared by all legal systems of the world today. Even within Western legal traditions, there are significant differences between Anglo-American law and Continental European law (see Damaška 1973, 1975, 1992, 1994, 1997). This entry focuses on the modern concept of evidence that operates in the legal tradition to which Anglo-American law belongs. [ 1 ] It concentrates on evidence in relation to the proof of factual claims in law. [ 2 ]

It may seem obvious that there must be a legal concept of evidence that is distinguishable from the ordinary concept of evidence. After all, there are in law many special rules on what can or cannot be introduced as evidence in court, on how evidence is to be presented and the uses to which it may be put, on the strength or sufficiency of evidence needed to establish proof and so forth. But the law remains silent on some crucial matters. In resolving the factual disputes before the court, the jury or, at a bench trial, the judge has to rely on extra-legal principles. There have been academic attempts at systematic analysis of the operation of these principles in legal fact-finding (Wigmore 1937; Anderson, Schum, and Twining 2009). These principles, so it is claimed, are of a general nature. On the basis that the logic in “drawing inferences from evidence to test hypotheses and justify conclusions” is governed by the same principles across different disciplines (Twining and Hampsher-Monk 2003: 4), ambitious projects have been undertaken to develop a cross-disciplinary framework for the analysis of evidence (Schum 1994) and to construct an interdisciplinary “integrated science of evidence” (Dawid, Twining, and Vasilaki 2011; cf. Tillers 2008).

While evidential reasoning in law and in other contexts may share certain characteristics, there nevertheless remain aspects of the approach to evidence and proof that are distinctive to law (Rescher and Joynt 1959). Section 1 (“conceptions of evidence”) identifies different meanings of evidence in legal discourse. When lawyers talk about evidence, what is it that they are referring to? What is it that they have in mind? Section 2 (“conditions for receiving evidence”) approaches the concept of legal evidence from the angle of what counts as evidence in law. What are the conditions that the law imposes and must be met for something to be received by the court as evidence? Section 3 (“strength of evidence”) shifts the attention to the stage where the evidence has already been received by the court. Here the focus is on how the court weighs the evidence in reaching the verdict. In this connection, three properties of evidence will be discussed: probative value, sufficiency, and degree of completeness.

1. Conceptions of Evidence: What does Evidence Refer to in Law?

2.1.1 legal significance of relevance, 2.1.2 conceptions of logical relevance, 2.1.3 logical relevance versus legal relevance, 2.2 materiality and facts-in-issue, 2.3.1 admissibility and relevance, 2.3.2 admissibility or exclusionary rules, 3.1 probative value of specific items of evidence, 3.2.1 mathematical probability and the standards of proof, 3.2.2 objections to using mathematical probability to interpret standards of proof, 3.3 the weight of evidence as the degree of evidential completeness, other internet resources, related entries.

Stephen (1872: 3–4, 6–7) long ago noted that legal usage of the term “evidence” is ambiguous. It sometimes refers to that which is adduced by a party at the trial as a means of establishing factual claims. (“Adducing evidence” is the legal term for presenting or producing evidence in court for the purpose of establishing proof.) This meaning of evidence is reflected in the definitional section of the Indian Evidence Act (Stephen 1872: 149). [ 3 ] When lawyers use the term “evidence” in this way, they have in mind what epistemologists would think of as “objects of sensory evidence” (Haack 2004: 48). Evidence, in this sense, is divided conventionally into three main categories: [ 4 ] oral evidence (the testimony given in court by witnesses), documentary evidence (documents produced for inspection by the court), and “real evidence”; the first two are self-explanatory and the third captures things other than documents such as a knife allegedly used in committing a crime.

The term “evidence” can, secondly, refer to a proposition of fact that is established by evidence in the first sense. [ 5 ] This is sometimes called an “evidential fact”. That the accused was at or about the scene of the crime at the relevant time is evidence in the second sense of his possible involvement in the crime. But the accused’s presence must be proved by producing evidence in the first sense. For instance, the prosecution may call a witness to appear before the court and get him to testify that he saw the accused in the vicinity of the crime at the relevant time. Success in proving the presence of the accused (the evidential fact) will depend on the fact-finder’s assessment of the veracity of the witness and the reliability of his testimony. (The fact-finder is the person or body responsible for ascertaining where the truth lies on disputed questions of fact and in whom the power to decide on the verdict vests. The fact-finder is also called “trier of fact” or “judge of fact”. Fact-finding is the task of the jury or, for certain types of cases and in countries without a jury system, the judge.) Sometimes the evidential fact is directly accessible to the fact-finder. If the alleged knife used in committing the crime in question (a form of “real evidence”) is produced in court, the fact-finder can see for himself the shape of the knife; he does not need to learn of it through the testimony of an intermediary.

A third conception of evidence is an elaboration or extension of the second. On this conception, evidence is relational. A factual proposition (in Latin, factum probans ) is evidence in the third sense only if it can serve as a premise for drawing an inference (directly or indirectly) to a matter that is material to the case ( factum probandum ) (see section 2.2 below for the concept of materiality). The fact that the accused’s fingerprints were found in a room where something was stolen is evidence in the present sense because one can infer from this that he was in the room, and his presence in the room is evidence of his possible involvement in the theft. On the other hand, the fact that the accused’s favorite color is blue would, in the absence of highly unusual circumstances, be rejected as evidence of his guilt: ordinarily, what a person’s favorite color happens to be cannot serve as a premise for any reasonable inference towards his commission of a crime and, as such, it is irrelevant (see discussion of relevance in section 2.1 below). In the third sense of “evidence”, which conceives of evidence as a premise for a material inference, “irrelevant evidence” is an oxymoron: it is simply not evidence. Hence, this statement of Bentham (1825: 230): [ 6 ]

To say that testimony is not pertinent, is to say that it is foreign to the case, has no connection with it, and does not serve to prove the fact in question; in a word, it is to say, that it is not evidence.

There can be evidence in the first sense without evidence in the second or third sense. To pursue our illustration, suppose it emerges during cross-examination of the expert that his testimony of having found a finger-print match was a lie. Lawyers would describe this situation as one where the “evidence” (the testimony of the expert) fails to prove the fact that it was originally produced to prove and not that no “evidence” was adduced on the matter. Here “evidence” is used in the first sense—evidence as testimony—and the testimony remains in the court’s record whether it is believed or not. But lawyers would also say that, in the circumstances, there is no “evidence” that the accused was in the room, assuming that there was nothing apart from the discredited expert testimony of a fingerprint match to establish his presence there. Here, the expert’s testimony is shown to be false and fails to establish that the accused’s fingerprints were found in the room, and there is no (other) factual basis for believing that he was in the room. The factual premise from which an inference is sought to be drawn towards the accused’s guilt is not established.

Fourthly, the conditions for something to be received (or, in technical term “admitted”) as evidence at the trial are sometimes included in the legal concept of evidence. (These conditions are discussed in section 2 below.) On this conception, legal evidence is that which counts as evidence in law. Something may ordinarily be treated as evidence and yet be rejected by the court. Hearsay is often cited as an example. It is pointed out that reliance on hearsay is a commonplace in ordinary life. We frequently rely on hearsay in forming our factual beliefs. In contrast, “hearsay is not evidence” in legal proceedings (Stephen 1872: 4–5). As a general rule, the court will not rely on hearsay as a premise for an inference towards the truth of what is asserted. It will not allow a witness to testify in court that another person X (who is not brought before the court) said that p on a certain occasion (an out-of-court statement) for the purpose of proving that p .

In summary, at least four possible conceptions of legal evidence are in currency: as an object of sensory evidence, as a proposition of fact, as an inferential premise and as that which counts as evidence in law. The sense in which the term “evidence” is being used is seldom made explicit in legal discourse although the intended meaning will often be clear from the context.

2. Conditions for Receiving Evidence: What Counts as Evidence in Law?

This section picks up on the fourth conception of evidence. To recall, something will be accepted by the court as evidence—it is, to use Montrose’s term, receivable as evidence in legal proceedings—only if three basic conditions are satisfied: relevance , materiality, and admissibility (Montrose 1954). These three conditions of receivability are discussed in turn below.

2.1 Relevance

The concept of relevance plays a pivotal role in legal fact-finding. Thayer (1898: 266, 530) articulates its significance in terms of two foundational principles of the law of evidence: first, without exception, nothing which is not relevant may be received as evidence by the court and secondly, subject to many exceptions and qualifications, whatever is relevant is receivable as evidence by the court. Thayer’s view has been influential and finds expression in sources of law, for example, in Rule 402 of the Federal Rules of Evidence in the United States. [ 7 ] Thayer claims, and it is now widely accepted, that relevance is a “logical” and not a legal concept; in section 2.1.3 , we will examine this claim and the dissent expressed by Wigmore. Leaving aside the dissenting view for the moment, we will turn first to consider possible conceptions of relevance in the conventional sense of logical relevance.

Evidence may be adduced in legal proceedings to prove a fact only if the fact is relevant. Relevance is a relational concept. No fact is relevant in itself; it is relevant only in relation to another fact. The term “probable” is often used to describe this relation. We see two instances of this in the following well-known definitions. According to Stephen (1886: 2, emphasis added):

The word “relevant” means that any two facts to which it is applied are so related to each other that according to the common course of events one either taken by itself or in connection with other facts proves or renders probable the past, present, or future existence or non-existence of the other.

The second definition is contained in the United States’ Federal Rule of Evidence 401 which (in its restyled version) states that evidence is relevant if “it has a tendency to make a fact more or less probable than it would be without the evidence” (emphasis added). The word “probable” in these and other standard definitions is sometimes construed as carrying the mathematical meaning of probability. [ 8 ] In a leading article, Lempert gave this example to show how relevance turns on the likelihood ratio. The prosecution produces evidence that the perpetrator’s blood found at the scene of the crime is type A. The accused has the same blood type. Suppose fifty percent of the suspect population has type A blood. If the accused is in fact guilty, the probability that the blood found at the scene will be type A is 1.0. But if he is in fact innocent, the probability of finding type A blood at the scene is 0.5—that is, it matches the background probability of type A blood from the suspect population. The likelihood ratio is the ratio of the first probability to the second—1.0:0.5 or, more simply, 2:1. Evidence is considered relevant so long as the likelihood ratio is other than 1:1 (Lempert 1977). If the ratio is 1:1, that means that the probability of the evidence is the same whether the accused is guilty or innocent.

The conventional view is that relevance in law is a binary concept: evidence is either relevant or it is not. So long as the likelihood ratio is other than 1:1, the evidence is considered relevant. [ 9 ] However, the greater the likelihood ratio deviates from 1:1, the higher the so-called probative value of the evidence (that is, on one interpretation of probative value). We will take a closer look at probative value in section 3.1 below.

While the likelihood ratio may be useful as a heuristic device in analysing evidential reasoning, it is controversial as to whether it captures correctly the concept of relevance. In the first place, it is unclear that the term “probable” in the standard definitions of relevance was ever intended as a reference to mathematical probability. Some have argued that relevance should be understood broadly such that any evidence would count as relevant so long as it provides some reason in support of the conclusion that a proposition of fact material to the case is true or false (Pardo 2013: 576–577).

The mathematical conception of relevance has been disputed. At a trial, it is very common for the opposing sides to present competing accounts of events that share certain features. To use Allen’s example, the fact that the accused drove to a particular town on a particular day and time is consistent with the prosecution’s case that he was driving there to commit a murder and also with the defence’s case that he was driving there to visit his mother. This fact, being a common feature of both sides’ explanations of the material events, is as consistent with the hypothesis of guilt as with the hypothesis of innocence. On the likelihood ratio conception of relevance, this fact should be irrelevant and hence evidence of it should not be allowed to be adduced. But in such cases, the court will let the evidence in (Park et al. 2010: 10). The mathematical theory of relevance cannot account for this. (For critical discussion of this claim, see section 4.2 of the entry on legal probabilism .) It is argued that an alternative theory of relevance better fits legal practice and is thus to be preferred. On an explanatory conception of relevance, evidence is relevant if it is explained by or provides a reason for believing the particular explanation of the material events offered by the side adducing the evidence, and it remains relevant even where, as in our example, the evidence also supports or forms part of the explanation offered by the opponent (Pardo and Allen 2008: 241–2; Pardo 2013: 600).

One possible response to the above challenge to the likelihood ratio theory of relevance is to deny that it was ever meant to be the exclusive test of relevance. Evidence is relevant if the likelihood ratio is other than 1:1. But evidence may also be relevant on other grounds, such as when it provides for a richer narrative or helps the court in understanding other evidence. It is for these reasons that witnesses are routinely allowed to give their names and parties may present diagrams, charts and floor plans (so-called “demonstrative evidence”) at the trial (McCormick 2013: 995). The admission of evidence in the scenario painted by Allen above has been explained along a similar line (Park et al. 2010: 16).

The concept of relevance examined in the preceding section is commonly known as “logical relevance”. This is somewhat of a misnomer: “Relevance is not a matter of logic, but depends on matters of fact” (Haack 2004: 46). In our earlier example, the relevance of the fact that the accused has type A blood depends obviously on the state of the world. On the understanding that relevance is a probabilistic relation, it is tempting to think that in describing relevance as “logical”, one is subscribing to a logical theory of probability (cf. Franklin 2011). However, the term “logical relevance” was not originally coined with this connotation in mind. In the forensic context, “logic” is used loosely and refers to the stock of background beliefs or generalisations and the type of reasoning that judges and lawyers are fond of labelling as “commonsense” (MacCrimmon 2001–2002; Twining 2006: 334–335).

A key purpose of using the adjective “logical” is to flag the non-legal character of relevance. As Thayer (1898: 269) famously claimed, relevance “is an affair of logic and not of law.” This is not to say that relevance has no legal dimension. The law distinguishes between questions of law and questions of fact. An issue of relevance poses a question of law that is for the judge to decide and not the jury, and so far as relevance is defined in legal sources (for example, in Federal Rule of Evidence 401 mentioned above), the judge must pay heed to the legal definition. But legal definitions of relevance are invariably very broad. Relevance is said to be a logical, and non-legal, concept in the sense that in answering a question of relevance and in applying the definition of relevance, the judge has necessarily to rely on extra-legal resources and is not bound by legal precedents. Returning to Federal Rule of Evidence 401, it states generally that evidence is relevant if “it has a tendency to make a fact more or less probable than it would be without the evidence”. In deciding whether the evidence sought to be adduced does have this tendency, the judge has to look outside the law. Thayer was most insistent on this. As he put it, “[t]he law furnishes no test of relevancy. For this, it tacitly refers to logic and general experience” (Thayer 1898: 265). That the accused’s favorite color is blue is, barring extraordinary circumstances, irrelevant to the question of his intention to commit theft. It is not the law that tells us so but “logic and general experience”. On Thayer’s view, the law does not control or regulate the assessment of relevance; it assumes that judges are already in possession of the (commonsense) resources to undertake this assessment.

Wigmore adopts a different position. He argues, against Thayer, that relevance is a legal concept. There are two strands to his contention. The first is that for evidence to be relevant in law, “a generally higher degree of probative value” is required “than would be asked in ordinary reasoning”:

legal relevance denotes…something more than a minimum of probative value. Each single piece of evidence must have a plus value. (cf. Pattenden 1996–7: 373)

As Wigmore sees it, the requirement of “plus value” guards against the jury “being satisfied by matters of slight value, capable to being exaggerated by prejudice and hasty reasoning” (Wigmore 1983b: 969, cf. 1030–1031). Opponents of Wigmore acknowledge that there may be sound policy reasons for excluding evidence of low probative value. Receiving the evidence at the trial might raise a multiplicity of issues, incur too much time and expense, confuse the jurors or produce undue prejudice in their mind. When the judge excludes evidence for any of these reasons, and the judge has the discretion to do so in many countries, the evidence is excluded despite it being relevant (e.g., United States’ Federal Rule of Evidence 403). Relevance is a relation between facts and the aforesaid reasons for exclusion are extrinsic to that relation; they are grounded in considerations such as limitation of judicial resources and jury psychology. The notion of “plus value” confuses relevance with extraneous considerations (James 1941; Trautman 1952).

There is a second strand to Wigmore’s contention that relevance is a legal concept. Relevance is legal in the sense that the judge is bound by previously decided cases (“judicial precedents”) when he has to make a ruling on the relevance of a proposed item of evidence.

So long as Courts continue to declare…what their notions of logic are, just so long will there be rules of law which must be observed. (Wigmore 1983a: 691)

Wigmore cites in support the judgment of Cushing C.J. in State v LaPage where it was remarked:

[T]here are many instances in which the evidence of particular facts as bearing on particular issues has been so often the subject of discussion in courts of law, and so often ruled upon, that the united logic of a great many judges and lawyers may be said to furnish…the best evidence of what may be properly called common -sense, and thus to acquire the authority of law. (1876 57 N.H. 245 at 288 [Supreme Court, New Hampshire])

Wigmore’s position on relevance is strangely at odds with his strong stand against the judge being bound by judicial precedents in assessing the weight or credibility of evidence (Wigmore 1913). More importantly, the second strand of his argument also does not sit well with the first strand. If, as Wigmore contends, evidence must have a plus value to make it legally relevant, the court has to consider the probative value of the evidence and to weigh it against the amount of time and expense likely to be incurred in receiving the evidence, the availability of other evidence, the risk of the evidence misleading or confusing the trier of fact and so forth. Given that the assessment of plus value and, hence, legal relevance is so heavily contextual, it is difficult to see how a judicial precedent can be of much value in another case in determining a point of legal relevance (James 1941: 702).

We have just considered the first condition of receivability, namely, relevance. That fact A is relevant to fact B is not sufficient to make evidence of fact A receivable in court. In addition, B must be a “material” fact. The materiality of facts in a particular case is determined by the law applicable to that case. In a criminal prosecution, it depends on the law which defines the offence with which the accused is charged and at a civil trial, the law which sets out the elements of the legal claim that is being brought against the defendant (Wigmore 1983a, 15–19; Montrose 1954: 536–537).

Imagine that the accused is prosecuted for the crime of rape and the alleged victim’s behaviour (fact A ) increases the probability that she had consented to have sexual intercourse with the accused (fact B ). On the probabilistic theory of relevance that we have considered, A is relevant to B . Now suppose that the alleged victim is a minor. Under criminal law, it does not matter whether she had consented to the sexual intercourse. If B is of no legal consequence, the court will not allow evidence of A to be adduced for the purpose of proving B : the most obvious reason is that it is a waste of time to receive the evidence.

Not all material facts are necessarily in dispute. Suppose the plaintiff sues the defendant for breach of contract. Under the law of contract, to succeed in this action, the plaintiff must prove the following three elements: that there was a contract between the parties, that the defendant was in breach of the contract, and that the plaintiff had suffered loss as a result of that breach. The defendant may concede that there was a contract and that he was in breach of it but deny that the plaintiff had suffered any loss as a result of that breach. In such a situation, only the last of the material facts is disputed. Following Stephen’s terminology, a disputed material fact is called a “fact in issue” (Stephen 1872: 9).

The law does not allow evidence to be adduced to prove facts that are immaterial. Whether evidence may be adduced to prove a material fact may depend on whether the material fact is disputed; for instance, the requirement that it must be disputed exists under Rule 210 of the Evidence Code of California but not Rule 401 of the Federal Rules of Evidence in the United States. “Relevance” is often used in the broader sense that encompasses the concepts under discussion. Evidence is sometimes described as “irrelevant” not for the reason that no logical inference can be drawn to the proposition that is sought to be proved (in our example, A is strictly speaking relevant to B ) but because that proposition is not material or not disputed (in our example, B is not material). [ 10 ] This broader usage of the term “relevance”, though otherwise quite harmless, does not promote conceptual clarity because it runs together different concepts (see James 1941: 690–691; Trautman 1952: 386; Montrose 1954: 537).

2.3 Admissibility

A further condition must be satisfied for evidence to be received in legal proceedings. There are legal rules that prohibit evidence from being presented at a trial even though it is relevant to a factual proposition that is material and in issue. These rules render the evidence to which they apply “inadmissible” and require the judge to “exclude” it. Two prominent examples of such rules of admissibility or rules of exclusion are the rule against hearsay evidence and the rule against character evidence. This section considers the relation between the concept of relevance and the concept of admissibility. The next section ( section 2.3.2 ) discusses general arguments for and against exclusionary or admissibility rules.

Here, again, the terminology is imprecise. Admissibility and receivability are not clearly distinguished. It is common for irrelevant evidence, or evidence of an immaterial fact to be described as “inadmissible”. What this means is that the court will refuse to receive evidence if it is irrelevant or immaterial. But, importantly, the court also excludes evidence for reasons other than irrelevance and immateriality. For Montrose, there is merit in restricting the concept of “inadmissibility” to the exclusion of evidence based on those other reasons (Montrose 1954: 541–543). If evidence is rejected on the ground of irrelevance, it is, as Thayer (1898: 515) puts it, “the rule of reason that rejects it”; if evidence is rejected under an admissibility or exclusionary rule, the rejection is by force of law. The concepts of admissibility and materiality should also be kept apart. This is because admissibility or exclusionary rules serve purposes and rationales that are distinct from the law defining the crime or civil claim that is before the court and it is this law that determines the materiality of facts in the dispute.

Thayer (1898: 266, 530) was influential in his view that the law of evidence has no say on logical relevance and that its main business is in dealing with admissibility. If the evidence is logically irrelevant, it must for that reason be excluded. If the evidence is logically relevant, it will be received by the court unless the law—in the form of an exclusionary or admissibility rule—requires its exclusion. In this scheme, the concept of relevance and the concept of admissibility are distinct: indeed, admissibility rules presuppose the relevance of the evidence to which they apply.

Stephen appears to hold a different view, one in which the concept of admissibility is apparently absorbed by the concept of relevance. Take, for example, Stephen’s analysis of the rule that in general no evidence may be adduced to prove “statements as to facts made by persons not called as witnesses”, in short, hearsay (Stephen 1872: 122). As a general rule, no evidence may be given of hearsay because the law prohibits it. The question then arises as to the rationale for this prohibition. Stephen’s answer to this question is often taken to be that hearsay is not “relevant” and he is criticised for failing to see the difference between relevance and admissibility (Whitworth 1881: 3; Thayer 1898: 266–268; Pollock 1876, 1899; Wigmore 1983a: §12). His critics point out that hearsay has or can have probative value and evidence of hearsay is excluded despite or regardless of its relevance. On the generalisation that there is no smoke without fire, the fact that a person claimed that p in a statement made out-of-court does or can have a bearing on the probability that p , and p may be (logically relevant to) a material fact in the dispute.

Interestingly, Stephen seemed to have conceded as much. He acknowledged that a policeman or a lawyer engaged in preparing a case would be negligent if he were to shut his ears to hearsay. Hearsay is one of those facts that are “apparently relevant but not really so” (Stephen 1872: 122; see also Stephen 1886: xi). In claiming that hearsay is irrelevant, Stephen appears to be merely stating the effect of the law: the law requires that hearsay be treated as irrelevant. He offered a variety of justifications for excluding hearsay evidence: its admissibility would “present a great temptation to indolent judges to be satisfied with second-hand reports” and “open a wide door to fraud”, with the result that “[e]veryone would be at the mercy of people who might tell a lie, and whose evidence could neither be tested nor contradicted” (Stephen 1872: 124–125). For his detractors, these are reasons of policy and fairness and it disserves clarity to sneak such considerations into the concept of relevance.

Although there is force to the criticism that Stephen had unhelpfully conflated admissibility and relevance (understood as logical relevance), something can perhaps be said in his defence. Exclusionary rules or rules of admissibility—at any rate, many of them—are more accurately seen as excluding forms of reasoning rather than prohibiting proof of certain types of facts (McNamara 1986). This is certainly true of the hearsay rule. On one authoritative definition of the rule (decision of the Privy Council in Subramaniam v PP , (1956) 1 Weekly Law Reports 965), what it prohibits is the use of a hearsay statement to prove the truth of the facts asserted therein. [ 11 ] The objection is to the drawing of the inference that p from X ’s out-of-court statement that p where X is not available to be examined in court. But the court will allow the evidence of X ’s hearsay statement to be admitted—it will allow proof of the statement— where the purpose of adducing the evidence is to persuade the court that X did make the statement and this fact is relevant for some other purpose. For instance, it may be relevant as to the state of mind of the person hearing the statement, and his state of mind may be material to his defence of having acted under duress. Hence, two writers have commented that “there is no such thing as hearsay evidence , only hearsay uses ” (Roberts and Zuckerman 2010: 385).

Other admissibility rules are also more accurately seen as targeted at forms of reasoning and not types of facts. In the United States, Federal Rule of Evidence 404(a)(1) bars the use of evidence of a person’s character “to prove that on a particular occasion the person acted in accordance with the character” and Federal Rule of Evidence 404(b)(1) provides that evidence of a crime or wrong

is not admissible to prove a person’s character in order to show that on a particular occasion the person acted in accordance with the character.

It is doubtful that evidence of a person’s character and past behaviour can have no probabilistic bearing on his behaviour on a particular occasion; on a probabilistic conception of relevance, it is difficult to see why the evidence is not relevant. Even so, there may be policy, moral or other reasons for the law to prohibit certain uses of character evidence. In declaring a fact as irrelevant for a particular purpose, we are not necessarily saying or implying anything about probability. We may be expressing a normative judgment. For policy, moral or other reasons, the law takes the position that hearsay or the accused’s character or previous misconduct must not be used as the premise for a particular line of reasoning. The line of reasoning might be morally objectionable (“give a dog a bad name and hang him for it”) or it might be unfair to permit the drawing of the inference when the opponent was not given a fair opportunity to challenge it (as in the hearsay situation) (Ho 2008: chs. 5, 6). If we take a normative conception of relevance instead of a logical or probabilistic one, it is not an abuse of language to describe inadmissible evidence as irrelevant if what is meant is that the evidence ought not to be taken into account in a certain way.

On one historical account, admissibility or exclusionary rules are the product of the jury system where citizens untrained in assessing evidence sit as judges of fact. These rules came about because it was thought necessary to keep away from inexperienced jurors certain types of evidence that may mislead or be mishandled by them—for instance, evidence to which they are likely to give too much weight or that carries the risk of creating unfair prejudice in their minds (Thayer 1898; Wigmore 1935: 4–5). Epistemic paternalism is supposedly at play (Leiter 1997: 814–5; Allen and Leiter 2001: 1502). Subscription to this theory has generated pressure for the abolition of exclusionary rules with the decline of the jury system and the replacement of lay persons with professional judges as triers of fact. There is doubt as to the historical accuracy of this account; at any rate, it does not appear capable of explaining the growth of all exclusionary rules (Morgan 1936–37; Nance 1988: 278–294).

Even if the theory is right, it does not necessarily follow that exclusionary rules should be abolished once the jury system is removed. Judges may be as susceptible to the same cognitive and other failings as the jury and there may be the additional risk that judges may over-estimate their own cognitive and intellectual abilities in their professional domain. Hence, there remains a need for the constraints of legal rules (Schauer 2006: 185–193). But the efficacy of these rules in a non-jury system is questionable. The procedural reality is that judges will have to be exposed to the evidence in order to decide on its admissibility. Since a judge cannot realistically be expected to erase the evidence from his mind once he has decided to exclude it, there seems little point in excluding the evidence; we might as well let the evidence in and allow judge to give the evidence the probative value that it deserves (Mnookin 2006; Damaška 2006; cf. Ho 2008: 44–46).

Bentham was a strong critic of exclusionary rules. He was much in favour of “freedom of proof” understood as free access to information and the absence of formal rules that restrict such access (Twining 2006: 232, n 65). The direct object of legal procedure is the “rectitude of decision”, by which he means the correct application of substantive law to true findings of facts. The exclusion of relevant evidence—evidence capable of casting light on the truth—is detrimental to this end. Hence, no relevant evidence should be excluded; the only exceptions he would allow are where the evidence is superfluous or its production would involve preponderant delay, expense or vexation (Bentham 1827: Book IX; Bentham 1825: Book VII; Twining 1985: ch. 2). Bentham’s argument has been challenged on various fronts. It is said that he overvalued the pursuit of truth, undervalued procedural fairness and procedural rights, and placed too much faith in officials, underestimating the risk of abuse when they are given discretion unfettered by rules (Twining 1985: 70–71).

Even if we agree with Bentham that rectitude of decision is the aim of legal procedure and that achieving accuracy in fact-finding is necessary to attain this aim, it is not obvious that a rule-based approach to admissibility will undermine this aim in the long run. Schauer has defended exclusionary rules of evidence along a rule-consequentialist line. Having the triers of fact follow rules on certain matters instead of allowing them the discretion to exercise judgment on a case-by-case basis may produce the greatest number of favourable outcomes in the aggregate. It is in the nature of a formal rule that it has to be followed even when doing so might not serve the background reason for the rule. If hearsay evidence is thought to be generally unreliable, the interest of accuracy may be better served overall to require such evidence to be excluded without regard to its reliability in individual cases. Given the imperfection of human reason and our suspicion about the reasoning ability of the fact-finder, allowing decisions to be taken individually on the reliability and admissibility of hearsay evidence might over time produce a larger proportion of misjudgements than on the rule-based approach (Schauer 2006: 180–185; Schauer 2008). However, this argument is based on a large assumption about the likely effects of having exclusionary rules and not having them, and there is no strong empirical basis for thinking that the consequences are or will be as alleged (Goldman 1999: 292–295; Laudan 2006: 121–122).

Other supporters of exclusionary rules build their arguments on a wide range of different considerations. The literature is too vast to enter into details. Here is a brief mention of some arguments. On one theory, some exclusionary rules are devices that serve as incentives for lawyers to produce the epistemically best evidence that is reasonably available (Nance 1988, 2016: 195–201). For example, if lawyers are not allowed to rely on second-hand (hearsay) evidence, they will be forced to seek out better (first-hand) evidence. On another theory, exclusionary rules allocate the risks of error. Again, consider hearsay. The problem with allowing a party to rely on hearsay evidence is that the opponent has no opportunity to cross-examine the original maker of the statement and is thus deprived of an important means of attacking the reliability of the evidence. Exclusionary rules in general insulate the party against whom the evidence is sought to be adduced from the risks of error that the evidence, if admitted, would have introduced. The distribution of such risks is said to be a political decision that should not be left to the discretion of individual fact-finders (Stein 2005; cf. Redmayne 2006 and Nance 2007a: 154–164). It has also been argued that the hearsay rule and the accompanying right to confront witnesses promote the public acceptance and stability of legal verdicts. If the court relies on direct evidence, it can claim superior access to the facts (having heard from the horse’s mouth, so to speak) and this also reduces the risk of new information emerging after the trial to discredit the inference that was drawn from the hearsay evidence (the original maker of the statement might turn up after the trial to deny the truth of the statement that was attributed to him) (Nesson 1985: 1372–1375; cf. Park 1986; Goldman 1999: 282; Goldman 2005: 166–167).

3. Strength of Evidence

The decision whether to allow a party to adduce a particular item of evidence is one that the judge has to make and arises in the course of a trial. Section 2 above dealt with the conditions that must be satisfied for a witness’s testimony, a document or an object to be received as evidence. At the end of the trial, the fact-finder must consider all the evidence that has been presented and reach a verdict. Although verdict deliberation is sometimes subjected to various forms of control through legal devices such as presumptions and corroboration rules, such control is limited and the fact-finder is expected to exercise personal judgment in the evaluation of evidence (Damaška 2019). Having heard or seen the evidence, the fact-finder now has to evaluate or ‘weigh’ it in reaching the verdict. Weight can refer to any of the following three properties of evidence: (a) the probative value of individual items of evidence, (b) the sufficiency of the whole body of evidence adduced at the trial in meeting the standard of proof, or (c) the relative completeness of this body of evidence. The first two aspects of weight are familiar to legal practitioners but the third has been confined to academic discussions. These three ideas are discussed in the same order below.

In reaching the verdict, the trier of fact has to assess the probative value of the individual items of evidence which have been received at the trial. The concept of probative value can also play a role at the prior stage (which was the focus in section 2 ) where the judge has to make a ruling on whether to receive the evidence in the first place. In many legal systems, if the judge finds the probative value of a proposed item of evidence to be low and substantially outweighed by countervailing considerations, such as the risk of causing unfair prejudice or confusion, the judge can refuse to let the jury hear or see the evidence (see, e.g., Rule 403 of the United States’ Federal Rules of Evidence).

The concept of probative value (or, as it is also called, probative force) is related to the concept of relevance. Section 2.1.2 above introduced and examined the claim that the likelihood ratio is the measure of relevance. To recapitulate, the likelihood of an item of evidence, E (in our previous example, the likelihood of a blood type match) given a hypothesis H (that the accused is in fact guilty) is compared with the likelihood of E given the negation of H (that the accused is in fact innocent). Prior to the introduction of E , one may have formed some belief about H based on other evidence that one already has. This prior belief does not affect the likelihood ratio since its computation is based on the alternative assumptions that H is true and that H is false (Kaye 1986a; Kaye and Koehler 2003; cf. Davis and Follette 2002 and 2003). Rulings on relevance are made by the judge when objections of irrelevance are raised in the course of the trial. The relevance of an item of evidence is supposedly assessed on its own, without consideration of other evidence, and, indeed, much of the other evidence may have yet to presented at the point when the judge rules on the relevance of a particular item of evidence (Mnookin 2013: 1544–5). [ 12 ]

Probative value, as with relevance, has been explained in terms of the likelihood ratio (for detailed examples, see Nance and Morris 2002; Finkelstein and Levin 2003). It was noted earlier that evidence is either relevant or not, and, on the prevailing understanding, it is relevant so long as the likelihood ratio deviates from 1:1. But evidence can be more or less probative depending on the value of the likelihood ratio. In our earlier example, the probative value of a blood type match was 1.0:0.5 (or 2:1) as 50% of the suspect population had the same blood type as the accused. But suppose the blood type is less common and only 25% of the suspect population has it. The probative value of the evidence is now 1.0:0.25 (or 4:1). In both cases, the evidence is relevant; but the probative value is greater in the latter than in the former scenario. It is tempting to describe probative value as the degree of relevance but this would be misleading as relevance in law is a binary concept.

There is a second way of thinking about probative value. On the second view, but not on the first, the probative value of an item of evidence is assessed contextually. The probative value of E may be low given one state of the other evidence and substantial given a different body of other evidence (Friedman 1986; Friedman and Park 2003; cf. Davis and Follette 2002, 2003). Where the other evidence shows that a woman had died from falling down an escalator at a mall while she was out shopping, her husband’s history of spousal battery is unlikely to have any probative value in proving that he was responsible for her death. But where the other evidence shows that the wife had died of injuries in the matrimonial home, and the question is whether the injuries were sustained from an accidental fall from the stairs or inflicted by the husband, the same evidence of spousal battery will now have significant probative value.

On the second view, the probative value of an item of evidence ( E ) is not measured simply by the likelihood ratio as it is on the first view. Probative value is understood as the degree to which E increases (or decreases) the probability of the proposition or hypothesis ( H ) in support of (or against) which E is led. The probative value of E is measured by the difference between the probability of H given E (the posterior probability) and the probability of H absent E (the prior probability) (Friedman 1986; James 1941: 699).

Probative value of \(E = P(H | E) - P(H)\)

\(P(H | E)\) (the posterior probability) is derived by applying Bayes’ theorem—that is, by multiplying the prior probability by the likelihood ratio (see discussion in section 3.2.2 below). On the present view, while the likelihood ratio does not itself measure the probative value of E , it is nevertheless a crucial component in the assessment.

A major difficulty with both of the mathematical conceptions of probative value that we have just examined is that for most evidence, obtaining the figures necessary for computing the likelihood ratio is problematic (Allen 1991: 380). Exceptionally, quantitative base rates data exist, as in our blood type example. Where objective data is unavailable, the fact-finder has to draw on background experience and knowledge to come up with subjective values. In our blood type example, a critical factor in computing the likelihood ratio was the percentage of the “suspect population” who had the same blood type as the accused. “Reference class” is the general statistical term for the role that the suspect population plays in this analysis. How should the reference class of “suspect population” be defined? Should we look at the population of the country as a whole or of the town or the street where the alleged murder occurred? What if it occurred at an international airport where most the people around are foreign visitors? Or what if it is shown that both the accused and the victim were at the time of the alleged murder inmates of the same prison? Should we then take the prison population as the reference class? The distribution of blood types may differ according to which reference class is selected. Sceptics of mathematical modelling of probative value emphasize that data from different reference classes will have different explanatory power and the choice of the reference class is open to—and should be subjected to—contextual argument and requires the exercise of judgment; there is no a priori way of determining the correct reference class. (On the reference class problem in legal factfinding, see, in addition to references cited in the rest of this section, Colyvan, Regan, and Ferson 2001; Tillers 2005; Allen and Roberts 2007.)

Some writers have proposed quantifiable ways of selecting, or assisting in the selection, of the appropriate reference class. On one suggestion, the court does not have to search for the optimal reference class. A general characteristic of an adversarial system of trial is that the judge plays a passive role; it is up to the parties to come up with the arguments on which they want to rely and to produce evidence in support of their respective arguments. This adversarial setting makes the reference class problem more manageable as the court need only to decide which of the reference classes relied upon by the parties is to be preferred. And this can be done by applying one of a variety of technical criteria that statisticians have developed for comparing and selecting statistical models (Cheng 2009). Another suggestion is to use the statistical method of “feature selection” instead. The ideal reference class is defined by the intersection of all relevant features of the case, and a feature is relevant if it is correlated to the matter under enquiry (Franklin 2010, 2011: 559–561). For instance, if the amount of drug likely to be smuggled is reasonably believed to co-vary with the airport through which it is smuggled, the country of origin and the time period, and there is no evidence that any other feature is relevant on which data is available, the ideal reference class is the class of drug smugglers passing through that airport originating from that country and during that time period. Both suggestions have self-acknowledged limitations: not least, they depend on the availability of suitable data. Also, as Franklin stresses, while statistical methods “have advice to offer on how courts should judge quantitative evidence”, they do so “in a way that supplements normal intuitive legal argument rather than replacing it by a formula” (Franklin 2010: 22).

The reference class problem is not confined to the probabilistic assessment of the probative value of individual items of evidence. It is a general difficulty with a mathematical approach to legal proof. In particular, the same problem arises on a probabilistic interpretation of the standard of proof when the court has to determine whether the standard is met based on all the evidence adduced in the case. This topic is explored in section 3.2 below but it is convenient at this juncture to illustrate how the reference class problem can also arise in this connection. Let it be that the plaintiff sues Blue Bus Company to recover compensation for injuries sustained in an accident. The plaintiff testifies, and the court believes on the basis of his testimony, that he was run down by a recklessly driven bus. Unfortunately, it was dark at the time and he cannot tell whether the bus belonged to Blue Bus Company. Assume further that there is also evidence which establishes that Blue Bus Company owns 75% of the buses in the town where the accident occurred and the remaining 25% is owned by Red Bus Company. No other evidence is presented. To use the data as the basis for inferring that there is 0.75 probability that the bus involved in the accident was owned by Blue Bus Company would seem to privilege the reference class of “buses operating in the town” over other possible reference classes such as “buses plying the street where the accident occurred” or “buses operating at the time in question” (Allen and Pardo 2007a: 109). Different reference classes may produce very different likelihood ratios. It is crucial how the reference class is chosen and this is ultimately a matter of argument and judgment. Any choice of reference class (other than the class that shares every feature of the particular incident, which is, in effect, the unique incident itself) is in principle contestable.

Critics of the mathematization of legal proof raise this point as an example of inherent limitations to the mathematical modelling of probative value (Allen and Pardo 2007a). [ 13 ] Allen and Pardo propose an alternative, the explanatory theory of legal proof. They claim that this theory has the advantage of avoiding the reference class problem because it does not attempt to quantify probative value (Pardo 2005: 374–383; Pardo and Allen 2008: 261, 263; Pardo 2013: 600–601). Suppose a man is accused of killing his wife. Evidence is produced of his extra-marital affair. The unique probative value of the accused’s infidelity cannot be mathematically computed from statistical base rates of infidelity and uxoricides (husbands murdering wives). In assessing its probative value, the court should look instead at how strongly the evidence of infidelity supports the explanation of the material events put forward by the side adducing the evidence and how strongly it challenges the explanation offered by the opponent. For instance, the prosecution may be producing the evidence to buttress its case that the accused wanted to get rid of his wife so that he could marry his mistress, and the defence may be advancing the alternative theory that the couple was unusual in that they condoned extra-marital affairs and had never let it affect their loving relationship. How much probative value the evidence of infidelity has depends on the strength of the explanatory connections between it and the competing hypotheses, and this is not something that can be quantified.

But the disagreement in this debate is not as wide as it might appear. The critics concede that formal models for evaluating evidence in law may be useful. What they object to is

scholarship arguing … that such models establish the correct or accurate probative value of evidence, and thus implying that any deviations from such models lead to inaccurate or irrational outcomes. (Allen and Pardo 2007b: 308)

On the other side, it is acknowledged that there are limits to mathematical formalisation of evidential reasoning in law (Franklin 2012: 238–9) and that context, argument and judgment do play a role in identifying the reference class (Nance 2007b).

3.2 Sufficiency of Evidence and the Standards of Proof

In the section 3.1 above, we concentrated on the weight of evidence in the sense of probative value of individual items of evidence. The concept of weight can also apply to the total body of evidence presented at the trial; here “weight” is commonly referred to as the “sufficiency of evidence”. [ 14 ] The law assigns the legal burden of proof between parties to a dispute. For instance, at a criminal trial, the accused is presumed innocent and the burden is on the prosecution to prove that he is guilty as charged. To secure a conviction, the body of evidence presented at the trial must be sufficient to meet the standard of proof. Putting this generally, a verdict will be given in favour of the side bearing the legal burden of proof only if, having considered all of the evidence, the fact-finder is satisfied that the applicable standard of proof is met. The standard of proof has been given different interpretations.

On one interpretation, the standard of proof is a probabilistic threshold. In civil cases, the standard is the “balance of probabilities” or, as it is more popularly called in the United States, the “preponderance of evidence”. The plaintiff will satisfy this standard and succeed in his claim only if there is, on all the evidence adduced in the case, more than 0.5 probability of his claim being true. At criminal trials, the standard for a guilty verdict is “proof beyond a reasonable doubt”. Here the probabilistic threshold is thought to be much higher than 0.5 but courts have eschewed any attempt at authoritative quantification. Typically, a notional value, such as 0.9 or 0.95, is assumed by writers for the sake of discussion. For the prosecution to secure a guilty verdict, the evidence adduced at the trial must establish the criminal charge to a degree of probability that crosses this threshold. Where, as in the United States, there is an intermediate standard of “clear and convincing evidence” which is reserved for special cases, the probabilistic threshold is said to lie somewhere between 0.5 and the threshold for proof beyond reasonable doubt.

Kaplan was among the first to employ decision theory to develop a framework for setting the probabilistic threshold that represents the standard of proof. Since the attention in this area of the law tends to be on the avoidance of errors and their undesirable consequences, he finds it convenient to focus on disutility rather than utility. The expected disutility of an outcome is the product of the disutility (broadly, the social costs) of that outcome and the probability of that outcome. Only two options are generally available to the court: in criminal cases, it must either convict or acquit the accused and in civil cases, it has to give judgment either for the plaintiff or for the defendant. At a criminal trial, the decision should be made to convict where the expected disutility of a decision to acquit is greater than the expected disutility of a decision to convict. This is so as to minimize the expected disutilities. To put this in the form of an equation:

P is the probability that the accused is guilty on the basis of all the evidence adduced in the case, Dag is the disutility of acquitting a guilty person and Dci is the disutility of convicting an innocent person. A similar analysis applies to civil cases: the defendant should be found liable where the expected disutility of finding him not liable when he is in fact liable exceeds the expected disutility of finding him liable when he is in fact not liable.

On this approach, a person should be convicted of a crime only where P is greater than:

The same formula applies in civil cases except that the two disutilities ( Dag and Dci ) will have to be replaced by their civil equivalents (framed in terms of the disutility of awarding the judgment to a plaintiff who in fact does not deserve it and disutility of awarding the judgment to a defendant who in fact does not deserve it). On this formula, the crucial determinant of the standard of proof is the ratio of the two disutilities. In the civil context, the disutility of an error in one direction is deemed equal to the disutility of an error in the other direction. Hence, a probability of liability of greater than 0.5 would suffice for a decision to enter judgment against the defendant (see Redmayne 1996: 171). The situation is different at a criminal trial. Dci , the disutility of convicting an innocent person is considered far greater than Dag , the disutility of acquitting a guilty person. [ 15 ] Hence, the probability threshold for a conviction should be much higher than 0.5 (Kaplan 1968: 1071–1073; see also Cullison 1969).

An objection to this analysis is that it is incomplete. It is not enough to compare the costs of erroneous verdicts. The utility of an accurate conviction and the utility of an accurate acquittal should also be considered and factored into the equation (Lillquist 2002: 108). [ 16 ] This results in the following modification of the formula for setting the standard of proof:

Ucg is the utility of convicting the guilty, Uag is the utility of acquitting the guilty, Uai is the utility of acquitting the innocent and Uci the utility of convicting the innocent.

Since the relevant utilities depend on the individual circumstances, such as the seriousness of the crime and the severity of the punishment, the decision-theoretic account of the standard of proof would seem, on both the simple and the modified version, to lead to the conclusion that the probabilistic threshold should vary from case to case (Lillquist 2002; Bartels 1981; Laudan and Saunders 2009; Ribeiro 2019). In other words, the standard of proof should be a flexible or floating one. This view is perceived to be problematic.

First, it falls short descriptively. The law requires the court to apply a fixed standard of proof for all cases within the relevant category. In theory, all criminal cases are governed by the same high standard and all civil cases are governed by the same lower standard. That said, it is unclear whether factfinders in reality adhere strictly to a fixed standard of proof (see Kaplow 2012: 805–809).

The argument is better interpreted as a normative argument—as advancing the claim about what the law ought to be and not what it is. The standard of proof ought to vary from case to case. But this proposal faces a second objection. For convenience, the objection will be elaborated in the criminal setting; in principle, civil litigants have the same two rights that we shall identify. According to Dworkin (1981), moral harm arises as an objective moral fact when a person is erroneously convicted of a crime. Moral harm is distinguished from the bare harm (in the form of pain, frustration, deprivation of liberty and so forth) that is suffered by a wrongfully convicted and punished person. While accused persons have the right not to be convicted if innocent, they do not have the right to the most accurate procedure possible for ascertaining their guilt or innocence. However, they do have the right that a certain weight or importance be attached to the risk of moral harm in the design of procedural and evidential rules that affect the level of accuracy. Accused persons have the further right to a consistent weighting of the importance of moral harm and this further right stems from their right to equal concern and respect. Dworkin’s theory carries an implication bearing on the present debate. It is arguable that to adopt a floating standard of proof would offend the second right insofar as it means treating accused persons differently with respect to the evaluation of the importance of avoiding moral harm. This difference in treatment is reflected in the different level of the risk of moral harm to which they are exposed.

There is a third objection to a floating standard of proof. Picinali (2013) sees fact-finding as a theoretical exercise that engages the question of what to believe about the disputed facts. What counts as “reasonable” for the purposes of applying the standard of proof beyond reasonable doubt is accordingly a matter for theoretical as opposed to practical reasoning. Briefly, theoretical reasoning is concerned with what to believe whereas practical reasoning is about what to do. Only reasons for belief are germane in theoretical reasoning. While considerations that bear on the assessment of utility and disutility provide reasons for action, they are not reasons for believing in the accused’s guilt. Decision theory cannot therefore be used to support a variable application of the standard of proof beyond reasonable doubt.

The third criticism of a flexible standard of proof does not directly challenge the decision-theoretic analysis of the standard of proof. On that analysis, it would seem that the maximisation of expected utility is the criterion for selecting the appropriate probabilistic threshold to apply and it plays no further role in deciding whether that threshold, once selected, is met on the evidence adduced in the particular case. It is not incompatible with the decision-theoretic analysis to insist that the question of whether the selected threshold is met should be governed wholly by epistemic considerations. However, it is arguable that what counts as good or strong enough theoretical reason for judging, and hence believing, that something is true is dependent on the context, such as what is at stake in believing that it is true. More is at stake at a trial involving the death penalty than in a case of petty shop-lifting; accordingly, there should be stronger epistemic justification for a finding of guilt in the first than in the second case. Philosophical literature on epistemic contextualism and on interest-relative accounts of knowledge and justified belief has been drawn upon to support a variant standard of proof (Ho 2008: ch. 4; see also Amaya 2015: 525–531). [ 17 ]

The premise of the third criticism is that the trier of fact has to make a finding on a disputed factual proposition based on his belief in the proposition. This is contentious. Beliefs are involuntary; we cannot believe something by simply deciding to believe it. The dominant view is that beliefs are context-independent; at any given moment, we cannot believe something in one context and not believe it in another. On the other hand, legal fact-finding involves choice and decision making and it is dependent on the context; for example, evidence that is strong enough to justify a finding of fact in a civil case may not be strong enough to justify the same finding in a criminal case where the standard of proof is higher. It has been argued that the fact-finder has to base his findings not on what he believes but what he accepts (Cohen 1991, 1992: 117–125, Beltrán 2006; cf. Picinali 2013: 868–869). Belief and acceptance are propositional attitudes: they are different attitudes that one can have in relation to a proposition. As Cohen (1992: 4) explains:

to accept that p is to have or adopt a policy of deeming, positing or postulating that p —i.e. of including that proposition or rule among one’s premises for deciding what to do or think in a particular context.

Understanding standards of proof in terms of mathematical probabilities is controversial. It is said to raise a number of paradoxes (Cohen 1977; Allen 1986, 1991; Allen and Leiter 2001; Redmayne 2008). Let us return to our previous example. The defendant, Blue Bus Company, owns 75% of the buses in the town where the plaintiff was injured by a recklessly driven bus and the remaining 25% is owned by Red Bus Company. No other evidence is presented. Leaving aside the reference class problem discussed above, there is a 0.75 probability that the accident was caused by a bus owned by the defendant. On the probabilistic interpretation of the applicable standard of proof (that is, the balance of probabilities), the evidence should be sufficient to justify a verdict in the plaintiff’s favour. But most lawyers would agree that the evidence is insufficient. Another familiar hypothetical scenario is set in the criminal context (Nesson 1979: 1192–1193). Twenty five prisoners are exercising in a prison yard. Twenty four of them suddenly set upon a guard and kill him. The remaining prisoner refuses to participate. We cannot in the ensuing confusion identify the prisoner who refrained from the attack. Subsequently, one prisoner is selected randomly and prosecuted for the murder of the guard. Those are the only facts presented at the trial. The applicable standard is proof beyond a reasonable doubt. Assume that the probabilistic threshold of this standard is 0.95. On the statistical evidence, there is a probability of 0.96 that the defendant is criminally liable. [ 18 ] Despite the statistical probability of liability exceeding the threshold, it is widely agreed that the defendant must be acquitted. In both of the examples just described, why is the evidence insufficient and what does this say about legal standards of proof?

Various attempts have been made to find the answers (for surveys of these attempts, see Enoch and Fisher 2015: 565–571; Redmayne 2008, Ho 2008: 135–143, 168–170; Gardiner 2019b; section 6 of the entry on legal probabilism ). It has been argued that meeting a legal standard of proof is not merely or fundamentally a matter of adducing evidence to establish a mathematical probability of liability beyond a certain level. Standards of proof should be interpreted in epistemic rather than probabilistic terms. According to one interpretation, the evidence is sufficient to satisfy a standard of proof only if it is capable of justifying full or outright belief in the material facts that constitute legal liability and bare statistical evidence, as in our examples, cannot justify such a belief. (Nelkin 2021; Smith 2018; Buchak 2014; Ho 2008: 89–99.) On Smith’s account, the statistical evidence in our two examples fails to justify belief in the proposition that the defendant is liable because the evidence does not normically support that proposition. Evidence normically supports a proposition just in case the situation in which the evidence is true and the proposition is false is less normal, in the sense of requiring more explanation, than the situation in which the evidence and the proposition are both true. Where all that we have is statistical evidence, it could just so happen that the material proposition is false (it could just so happen that the accident-causing bus was red or that the accused was the one who refused to join in the murder), so no further explanation is needed where the proposition is false than where it is true (Smith 2018).

On a different epistemic interpretation, the evidence is sufficient to meet a legal standard of proof, and a finding of legal liability is permissible, only if the factfinder can gain knowledge of the defendant’s liability—to be precise, of the material facts establishing such liability—from the evidence (Duff et al. 2007: 87–91; Pardo 2010; for a critical overview of knowledge-centered accounts, see Gardiner forthcoming). High probability of liability alone will not suffice. On more subtle knowledge-centered theories, the standards of proof are met only if, on the available evidence, there is a sufficiently high probability that the fact finder knows that the defendant is liable (Littlejohn 2020 and 2021; Blome-Tillmann 2017), or only if the fact finder’s credence in the defendant’s liability exceeds the relevant legal threshold and the credence constitutes knowledge (Moss 2018). It is further claimed that the relevant knowledge necessary for a finding of liability cannot be obtained from statistical evidence alone (Littlejohn 2020 and 2021; Blome-Tillmann 2017; Moss 2018 and forthcoming). According to Thomson, this is because the statistical evidence (to take our first example, the 75% ownership of blue buses) is not causally connected with the fact sought to be proved and cannot guarantee the truth of the relevant belief (that the bus which caused the accident was blue) (Thomson 1986). An alternative argument is that knowledge requires the ruling out of all relevant alternatives and, to take our prison scenario, there is no evidence that addresses the possibility that the defendant was the one who refrained from joining in the attack or the possibility that the defendant is less likely to be guilty than an arbitrary prisoner in the yard. (See Moss forthcoming; Moss 2018: 213. Gardiner 2019a adapts the relevant alternatives framework to model legal standards of proof in a non-mathematical way while eschewing a knowledge account of those standards.) Another possible explanation for the failure to know relies on the notion of sensitivity. The belief that the defendant is liable is not sensitive to the truth where it is based on bare statistical evidence; in the bus example, evidence of the market share of buses remain the same whether it is true or not that a blue bus caused the accident (cf. Enoch, Spectre, and Fisher 2012; Enoch and Fisher 2015; Enoch and Spectre 2019 – while suggesting that the lack of knowledge has generally to do with the insensitivity of the belief, the authors deny that knowledge should matter to the imposition of legal liability). Yet another explanation is that it is unsafe to find a person liable on bare statistical evidence. Though safety is sometimes treated as a condition of knowledge (in that knowledge requires a true belief that is safe), one can treat safety as a condition for finding the defendant liable without also taking the position that the finding must be based on knowledge of liability. Safety is commonly understood in terms of whether a belief formed on the same basis would be true in close possible worlds. Roughly, a finding of liability is unsafe where it can easily be wrong in the sense that little in the actual world needs to change for it to be wrong. Whether the requirement of safety can explain why judgment should not entered against the defendant in our two hypothetical cases would depend on whether it can easily happen that the accident-causing bus was red or that the accused is innocent. (See Pritchard 2015 and 2018; Pardo 2018; cf. Gardiner 2020.) While theorizing of standards of proof in epistemic terms has gathered pace in recent years, it is criticised for relying on unrealistic hypotheticals that fail to attend to the actual operation of legal systems and for making impossible epistemological demands (Allen 2020).

There is another paradox in the mathematical interpretation of the standard of proof. This is the “conjunction paradox”. To succeed in a civil claim (or a criminal prosecution), the plaintiff (or the prosecution) will have to prove the material facts—or “elements”—that constitute the civil claim (or criminal charge) that is before the court (see discussion of “materiality” in section 2.2 above). Imagine a claim under the law of negligence that rests on two elements: a breach of duty of care by the defendant (element A ) and causation of harm to the plaintiff (element B ). To win the case, the plaintiff is legally required to prove A and B . For the sake of simplicity, let A and B be mutually independent events. Suppose the evidence establishes A to a probability of 0.6 and B to a probability of 0.7. On the mathematical interpretation of the civil standard of proof, the plaintiff should succeed in his claim since the probability with respect to each of the elements exceeds 0.5. However, according to the multiplication rule of conventional probability calculus, the probability that A and B are both true is the product of their respective probabilities; in this example, it is only 0.42 (obtained by multiplying 0.6 with 0.7). Thus, the overall probability is greater that the defendant deserves to win than that the plaintiff deserves to win, and yet the verdict is awarded in favour of the plaintiff.

One way of avoiding the conjunction paradox is to take the position that it should not be enough for each element to cross the probabilistic threshold; the plaintiff (or the prosecution) should win only if the probability of the plaintiff’s (or prosecution’s) case as a whole exceeds the applicable probabilistic threshold. So, in our example, the plaintiff should lose since the overall probability is below 0.5. But this suggested solution is unsatisfactory. The required level of overall probability would then turn on how many elements the civil claim or criminal charge happens to have. The greater the number of elements, the higher the level of probability to which, on average, each of them must be proved. This is thought to be arbitrary and hence objectionable. As two commentators noted, the legal definition of theft contains more elements than that for murder. Criminal law is not the same in all countries. We may take the following as a convenient approximation of what the law is in some countries: murder is (1) an act that caused the death of a person (2) that was done with the intention of causing the death, and to constitute theft, there must be (1) an intention to take property, (2) dishonesty in taking the property, (3) removal of the property from the possession of another person, and (4) lack of consent by that person. Since the offence of theft contains twice the number of elements as compared to murder, the individual elements for theft would have to be proved to a much higher level of probability (in order for the probability of their conjunction to cross the overall threshold) than the individual elements for the much more serious crime of murder (Allen and Leiter 2001: 1504–5). This is intuitively unacceptable.

Another proposal for resolving the conjunction paradox is move away from thinking of the standard of proof as a quantified threshold of absolute probability and to construe it, instead, as a probability ratio. The fact-finder has to compare the probability of the evidence adduced at the trial under the plaintiff’s theory of the case with the probability of the evidence under the defendant’s theory of the case (the two need not add to 1), and award the verdict to the side with a higher probability (Cheng 2013). One criticism of this interpretation of the standard of proof is that it ignores, and does not provide a basis for ignoring, the margin by which one probability exceeds the other, and the difference in probability may vary significantly for different elements of the case (Allen and Stein 2013: 598).

There is a deeper problem with the probabilistic conception of the standard of proof. There does not seem to be a satisfactory interpretation of probability that suits the forensic context. The only plausible candidate is the subjective meaning of probability according to which probability is construed as the strength of belief. The evidence is sufficient to satisfy the legal standard of proof on a disputed question of fact—for example, it is sufficient to justify the positive finding of fact that the accused killed the victim—only if the fact-finder, having considered the evidence, forms a sufficiently strong belief that the accused killed the victim. Guidance on how to process evidence and form beliefs can be found in a mathematical theorem known as Bayes’ theorem; it is the method by which an ideal rational fact-finder would revise or update his beliefs in the light of new evidence. [ 19 ] To return to our earlier hypothetical scenario, suppose the fact-finder initially believes the odds of the accused being guilty is 1:1 (“prior odds”) or, putting this differently, that there is a 0.5 probability of guilt. The fact-finder then receives evidence that blood of type A was found at the scene of the crime and that the accused has type A blood. Fifty percent of the population has this blood type. On the Bayesian approach, the posterior odds are calculated by multiplying the prior odds (1:1) by the likelihood ratio (which, as we saw in section 2.1.2 above, is 2:1). The fact-finder’s belief in the odds of guilt should now be revised to 2:1; the probability of guilt is now increased to 0.67 (Lempert 1977).

The subjectivist Bayesian theory of legal fact-finding has come under attack (see generally Amaya 2015: 82–93; Pardo 2013: 591). First, as we already saw in section 3.1 , ascertainment of the likelihood ratios is highly problematic. Secondly, the Bayesian theory is not sensitive to the weight of evidence which, roughly put, is the amount of evidence that is available. This criticism and the concept of weight are further explored in section 3.3 .

Thirdly, while the Bayesian theorem offers a method for updating probabilities in the light of new evidence, it is silent on what the initial probability should be. In a trial setting, the initial probability cannot be set at zero since this means certainty in the innocence of the accused. No new evidence can then make any difference; whatever the likelihood ratio of the evidence, multiplying it by zero (the prior probability) will still end up with a posterior probability of zero. On the other hand, starting with an initial probability is also problematic. This is especially so in a criminal case. To start a trial with some probability of guilt is to have the fact-finder harbouring some initial belief that the accused is guilty and this is not easy to reconcile with the presumption of innocence. (Tribe 1971: 1368–1372; cf. Posner 1999: 1514, suggesting starting the trial with prior odds of 50:50, criticized by Friedman 2000. The problem of fixing the prior probability is said to disappear if we base fact-finding simply on likelihood ratios: Sullivan, 2019: 45–59.)

Fourthly, we have thus far relied for ease of illustration on highly simplified—and therefore unrealistic—examples. In real cases, there are normally multiple and dependent items of evidence and the probabilities of all possible conjunctions of these items, which are numerous, will have to be computed. These computations are far too complex to be undertaken by human beings (Callen 1982: 10–15). The impossibility of complying with the Bayesian model undermines its prescriptive value.

Fifthly, according to Haack, the Bayesian theory has it the wrong way round. What matters is not the strength of the fact-finder’s belief itself. The standard of proof should be understood instead in terms of what it is reasonable for the fact-finder to believe in the light of the evidence presented, and this is a matter of the degree to which the belief is warranted by the evidence. Evidence is legally sufficient where it warrants the contested factual claim to the degree required by law. Whether a factual claim is warranted by the evidence turns on how strongly the evidence supports the claim, on how independently secure the evidence is, and on how much of the relevant evidence is available to the fact-finder (that is, the comprehensiveness of the evidence—see further discussion in section 3.3 below). Haack is against identifying degrees of warrant with mathematical probabilities. Degrees of warrant do not conform to the axioms of the standard probability calculus. For instance, where the evidence is weak, neither p nor not- p may be warranted; in contrast, the probability of p and the probability of not- p must add up to 1. Further, where the probability of p and the probability of q are both less than 1, the probability of p and q , being the product of the probability of p and the probability of q , is less than the probability of either. On the other hand, the degree of warrant for the conjunction of p and q may be higher than the warrant for either. [ 20 ] (See Haack 2004, 2008a,b, 2012, 2014 for the legal application of her general theory of epistemology. For her general theory of epistemology, see Haack 1993: ch. 4; Haack 2009: ch. 4; Haack 2003: ch. 3.)

Sixthly, research in experimental psychology suggests that fact-finders do not evaluate pieces of evidence one-by-one and in the unidirectional manner required under the mathematical model (Amaya 2015: 114–5). A holistic approach is taken instead where the discrete items of evidence are integrated into large cognitive structures (variously labelled as “mental models”, “stories”, “narratives” and “theories of the case”), and they are assessed globally against the legal definition of the crime or civil claim that is in dispute (Pennington and Hastie 1991, 1993; Pardo 2000). The reasoning does not progress linearly from evidence to a conclusion; it is bi-directional, going forward and backward: as the fact-finder’s consideration of the evidence inclines him towards a particular verdict, his leaning towards that conclusion will often produce a revision of his original perception and his assessment of the evidence (Simon 2004, 2011).

The holistic nature of evidential reasoning as revealed by these studies has inspired alternative theories that are of a non-mathematical nature. One alternative, already mentioned, is the “explanatory” or “relative plausibility” theory advanced by Allen together with Pardo and other collaborators (Allen 1986, 1991, 1994; Pardo 2000; Allen and Leiter 2001; Allen and Jehl 2003; Pardo and Allen 2008; Allen and Pardo 2019; cf. Nance 2001, Friedman 2001). [ 21 ] They contend that fact-finders do not reason in the fashion portrayed by the Bayesian model. Instead, they engage in generating explanations or hypotheses on the available evidence by a process of abductive reasoning or drawing “inferences to the best explanation”, and these competing explanations or hypotheses are compared in the light of the evidence. [ 22 ] The comparison is not of a hypothesis with the negation of that hypothesis, where the probability of a hypothesis is compared with the probability of its negation. Instead, the comparison is of one hypothesis with one or more particular alternative hypotheses as advocated by a party or as constructed by the fact-finder himself. On this approach, the plausibility of X, the factual account of the case that establishes the accused’s guilt or defendant’s liability, is compared with the plausibility of a hypothesis Y, a specific alternative account that points to the accused’s innocence or the defendant’s non-liability, and there may be more than one such specific alternative account.

On this theory, the evidence is sufficient to satisfy the preponderance of proof standard when the best-available hypothesis that explains the evidence and the underlying events include all of the elements of the claim. Thus, in a negligence case, the best-available hypothesis would have to include a breach of duty of care by the plaintiff and causation of harm to the defendant as these are the elements that must be proved to succeed in the legal claim. For the intermediate “clear-and-convincing” standard of proof, the best-available explanation must be substantially better than the alternatives. To establish the standard of proof beyond reasonable doubt, there must be a plausible explanation of the evidence that includes all of the elements of the crime and, in addition, there must be no plausible explanation that is consistent with innocence (Pardo and Allen 2008: 238–240; Pardo 2013: 603–604).

The relative plausibility theory itself is perceived to have a number of shortcomings. [ 23 ] First, the theory portrays the assessment of plausibility as an exercise of judgment that involves employment of various criteria such as coherence, consistency, simplicity, consilience, and more. However, the theory is sketchy on the meaning of plausibility and the criteria for evaluating plausibility are left largely unanalyzed. [ 24 ]

A second criticism of the relative plausibility theory is that, despite the purported utilisation of “inference to the best explanation” reasoning, the verdict is not controlled by the best explanation. For instance, even if the prosecution’s hypothesis is better than the defence’s hypothesis, neither may be very good. In these circumstances, the court must reject the prosecution’s hypothesis even though it is the best of alternatives (Laudan 2007). One suggested mitigation of this criticism is to place some demand on the epistemic effort that the trier of fact must take (for example, by being sufficiently diligent and thorough) in constructing the set of hypotheses from which the best is to be chosen (Amaya 2009: 155).

The third criticism is targeted at holistic theories of evidential reasoning in general and not specifically at the relative plausibility theory. While it may be descriptively true that fact-finders decide verdicts by holistic evaluation of the plausibility of competing explanations, hypotheses, narratives or factual theories that are generated from the evidence, such forms of reasoning may conceal bias and prejudice that stand greater chances of exposure under a systematic approach such as Bayesian analysis (Twining 2006: 319; Simon 2004, 2011; Griffin 2013). A hypothesis constructed by the fact-finder may be shaped subconsciously by a prejudicial generalisation or background belief about the accused based on a certain feature, say, his race or sexual history. Individuating this feature and subjecting it to Bayesian scrutiny has the desirable effect of putting the generalisation or background belief under the spotlight and forcing the fact-finder to confront the problem of prejudice.

A third idea of evidential weight is prompted by this insight from Keynes (1921: 71):

As the relevant evidence at our disposal increases, the magnitude of the probability of the argument may either decrease or increase, according as the new knowledge strengthens the unfavourable or the favourable evidence; but something seems to have increased in either case,—we have a more substantial basis upon which to rest our conclusion. I express this by saying that an accession of new evidence increases the weight of an argument. New evidence will sometimes decrease the probability of an argument, but it will always increase its “weight”.

This idea of evidential weight has been applied by some legal scholars in assessing the sufficiency of evidence in satisfying legal standards of proof. [ 25 ] At its simplest, we may think of weight in the context of legal fact-finding as the amount of evidence before the court. Weight is distinguishable from probability. The weight of evidence may be high and the mathematical probability low, as in the situation where the prosecution adduces a great deal of evidence tending to incriminate the accused but the defence has an unshakeable alibi (Cohen 1986: 641). Conversely, the state of evidence adduced in a case might establish a sufficient degree of probability—high enough to cross the supposed threshold of proof on the mathematical conception of the standard of proof—and yet lack adequate weight. In the much-discussed gate-crasher’s paradox, the only available evidence shows that the defendant was one of a thousand spectators at a rodeo show and that only four hundred and ninety nine tickets were issued. The defendant is sued by the show organiser for gate-crashing. The mathematical probability that the defendant was a gate-crasher is 0.501 and this meets the probabilistic threshold for civil liability. But, according to the negation principle of mathematical probability, there is probability of 0.499 that the defendant did pay for his entrance. In these circumstances, it is intuitively unjust to find him liable (Cohen 1977: 75). A possible explanation for not finding him liable is that the evidence is too flimsy or of insufficient weight.

Proponents of the mathematical conception of the standard of proof have stood their ground even while acknowledging that weight has a role to play in the Bayesian analysis of probative value and the sufficiency of evidence. If a party does not produce relevant evidence that is in his possession, resulting in the court facing an evidential deficiency, it may draw an adverse inference against him when computing the posterior probability (Kaye 1986b: 667; Friedman 1997). One criticism of this approach is that, in the absence of information about the missing evidence, the drawing of the adverse inference is open to the objection of arbitrariness (Nance 2008: 274). A further objection is that the management of parties’ conduct relating to evidence preservation and presentation should be left to judges and not to the jury. What a judge may do to optimize evidential weight is to impose a burden of producing evidence on a party and to make the party suffer an adverse finding of fact if he fails to produce the evidence. This will serve as an incentive for the party to act in a manner that promotes the interest in evidential completeness (Nance 2008, 2010, 2016).

Cohen suggests that the standard of proof should be conceived entirely as a matter of evidential weight which, on his theory, is a matter of the number of tests or challenges to which a factual hypothesis is subjected to in court. He offers an account of legal fact-finding in terms of an account of inductive probability that was inspired by the work of writers such as Francis Bacon and J.S. Mill. Inductive probability operates differently from the classical calculus of probability. It is based on inductive support for the common-sense generalisation that licences the drawing of the relevant inference. Inductive support for a generalisation is graded according to the number of tests that it has passed, or, putting this in another way, by the degree of its resistance to falsification by relevant variables. The inductive probability of an argument is equal to the reliability grade of the inductive support for the generalisation which covers the argument.

Proof beyond reasonable doubt represents the maximum level of inductive probability. The prosecution may try to persuade the court to infer that the accused was guilty of burglary by producing evidence to establish that he was found in the vicinity of the victim’s house late at night with the stolen object on him. This inference is licensed by the generalisation that normally if a stranger is found immediately after a burglary in possession of the stolen object, he intentionally removed it himself. The defence may try to defeat the inference by showing that the generalization does not apply in the particular case, for example, by presenting evidence to show that the accused had found the object on the street. The prosecution’s hypothesis is now challenged or put to the test. As a counter-move, it may produce evidence to establish that the object could not have been lying in the street as alleged. If the generalisations on which the prosecution’s case rest survive challenges by the defence at every possible point, then guilt is proved beyond reasonable doubt. [ 26 ] The same reasoning structure applies in the civil context except that in a civil case, the plaintiff succeeds in proof on the preponderance of evidence so long as the conclusion to be proved by him is more inductively probable than its negation. (Cohen 1977, 1986; cf. Schum 1979.) [ 27 ]

Cohen’s theory seems to require that each test to which a hypothesis is put can be unequivocally and objectively resolved. But usually this is not the case. In our example, we may not be entirely convinced that the accused found or did not find the object on the street, and our evaluation would involve the exercise of judgment that is no less subjective as the sort of judgments required when applying the standard probabilistic conception of proof (Nance 2008: 275–6; Schum 1994: 261).

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• Statistics and the Law , page at the Royal Statistical Society.

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Scientific Hypothesis, Model, Theory, and Law

Understanding the Difference Between Basic Scientific Terms

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Words have precise meanings in science. For example, "theory," "law," and "hypothesis" don't all mean the same thing. Outside of science, you might say something is "just a theory," meaning it's a supposition that may or may not be true. In science, however, a theory is an explanation that generally is accepted to be true. Here's a closer look at these important, commonly misused terms.

A hypothesis is an educated guess, based on observation. It's a prediction of cause and effect. Usually, a hypothesis can be supported or refuted through experimentation or more observation. A hypothesis can be disproven but not proven to be true.

Example: If you see no difference in the cleaning ability of various laundry detergents, you might hypothesize that cleaning effectiveness is not affected by which detergent you use. This hypothesis can be disproven if you observe a stain is removed by one detergent and not another. On the other hand, you cannot prove the hypothesis. Even if you never see a difference in the cleanliness of your clothes after trying 1,000 detergents, there might be one more you haven't tried that could be different.

Scientists often construct models to help explain complex concepts. These can be physical models like a model volcano or atom  or conceptual models like predictive weather algorithms. A model doesn't contain all the details of the real deal, but it should include observations known to be valid.

Example: The  Bohr model shows electrons orbiting the atomic nucleus, much the same way as the way planets revolve around the sun. In reality, the movement of electrons is complicated but the model makes it clear that protons and neutrons form a nucleus and electrons tend to move around outside the nucleus.

A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. A theory is valid as long as there is no evidence to dispute it. Therefore, theories can be disproven. Basically, if evidence accumulates to support a hypothesis, then the hypothesis can become accepted as a good explanation of a phenomenon. One definition of a theory is to say that it's an accepted hypothesis.

Example: It is known that on June 30, 1908, in Tunguska, Siberia, there was an explosion equivalent to the detonation of about 15 million tons of TNT. Many hypotheses have been proposed for what caused the explosion. It was theorized that the explosion was caused by a natural extraterrestrial phenomenon , and was not caused by man. Is this theory a fact? No. The event is a recorded fact. Is this theory, generally accepted to be true, based on evidence to-date? Yes. Can this theory be shown to be false and be discarded? Yes.

A scientific law generalizes a body of observations. At the time it's made, no exceptions have been found to a law. Scientific laws explain things but they do not describe them. One way to tell a law and a theory apart is to ask if the description gives you the means to explain "why." The word "law" is used less and less in science, as many laws are only true under limited circumstances.

Example: Consider Newton's Law of Gravity . Newton could use this law to predict the behavior of a dropped object but he couldn't explain why it happened.

As you can see, there is no "proof" or absolute "truth" in science. The closest we get are facts, which are indisputable observations. Note, however, if you define proof as arriving at a logical conclusion, based on the evidence, then there is "proof" in science. Some work under the definition that to prove something implies it can never be wrong, which is different. If you're asked to define the terms hypothesis, theory, and law, keep in mind the definitions of proof and of these words can vary slightly depending on the scientific discipline. What's important is to realize they don't all mean the same thing and cannot be used interchangeably.

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Understanding Racial and Ethnic Disparities in Arrest: The Role of Individual, Home, School, and Community Characteristics

Lauren nichol gase.

1 Division of Chronic Disease and Injury Prevention, Los Angeles County Department of Public Health, 3530 Wilshire Blvd, 8th Floor, Los Angeles, CA 90010, USA

Beth A. Glenn

2 Department of Health Policy and Management, UCLA Kaiser Permanente Center for Health Equity, Fielding School of Public Health, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Box 956900, A2-125 CHS, Los Angeles, CA 90095-6900, USA

Louis M. Gomez

3 Education Department, Graduate School of Education and Information Studies, University of California, Los Angeles, Box 951521, 1002 MH, Los Angeles, CA 90095-1521, USA

Moira Inkelas

4 Department of Health Policy and Management, Fielding School of Public Health, University of California, Los Angeles, 10990 Wilshire Blvd., Ste 900, Los Angeles, CA 90095-6939, USA

Ninez A. Ponce

5 Department of Health Policy and Management, Center for Health Policy Research, Fielding School of Public Health, University of California, Los Angeles, 10960 Wilshire Blvd., Ste 1550, Los Angeles, CA 90095-1772, USA

Contact with the justice system can lead to a range of poor health and social outcomes. While persons of color are disproportionately represented in both the juvenile and criminal justice systems, reasons for these patters remain unclear. This study sought to examine the extent and sources of differences in arrests during adolescence and young adulthood among blacks, whites, and Hispanics in the USA. Multilevel cross-sectional logistic regression analyses were conducted using data from waves I and IV of the National Longitudinal Study of Adolescent to Adult Health ( n = 12,752 respondents). Results showed significantly higher likelihood of having ever been arrested among blacks, when compared to whites, even after controlling for a range of delinquent behaviors (odds ratio = 1.58, 95 % confidence interval = 1.27, 1.95). These black–white disparities were no longer present after accounting for racial composition of the neighborhood, supporting the growing body of research demonstrating the importance of contextual variables in driving disproportionate minority contact with the justice system.

Introduction

Contact with the juvenile or criminal justice system can lead to a range of negative health and social outcomes. Contact with the justice system can damage social networks and family functioning, decrease high school graduation and employment rates, increase risk for involvement in violence and violent victimization, and worsen mental health outcomes and long-term life opportunities ( Brame et al. 2012 ; Clear 2008 ; Gatti et al. 2009 ; Hjalmarsson 2007 ; Lambie and Randell 2013 ; Massoglia 2008 ; Pridemore 2014 ; Turney et al. 2012 ).

Persons of color are disproportionately represented in both the juvenile and criminal justice systems. Among youths, the evidence for racial differences is greatest at the earliest point of contact, particularly at the stages of arrest, referral to court, and placement in secure detention ( National Research Council 2013 ). In 2013, more than one million youths in the USA had contact with the juvenile justice system; black youths experienced more than twice the rate of arrest than white youths ( Puzzanchera and Hockenberry 2015 ). Despite decreases in the number of youths entering the justice system in the past 20 years, overall reductions have not narrowed the gap. Arrest rates among white youths, for example, have been decreasing at a faster pace than arrest rates for black youths ( Stevens and Morash 2015 ). Data among adults show similar patterns; those who are arrested, incarcerated, and put on probation or parole come largely from disadvantaged segments of the population, mainly minority men who are poorly educated, lack work preparation or experience, and/or battle substance abuse disorders ( National Research Council 2014 ).

Despite well-documented racial differences in contact with the justice system, reasons for these disparities remain unclear. Researchers have conceptualized racial disparities as potentially stemming from differences in individual behaviors (offending), policies and practices of the justice system, and/or environmental and social contexts ( Piquero 2008 ). Unfortunately, the vast majority of studies conducted to date have focused on a narrow set of potential predictors and have not been able to fully examine the individual- and system-level characteristics that impact racial/ethnic disparities in justice system contact. The present study sought to help address these gaps by conducting a multilevel, cross-sectional analysis using data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) to simultaneously consider a more robust range of individual, home, school, and community factors in driving racial and ethnic disparities in the first point of contact with the justice system: arrest. Given the wide range of short- and long-term detrimental effects associated with justice system contact and its role in influencing inequities ( Brame et al. 2012 ; Schnittker and John 2007 ), by better articulating the factors driving racial/ethnic disparities in arrests, we can begin to identify leverage points to help shift health, social, and economic trajectories.

Disproportionate rates of minority contact with the justice system may be driven by a variety of factors; much of the extant literature has sought to distinguish between warranted factors (e.g., higher levels of criminal involvement) and unwarranted factors (i.e., those not explained by legally relevant variables) ( Crutchfield et al. 2009 ; Spohn 2000 ). The “differential involvement” hypothesis posits that minorities are overrepresented in the juvenile and criminal justice systems because they commit more crimes, for more extended periods of their lives, and partake in more of the types of crimes that lead to processing in the justice system, such as violence ( Piquero 2008 ). A number of studies using official police records and self-reported data support the notion of differential patterns of offending, particularly for violent behaviors ( Piquero 2008 ). Previous work by Felson and Deane (2007) , for example, identified higher rates of violence among black adolescents, particularly armed violence, even after controlling for demographic factors such as family structure, residence, and socioeconomic status. While early studies strongly supported the central role of differential offending, more recent work calls into question reliance on this hypothesis alone ( Piquero 2008 ; Piquero and Brame 2008 ). Longitudinal studies using data from Denver, Rochester, and Seattle showed that racial differences in police contact remain substantial after controlling for differences in self-reported offending ( Huizinga et al. 2007 ). Likewise, minority youths have been shown to be more likely to be involved with the justice system after controlling for criminal behaviors, substance abuse, and mental health problems ( Godette et al. 2011 ).

A contrasting explanation for disproportionate minority contact is the “differential selection and processing” hypothesis, the notion that juvenile and criminal justice system protocols and processes lead to more minorities being arrested, convicted, and incarcerated ( Piquero 2008 ). A meta-analysis of data collected at the encounter or suspect level reported that blacks had an increased likelihood of being arrested as compared to whites even after controlling for factors such as demeanor, offense severity, quantity of evidence at the scene, prior record of the suspect, and requests to arrest by victims ( Kochel et al. 2011 ). Experimental studies point to the role of unconscious racial stereotyping among law enforcement officials, for example, Graham and Lowery (2004) demonstrated the impact of racial priming on police and probation officer reports of negative traits, culpability, expected recidivism, and in endorsing harsher rates of punishment. Additionally, scholars have pointed to components of the system—including lack of adequate resources for legal counsel, pre-trial services, and drug treatment, which disproportionately impact racial/ethnic minority offenders—as contributing to the recycling of individuals within the system and further exacerbating disparities ( Taxman et al. 2005 ).

A more nuanced picture of the differential involvement/differential selection and processing framework warrants an expanded focus on environmental context. Neighborhoods in the USA are highly segregated; racial/ethnic minorities frequently face worse environmental, educational, and economic conditions ( Jargowsky 2015 ; Williams and Collins 2001 ). Differences in these environments can influence contact with the juvenile and criminal justice systems both indirectly (e.g., by influencing behavior) and directly (e.g., through increased crime rates and associated police presence). With regard to behavior, social disorganization theory suggests that conditions of socioeconomic disadvantage and residential instability disrupt social bonds and limit collective activity to maintain social control, thereby increasing the likelihood of deviant behaviors such as violence and child maltreatment ( Beyer et al. 2013 ; Cullen and Agnew 2011 ; Maguire-Jack and Klein 2015 ; Sampson and Groves 1989 ). Studies point to the role of residential segregation in influencing structural (concentrated) disadvantage and social isolation, which lead to structural barriers and cultural adaptations that undermine social organization, thereby increasing rates of neighborhood violence ( Krivo et al. 2009 ; Sampson 2013 ). Additionally, neighborhood racial/ethnic composition may result in greater exposure to crime-control measures (i.e., more law enforcement officials). Whether such differential crime-control efforts stem from a “consensus” (i.e., race-neutral, problem-oriented techniques which signal society's uniform desire for law enforcement to control disorder) or “conflict” (a deliberate attempt by the dominant social group to maintain social control and order) perspective is unclear ( Renauer 2012 ; Taxman et al. 2005 ). While conflict theories have been used to explain macro-level law enforcement behaviors, such as police force size and incarceration rates ( Davis and Sorensen 2013 ; Renauer 2012 ), findings supporting their influence on micro-level law enforcement practices have been mixed ( Arvanites 2014 ; Davis and Sorensen 2013 ; Parker et al. 2005 : Petrocelli et al. 2003 ).

Overall, much remains unknown about the relative contribution of individual, community, and system characteristics in influencing rates of disproportionate minority contact; a few multilevel studies help illustrate the complex array of factors that impact differential arrest rates among youths. Kirk's (2008) study of Chicago youths points to the importance of unstable family structure, concentrated poverty, and low levels of collective efficacy in influencing disparate arrest rates between whites and blacks. However, even after controlling for delinquent behaviors as well as other individual, family, and neighborhood-level factors, substantial differences in arrest remained between black youths and those in other racial groups. Work by Crutchfield and colleagues examining differences in rates of police contact (2012) and arrest (2009) among youths in Seattle illustrated the role of income, parental histories of arrest, delinquent peers, deviant adult networks, and school disciplinary practices in predicting disparities, after controlling for delinquent behaviors. Of interest was the importance of parental and other family criminal involvement which, as the authors concluded, may point to the role of law enforcement paying more attention to families known to be involved in crime. In one of the only studies of a nationally representative sample of youths, Anderson (2015) demonstrated disproportionate rates of arrest between black and white youths, but not between Hispanic and white youths, after controlling for self-reported delinquency. The study found these disparities to be magnified in predominantly non-black communities; however, it was only able to consider a limited number of community-level and no school-level factors in its analysis. Overall, there are likely to be a number of important contextual and individual factors that contribute to differential rates of contact with the justice system, many of which remain unexplored.

The present study sought to address some of the gaps in the current literature by examining a more comprehensive range of community, school, home (family), and individual characteristics to understand reasons underlying racial/ethnic disparities in arrest. To explore these issues, this study used the National Longitudinal Study of Adolescent to Adult Health (Add Health), which contains measures of a variety of factors, including adolescent self-reported delinquent behaviors, parental perceptions of home environments, and data on school and community characteristics. By using a nationally representative longitudinal dataset, this study sought to examine the extent and sources of disparities in arrests during adolescence and young adulthood among blacks, whites, and Hispanics in the USA. Specific research questions included: (1) To what extent are there racial/ethnic differences in arrest, and if present, to what extent are they explained by differences in individual-level delinquent behaviors? and (2) what aspects of community and school environments are associated with differences in arrests, after controlling for individual-level delinquent behavior and other individual and family-level characteristics?

Add Health is a large longitudinal dataset based on a nationally representative cohort of US adolescents. Youths were in grades 7–12 during the first year of administration (conducted from September 1994 through December 1995) (wave I). The cohort has been followed into young adulthood with four in-home interviews, the most recent of which was conducted from January 2008 through February 2009, when the sample was aged 24–32 years old (wave IV).

The data were collected using a school-based, clustered sampling design. A sample of 80 high schools and 52 middle schools from the USA was selected with unequal probability of selection. A school was eligible for the sample if it included an 11th grade and had a minimum enrollment of 30 students. Multiple types of youths were oversampled, including disabled, blacks from well-educated families, Chinese, Cubans, Puerto Ricans, and twins and siblings. As described by the survey creators, incorporating systematic sampling methods and implicit stratification into the study design helps ensure that the sample is representative of US schools with respect to region, urbanicity, school size, school type, and ethnicity ( Harris et al. 2009 ).

For this study, a subset of the data was extracted by merging variables from five Add Health files: the wave I adolescent in-home file, the wave I parental in-home questionnaire, the wave I school administrator questionnaire, the wave I contextual file, and the wave IV in-home questionnaire. Data from only waves I and IV were used to obtain information from the earliest formative years (wave I) and the most complete data on life experience (wave IV). Respondent data were collected in the youth's home during an in-person interview using standardized interview protocols. The majority of questions were asked directly by the interviewer; however, sensitive questions were administered using computer-assisted self-interview. For parental data, the mother (or other female head of the household) of the originally sampled adolescent was asked to participate in an interviewer-administered, paper-and-pencil survey. If the mother did not reside in the household, the following list was used to select the next most appropriate respondent: stepmother, other female guardian, father, stepfather, and other male guardian ( Harris et al. 2009 ). For school data, an administrator from each school was asked to complete a questionnaire. Finally, the contextual file data elements were developed based on either respondent addresses, GPS readings that allowed for geocoding, or (in a small proportion of cases) ZIP code data.

The outcome, whether an individual was ever arrested, was taken from the wave IV in-home question, “Have you ever been arrested?” To provide context related to the outcome, descriptive analyses were conducted using the following three questions related to arrests: How old a respondent was the first time he/she was arrested (open-ended question, dichotomized for analysis as whether or not the arrest occurred before age 18); how many times a respondent had been arrested (closed-ended question with response options of “once” or “more than once”); and what the respondent was charged with the first time he/she was arrested (closed-ended question with response options of “driving under the influence,” “other alcohol-related offenses,” “marijuana offenses,” “other drug offenses,” “robbery,” “theft,” “forcible rape,” “aggravated assault/intentional manslaughter/murder,” “simple assault,” “fraud, forgery, or embezzlement,” and “other offenses”).

Individual Characteristics

Demographics.

All demographic characteristics were taken from the wave I in-home questionnaire. Respondents were asked to identify their race. Response options included: white, black or African American, Asian or Pacific Islander, American Indian or Native American, or other. In a separate question, respondents were asked whether they were of Hispanic or Latino origin. All individuals who selected Hispanic were able to select one (or more) subgroup from the following: Mexican, Cuban, Puerto Rican, or Central/South American. From these questions, four mutually exclusive racial/ethnic categories were developed: non-Hispanic white, non-Hispanic black, Hispanic, and other. If participants selected more than one race, their self-identified category that “best describes their racial background” was used. Due to the small number of those who identified as Asian or Pacific Islander or American Indian or Native American, these responses were grouped with “other.” Based on the small number of respondents in each of the Hispanic subgroup categories, and results of preliminary analyses, which suggested no differences between Mexicans, Cubans, Puerto Ricans, or Central/South Americans in arrests, Hispanic ethnicities were grouped together.

Age at the time of survey administration was calculated using the respondent's reported date of birth. Respondents were asked whether they were born in the USA and, if not, when they moved to the USA. These variables were used to calculate the number of years the respondent had been in the USA. Respondents were asked to report how old they were when they moved to their current residence; their age was used to calculate the number of years they had lived in their current residence. The interviewer noted the respondent's gender.

Delinquent Behaviors

A robust set of delinquency measures were constructed from data provided during the waves I and IV in-home questionnaires, including property crime, violent crime, drug crime, youth delinquency (wave I only), school truancy (wave I only), alcohol use, and marijuana use. In accordance with previous studies using Add Health data ( Felson and Deane 2007 ; McNulty and Bellair 2003 ), items from the property crime, violent crime, drug crime, and youth misbehaviors scales (“ Appendix 1 ”) were re-coded as 1 (yes) or 0 (no) and averaged. Truancy in wave I was constructed using the question “During this school year, how many times have you skipped school for a full day without an excuse?” Categories were defined based on the distribution of response (0, 1–9, or 10 or more), and a category was created for those who reported not currently being in school.

Wave I alcohol use was constructed from three questions asking about the timing and frequency of use; responses were constructed to create four mutually exclusive categories: those who (a) had never had a drink of alcohol, (b) those who had tried alcohol, but had not consumed any in the past year, (c) those who had consumed in the past year, but had never had 5 or more drinks in a row (binge drinking), and (d) those reporting binge drinking at least once in the past year. For wave IV, responses were used to identify respondents who: (a) had never had a drink of alcohol, (b) those who had consumed in the past year, but had never binge drank, (c) those who binge drank less than once a month, and (d) those who binge drank once a month or more. Marijuana use in wave I was constructed from three questions asking about the timing and frequency of use; responses were constructed to identify those who: (a) had never tried marijuana, (b) had tried marijuana, but had not used in the past 30 days, and (c) had used in the past 30 days. For wave IV, responses were used to identify respondents who had used marijuana in the past year and those who had not.

Educational Factors

School connectedness was measured using five items which asked about student perceptions during the current school year or, if it was summer, the previous school year. Items were designed to capture the social belonging dimension of school connectedness (e.g., “you feel close to people at your school”) and have demonstrated acceptable internal consistency ( Joyce and Early 2014 ). Responses, each ranked on a five-point scale (ranging from 1 “strongly disagree” to 5 “strongly agree”), were averaged, and four categories were created. Educational attainment was constructed using responses to the wave IV in-home questionnaire that asked participants to indicate “the highest level of education that you have achieved to date.” Responses were categorized as “less than high school,” “high school graduate or GED,” “some college,” or “completed a bachelor's degree or higher.”

Home Characteristics

All home characteristics were constructed using the wave I parental in-home questionnaire. The number of adults living in the home was defined as one or two. Two adults were counted as living in the home if the parental respondent was married and living with the spouse; married, not living with the spouse, but living in a marriage-like relationship with someone else; or not married, but living in a marriage-like relationship. Parent education level was coded as the highest level of education completed by either adult living in the house. Household income was categorized based on response to the question “about how much total income, before taxes did your family receive.” A separate indicator was constructed to indicate refusals. Finally, parental relationship with youths was constructed by averaging responses to four items on relationship strength and quality (e.g., “you get along well with [child], you make decisions about [child's] life together”) in accordance with previous studies ( Johnson 2013 ) and dichotomized as weak (1.0–4.0) or strong (>4.0) based on the distribution of responses. For all home characteristic variables, because of the large number of respondents (10.6 %) for which no in-home questionnaire was completed, an indicator was created to specify that no parental interview was conducted (to retain these respondents in the multivariable analyses).

School Characteristics

All school characteristics were constructed using the wave I school administrator questionnaire. School type was coded as “comprehensive public school (not including magnet school or school of choice),” “public magnet school or public school of choice,” “area vocational school or other technical or vocational school,” or “religious or non-religious private school.” School size was coded as small (1–400 students), medium (401–1000 students), or large (1001–4000 students), for both middle and high schools. Average daily attendance was constructed using the original scale reported by school administrators—95 % or more, 90–94 %, 85–89 %, 80–84 %, or 75–79 %. The number of school-based services was constructed by summing the number of 18 services (athletic physical, non-athletic physical, treatment for minor illness and injuries, diagnostic screening, treatment for sexually transmitted diseases, immunizations, family planning counseling, family planning services, prenatal/postpartum health care, drug awareness and resistance education program, drug abuse program, alcohol abuse program, nutrition/weight loss program, emotional counseling, rape counseling program, physical violence program, day care for children of currently enrolled students, and physical fitness/recreation center) provided “on school premises.” Finally, school discipline policy was constructed by averaging the number of first-time offenses (for cheating, fighting with another student, injuring another student, possessing alcohol, possessing an illegal drug, possessing a weapon, drinking alcohol at school, using an illegal drug at school, smoking at school, verbally abusing a teacher, physically injuring a teacher, stealing school property) that resulted in an “out of school suspension” or “expulsion.”

Community Characteristics

All community characteristics were constructed using the wave I contextual file. Crime rate was the total crime rate per 100,000 population, as obtained from the Uniform Crime Reports; county-level counts of arrests and offenses for the violent crimes of murder, rape, robbery, and violent assault, and the property crimes of burglary, larceny, auto theft, and arson are provided to the US Federal Bureau of Investigation by local agencies. Poverty rate (the proportion of families with income in 1989 below the poverty level), unemployment rate (for the general population), the proportion of individuals who were white, and the proportion of housing units vacant were derived from the 1990 Census long-form questionnaire. With the exception of crime rate (only available at the county level), all variables were at the census block group level.

Analytic Methods

Bivariate analyses were first conducted to examine the association between race/ethnicity and the other individual, home, school, and community characteristics. To examine the two primary research questions, cross-sectional multilevel logistic regression was conducted using arrest (yes or no) as the dependent variable. Sets of predictor variables were sequentially added to create six versions of the model: (1) model 1, the base model, which included only race/ethnicity; (2) model 2, which included race/ethnicity along with individual characteristics and measures of delinquency; (3) model 3, which included all variables from model 2, plus home characteristics; (4) model 4, which included all variables from model 3, plus school characteristics; (5) model 5, which included all variables from model 3, plus community characteristics; and (6) model 6, which included all individual, home, school, and community characteristics. Across models, individual, home, and community variables were treated as level one variables, while school characteristics (the primary sampling unit) were treated as level two variables.

Multidegree of freedom tests were conducted in order to examine the significance of categorical variables (with more than two levels) as well as “groups” of home, school, and community characteristics. To judge magnitude of effects, predicted values and differences were computed using Taylor series standard errors to evaluate significance. All analyses were completed using the individual- and school-level weights provided by the survey developers in order to properly account for the study design. Due to the complexity of the multivariable models, all analyses were performed using cases with complete data for all variables of interest (86.2 % of the total sample). All analyses were conducted using Stata version 14.1 ( StataCorp LP, College Station, Texas ). All materials were reviewed and approved by the Los Angeles County Department of Public Health Institutional Review Board.

Descriptive Statistics

More than a quarter of respondents (29.6 %) reported having ever been arrested ( Table 1 ). There were significant differences in arrests between racial/ethnic groups, with 36.8 % of blacks, 30.3 % of Hispanics, and 27.9 % of whites having ever been arrested. Among those who had been arrested, 26.1 % reported having been arrested before the age of 18 and 50.7 % reported having been arrested more than once. The most commonly reported reasons for the first arrest included alcohol or drug-related offenses (46.0 %), theft or robbery (12.0 %), and violent offenses (e.g., assault, forcible rape) (10.3 %).

Characteristics of the full sample and characteristics stratified by race/ethnicity

There were a number of differences among racial/ethnic groups for many of the observed individual, home, school, and community characteristics ( Table 1 ). For example, whites reported the highest level of alcohol use at both wave I and wave IV and marijuana use at wave IV, in comparison with other groups. Differences among racial/ethnic groups with regard to property crime at wave I were detected, with Hispanics having higher levels than whites and blacks. Both blacks and Hispanics had higher levels of violent crime than whites at wave I. Blacks also reported higher levels of violent crime than whites at wave IV. Whites reported the highest levels of educational attainment, with 33.3 % having completed college, compared to 24.3 % of blacks and 19.6 % of Hispanics.

White respondents had the highest proportion of parents complete an interview and were more likely than other racial/ethnic groups to have two parents living in the house at wave I—82.5 % of whites had two parents in the home, compared to 66.0 % of blacks and 76.9 % of Hispanics. White parents reported having higher levels of educational attainment and higher household incomes, for example, 12.8 % of white parents reported an annual household income over $80,000, compared to 4.9 % of Hispanics and 4.7 % of blacks. With regard to schools, black youths were more likely to go to a school that reported lower levels of average daily attendance and more strict suspension policies, when compared to other racial/ethnic groups. Looking at community characteristics, both blacks and Hispanics lived in areas with more crime, family poverty, unemployment, and vacant housing, for example, the average family poverty rate at wave I for whites was 0.09 compared to 0.23 for blacks and 0.15 for Hispanics. In general, white youths were more likely to live in an area highly concentrated with white residents, while black and Hispanic youths lived in areas with lower concentrations of white residents ( Table 1 ).

Multivariable Analyses

To what extent are racial/ethnic differences in arrest explained by differences in delinquent behaviors.

Results of the multivariable analyses suggest that racial/ethnic differences in arrest were not explained by differences in individual-level delinquent behaviors. After controlling for demographic characteristics, including gender, age, time in the USA, time in current residence, and region, as well as a range of delinquent and criminal behaviors (model 2), there were significant racial/ethnic differences in arrests. After controlling for these factors, the odds of being arrested increased among blacks, as compared to whites, from 1.40 (95 % confidence interval [CI] = 1.18, 1.68) (model 1) to 1.58 (95 % CI = 1.27, 1.95) (model 2). Other significant predictors associated with increased odds of arrest included male gender, having lived longer in the USA, having lived for a shorter time in one's current residence, educational attainment, and delinquent behavior, including property crime (in wave IV), violent crime (in both waves), drug crime (in both waves), truancy, and drug and alcohol use (in wave IV). Largest effect sizes were observed for gender, property and violent crime at wave IV, and educational attainment ( Table 2 ).

Results of multilevel logistic regression: factors associated with ever being arrested among a national sample of adolescents and young adults

Data from the National Longitudinal Study of Adolescent to Adult Health

h Average of five items (“ Appendix 1 ”)

Adding home characteristics (model 3) did not significantly alter the association between race/ethnicity and the odds of being arrested. In this model, the association between most of the demographic characteristics, delinquent behaviors, and educational factors and the odds of arrest remained similar in both strength and magnitude. As a group, the parental variables were shown to be associated with the odds of arrest ( X 2 = 2962.0, p < 0.0001). In particular, parent's relationship with their child was a strong predictor of arrest; respondents whose parent reported a weak relationship with him/her had 1.26 the odds of arrest (95 % CI = 1.09, 1.46), compared to those whose parent reported a strong relationship ( Table 2 ).

What Aspects of Community and School Environments are Associated with Racial/Ethnic Differences in Arrests?

Multivariable analyses suggest that neighborhood composition (the percent of white residents in the neighborhood) was the primary driver of racial/ethnic differences in arrests. In model 6, for every one percentage point increase in the proportion of individuals in a community who were white, respondents had less than half the odds of being arrested (odds ratio = 0.44, 95 % CI = 0.16, 0.69), after controlling for other factors. The predicted probability of arrest among whites was 0.29 (95 % CI = 0.27, 0.31), while the predicted probability among blacks was 0.30 (95 % CI = 0.26, 0.33); this difference was not statistically significant ( p = 0.58). While other school characteristics (model 4 joint F test of school characteristics X 2 = 41.33, p < 0.0001) and community characteristics (model 5 joint F test of community characteristics X 2 = 13.78, p = 0.0171) were associated with the odds of being arrested, they were not the primary drivers of racial/ethnic disparities ( Table 2 ). When model 6 was stratified by race/ethnicity, results suggested that the relationship between neighborhood composition and arrest differed by race/ethnicity, although there were few whites who lived in areas with a low concentration of white residents and few blacks who lived in areas with a high concentration of white residents. Specifically, as the percent of whites increased, the odds of arrest among whites (odds ratio = 0.20, 95 % CI = 0.08, 0.47) and other races (odds ratio = 0.20, 95 % CI = 0.03, 1.42) decreased, whereas the odds of arrest among blacks (odds ratio = 1.10, 95 % CI = 0.53, 2.25) and Hispanics (odd ratio = 0.95, 95 % CI = 0.25, 3.63) remained fairly constant.

Despite well-documented racial/ethnic differences in rates of contact with the justice system, reasons for these disparities remain unclear. This study sought to examine the extent of racial/ethnic differences in arrests among a national sample of adolescents and young adults to better understand the extent to which these differences were influenced by delinquent behavior as well as a range of other individual, home, school, and community characteristics. Overall, analyses showed significantly higher likelihood of having ever been arrested among blacks, when compared to whites, even after accounting for a range of delinquent behaviors. Importantly, after controlling for racial composition of the neighborhood, these disparities were no longer present, suggesting the importance of neighborhood context in influencing racial/ethnic disparities in arrests.

Results of the present study align with the well-documented disparities in arrests between blacks and whites ( Puzzanchera and Hockenberry 2015 ). As expected, both youth and adult delinquent behaviors—including property crime, violent crime, drug use, drug-associated crime, and truancy—were significantly, positively associated with the likelihood of arrest. While rates of delinquent behavior were fairly consistent across racial/ethnic groups, some differences were noted, for example, blacks reported higher rates of involvement in violent crime in both youth and adulthood, when compared to whites, supporting previous research ( Felson and Deane 2007 ; McNulty and Bellair 2003 ). In the present study, however, the vast majority of delinquent behaviors did not differ between racial/ethnic groups, and whites showed higher rates of some forms of delinquency, including alcohol and marijuana use. Results support criticisms raised about the “war on drugs,” wherein racial/ethnic minorities have experienced significantly higher rates of arrests for drug offenses, despite comparable rates of drug possession and sales ( Fellner 2009 ). In the present study, after controlling for delinquent behaviors, the magnitude of the disparity in arrests between blacks and whites remained significant, suggesting that observed differences in arrests were not driven by differences in delinquent behaviors. Instead, these results support the growing body of research demonstrating the importance of contextual variables in driving disproportionate minority contact with the justice system ( Crutchfield et al. 2012 ; Huizinga et al. 2007 ; Kirk 2008 )

Results of the present study suggest that neighborhood racial composition may be one of the key factors driving racial/ethnic disparities in arrest rates. Historically, people of color have been concentrated into areas that differ vastly in their level of economic, social, and political resources, including the quality of educational and employment opportunities, the level of poverty and family disruption, and other neighborhood resources ( Krivo et al. 2009 ; Williams 1997 ; Williams and Collins 2001 ); such spatial inequality has been recognized as an important contributor to neighborhood disorganization and crime ( Cullen and Agnew 2011 ; Sampson 2013 ). The current level of residential racial segregation and the concentration of poverty in the USA is the product of structural forces, political decisions, and institutional arrangements, many of which continue to operate today ( Jargowsky 2015 ). In the present study, both blacks and Hispanics tended to live in communities with higher rates of crime, poverty, and unemployment, when compared to whites. While many aspects of school and community contexts were associated with arrest, results of the present study point to the important role of neighborhood racial composition in influencing racial/ethnic disparities in arrest, above and beyond socioeconomic indicators of poverty, unemployment, vacant housing, or school quality.

Associations between neighborhood racial composition and the likelihood of arrest may reflect differences in criminal justice practices and policies, such as police presence. Previous studies have shown racial composition to be related to police force size ( Parker et al. 2005 ) and police behaviors ( Petrocelli et al. 2003 ; Renauer 2012 ). In the present study, whether the observed association between neighborhood racial composition and arrest is rooted in a consensus (race neutral) or conflict (social control), theoretical perspective cannot be fully determined. The statistically significant association between racial composition and the odds of arrest, after accounting for crime rates, provides some support for the role of social control. If policing practices are driven by a uniform desire to reduce disorder, then controlling for differences in crime rates should decrease the magnitude of racial/ethnic disparities in arrest; however, such results were not seen in the present study. This study is limited, though, in its measures of crime, which was not available at the neighborhood level, where “hot spots” for crime and association problem-oriented policing may be determined.

A somewhat unexpected finding was the lack of evidence supporting differences in arrests between Hispanics and whites. While Hispanics are often considered to be at higher risk for police contact, previous studies have been mixed, finding both positive ( Vazsonyi and Chen 2010 ) and null ( Anderson 2015 ; Tapia 2010 ) associations. Reasons for these contradictory findings remain unclear, but could be related to the fact that Hispanic ethnicity may be not be as readily discernible a characteristic as race by law enforcement officials ( Tapia 2010 ). In addition, Hispanics represent a heterogeneous group of backgrounds and many previous studies have been unable to examine differences among Hispanic subgroups. While preliminary analyses in the present study did not find differences in arrests among those who reported being of Mexican, Cuban, Puerto Rican, or Central/South American descent, a more in-depth exploration of these and other Hispanic groups represents an important area for future research. As results of the present and previous studies ( Kirk 2008 ) suggest the potentially protective role of being a recent immigrant, nativity should also be considered. Unfortunately, the small number of recent immigrants included in the present study sample prevented in-depth exploration of these issues.

Although this study is one of the first to examine an expansive range of individual, home, school, and community characteristics in influencing arrests among a national sample of adolescents and young adults, it has a number of limitations. First, data from youths, family members, and school administrators were collected through self-report. While self-reported measures of delinquency are not as ideal as objective measures, previous studies suggest that such methods are still reliable and valid ( Thornberry and Krohn 2003 ) and that self-reporting of arrest does not vary systematically by race ( Pollock et al. 2015 ). Second, because of the small number of respondents, individuals who identified as Asian or Pacific Islander, American Indian or Native American, or other were combined into one category. Third, because of the complexity of the statistical model, complete case analysis was used. To help address some instances of item non-response, indicators were created for missing values (e.g., for income and whether the youth had a parental interview). To the extent that other variables are not missing at random, then results might be biased. Fourth, while the dataset provided information on a vast array of constructs, some were measured using only a single question (e.g., truancy, drug crime). In addition, no direct measures of law enforcement behaviors and practices or neighborhood measures of collective efficacy or social disorganization were available, making it difficult to articulate the specific mechanisms underlying the association between neighborhood composition and arrest. Moreover, because few white youths in the sample lived in areas with a low concentration of white residents and few black youths lived in areas with a high concentration of white residents, it was difficult to fully examine differential effects of neighborhood composition. Fifth, since Add Health is a school-based sample, individuals who are disconnected from school may be underrepresented. Finally, while the use of national-level data provides a generally representative picture, this study could not examine state- or city-level variations in the factors most likely to influence disparities in arrest.

Despite these limitations, this study provides insights on an issue that has vexed the US juvenile and criminal justice systems. Disproportionate rates of minority contact are a longstanding problem that has neither been well understood nor effectively addressed. Results underscore emerging research supporting the need to look beyond the role of individual behaviors, to instead target the underlying contextual factors—particularly neighborhood racial composition—that drive racial/ethnic disparities in justice system contact.

The deleterious health, social, and economic consequences created for low-income people of color as a result of contact with the justice system are closely intertwined ( My Brother's Keeper Task Force 2015 ). By looking further upstream to better elucidate the social, economic, and other contextual factors—such as arrest—that drive health disparities, researchers, policymakers, and agency decision-makers can take a more holistic approach. Given its range of negative impacts, additional efforts to reduce disproportionate minority contact with the justice system may provide a potential lever to foster more equitable outcomes among our nation's most vulnerable communities.

Acknowledgments

The authors thank Dr. Xiao Chen from the University of California, Los Angeles Center for Health Policy Research and staff from the from the University of California, Los Angeles Institute for Digital Research and Education for their statistical support.

Funding This work was supported in part by grants from the National Institutes of Health/National Center for Advancing Translational Science, University of California, Los Angeles Clinical Translational Science Institute [Grant Number: TL1TR000121]. This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill and funded by Grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due to Ronald R. Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health Web site ( http://www.cpc.unc.edu/addhealth ). No direct support was received from grant P01-HD31921 for this analysis.

See Table 3 .

National Longitudinal Study of Adolescent to Adult Health in-home survey questions used to measure delinquency

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Hypothesis Testing in Law and Forensic Science: A Memorandum

Forensic Commentary Series

• David H. Kaye
• See full issue

This Forum Commentary series presents views on a memorandum from a group of lawyers and judges advising the Organization of Scientific Area Committees for Forensic Science (OSAC). 1 In response to calls for improving the practices of forensic science, 2 the National Institute of Standards and Technology (NIST) created the Scientific Area Committees in 2014 to promote and develop standards “that are fit-for-purpose and based on sound scientific principles.” 3 The memorandum from the Legal Resource Committee (LRC) 4 responds to a question from a scientist on OSAC’s governing board about whether the criminal law’s concern with avoiding false convictions at the expense of false acquittals should affect the choice of a “significance level” for deciding whether pieces of glass match in their chemical composition (and hence might have a common origin). Must a criminalist favor the hypothesis that similarities are coincidental over the hypothesis that the fragments have a common origin? The underlying issue applies to many forms of identification evidence, including fingerprints, fibers, paint chips, bullets, and biological fluids. Indeed, arguments over the choice of a significance level arise for statistical evidence of all sorts, from econometrics to epidemiology. 5

This Introduction is a preamble to the memorandum. Part I describes the technical standard that prompted the memorandum. Part II sketches the statistical ideas in the memorandum by using glass comparisons to illustrate the three main statistical approaches to reasoning about the implications of evidence. This Introduction is followed by the memorandum itself and two commentaries.

* Associate Dean for Research and Distinguished Professor of Law, Penn State Law. This Introduction benefited from discussions with José Almirall, Karen Kafadar, and members of the Legal Resource Committee (LRC) of the Organization of Scientific Area Committees for Forensic Science (OSAC). The views expressed here are the author’s. They should not be attributed to NIST, OSAC, the LRC, or any other individual or organization.

^ See Memorandum from the Legal Res. Comm. to the Org. of Sci. Area Comms. for Forensic Sci., Nat’l Inst. of Standards & Tech., Question on Hypothesis Testing in ASTM 2926-13 and the Legal Principle that False Convictions Are Worse than False Acquittals 6 (rev ed. Oct. 7, 2016), reprinted in 130 Harv . L . Rev. F . 137 (2017) [hereinafter LRC Memo].

^ See, e.g. , Comm. on Identifying the Needs of the Forensic Sci. Cmty ., Nat’l Research Council, Strengthening Forensic Science in the United States: A Path Forward 53 (2009).

^ About OSAC , OSAC Newsletter (Nat’l Inst. of Standards & Tech., Gaithersburg, Md.), Oct. 2015, at 3, 3, https://www.nist.gov/sites/default/files/documents/forensics/OSACNewsLetterOctober2015.pdf [ https://perma.cc/29QA-XRJC ].

^ When the memorandum was written, the LRC was composed of ten individuals from prosecutor and public defender offices, the judiciary, the Innocence Project, and law school faculty. The LRC comments on proposed standards and advises OSAC on legal issues. The scientific committees need not follow the LRC’s recommendations or give effect to its opinions. OSAC-approved standards go to private standards-development organizations for possible adoption (perhaps with modifications). If OSAC approves of standards adopted by these external groups, NIST incorporates them into a registry of approved standards. For more information about the LRC, see OSAC Roles and Responsibilities , Nat’l Inst. Standards & Tech . (Jan. 26, 2016), https://www.nist.gov/forensics/osac-roles-and-responsibilities [ https://perma.cc/3V99-CJ5L ]. How much influence these standards will have on forensic laboratories, courts, or legislatures remains to be seen.

^ See, e.g. , David H. Kaye et al ., The New Wigmore: A Treatise on Evidence: Expert Evidence § 12.8.3, at 563–64 (2d ed. 2011).

March 10, 2017

More from this Issue

Legal resource committee memorandum.

Question on Hypothesis Testing in ASTM 2926-13 and the Legal Principle that False Convictions Are Worse than False Acquittals

No Room for Error: Clear-Eyed Justice In Forensic Science Oversight

• Erin Murphy

The Burden of Proof and the Presentation of Forensic Results

• Edward K. Cheng

Hypotheticals in the Criminal Law Classroom: An Interview with Lawrence Connell

Ashley Thorne

• February 18, 2011
• Academic Freedom
• Law Schools

Professor Lawrence Connell, who teaches Criminal Law at Widener University, has been placed on administrative leave after students complained about him referring in classroom hypotheticals to killing the university dean, Linda Ammons.  

Some commentators have said that because Dean Ammons is black, his repeated referrals to her death, even for the sake of example, amount to racist and violence-invoking speech. Others argue that law professors use such examples all the time and that this is a normal way to teach a class, as Ann Althouse , a law professor at the University of Wisconsin wrote on her blog, “Look, if you're teaching criminal law, you use hypos that have people doing criminal things. Putting real names in the hypos might be funny or attention-getting or just stupid, but let's not get hysterical.”

Delaware Online quotes Connell’s lawyer saying, of Ammons, “I think she wanted to get rid of a conservative professor.”

We at NAS take an interest in Professor Connell’s case at Widener as one of potential restriction of academic freedom, and we see some cause for concern. We asked Professor Connell some clarifying questions, and he graciously agreed to an interview; below are his answers to our questions. We will continue to follow this case and report as we learn more.

Q: Do you believe that Widener University is seeking to oust you because you are conservative?

Q: Do you have any evidence of this?

A: Yes. This would include, but not be limited to the following:

My political views have been well-known at Widener since at least 2002, when I participated in a law school debate about the Bush-Gore election. While arguing in favor of the Bush domestic policies, I was shouted down by Gore supporters in the audience. After the debate I was asked by the Student Bar Association to apologize to the student body – and refused - for calling belief in Gore’s proposed economic policies “naïve.” I've not been asked to participate in any political debates at Widener since that time.

Since the election of Obama and Biden (an adjunct professor at Widener), the News Journal in Wilmington has published several letters I have submitted, under my signature as a private citizen, and not in my capacity as a professor at Widener. The letters have criticized various aspects of the Obama administration’s agenda on such topics as immigration policy, the ban on deep water drilling, and the demonization of Tea Partiers.

Q: I read this article which tells about your success in saving James Riley from the death penalty - just to clarify, were you his lawyer at the time? If not, what was your official role in the case?

A: In 1986 I was the Director of the law school’s Postconviction Relief Clinic, in which third-year law students assisted me in reviewing the cases of criminals who had been convicted of serious felonies and whose convictions had been affirmed by the Delaware Supreme Court. I was asked to review the case of Mr. Riley, a black man who had been convicted of killing a white victim and upon whom the death sentence was imposed by an all-white jury. Our investigation revealed, among other legal problems, a pattern of racial discrimination in the selection of Mr. Riley’s jury. As a result, I volunteered to represent him to pursue, among other issues, what appeared to be a violation of Mr. Riley’s constitutional right to equal protection of the law in the selection of his jury.

After twice having our issues rejected by the state courts, we took Mr. Riley’s case to the federal courts. There, two attorneys from a prominent law firm joined me in representing Mr. Riley, and assumed the role of lead counsel in the federal litigation. Because of the relationship I had developed with Mr. Riley while representing him in the state courts, I continued my representation in the federal courts in the role of his co-counsel. In 2002, nearly sixteen years after I initially developed Mr. Riley’s equal protection claim, a majority of the Third Circuit Court of Appeals, by a slim 6 to 5 margin, agreed that Mr. Riley had indeed suffered unlawful discrimination in the selection of his jury, and overturned his conviction and death sentence.

During the early years of my work for Mr. Riley, when his case was in the state system, his execution repeatedly was rescheduled and I repeatedly was required to seek stays on his behalf. Each time a new execution date was scheduled, I found myself in the impossibly difficult position of trying to console and provide hope to a man whose execution was imminent.

Making the entire situation of my representing Mr. Riley even more difficult for me was the fact that the sister of Mr. Riley’s victim, himself a widower who was survived by his five minor children, was my sister’s life-long best friend. My sister’s best friend had undertaken the care of the victim’s youngest daughter. Choosing to represent Mr. Riley presented quite a difficult personal dilemma for me, but Mr. Riley’s execution resulting from an unlawfully selected jury would not balance the scales of justice. It would simply compound the senseless loss of life.

For details of the intricate procedural posture of Mr. Riley’s case, as well as the reasoning for overturning his conviction and death sentence, please see the Third Circuit’s decision at http://openjurist.org/277/f3d/261/james-william-riley-v-stanley-w-taylor

Q: In your courses, do you use other names that students would know (i.e., individuals at the University) in your hypotheticals?

Q: Was there a particular reason you chose to refer to Linda Ammons as opposed to someone else?

A: Yes. This would include, but not be limited to the following: People need to understand the nature of a law school criminal law class, and how different it is from other types of classes, even other types of law school classes. Professor Orin Kerr of George Washington University School of Law describes it well in http://volokh.com/2011/02/16/criminal-law-professor-suspended-for-classroom-hypotheticals/

“One of the common ways that law professors keep students mildly entertained in class is by posing hypotheticals involving their professors and the Dean. I’m not sure why this is so funny, but students just love it. If you teach first-year criminal law, which typically focuses heavily on homicide crimes, that means you spend a lot of time imagining your colleagues meeting horrible fates. If A kills B out of revenge, that’s just a boring hypothetical. But if the hypo involves the students’ Torts Professor killing the Dean out of revenge — or better yet, a conspiracy in which the Dean and the students’ Torts and Contract Professors agree to kill their Criminal law Professor for beer money — well, that’s serious entertainment. It may seem a bit morbid at first. But it’s the opposite, I think. Putting Professors or the Dean in the place of real criminals and real victims makes the scenario so absurd that it adds a bit of levity to what is otherwise a very depressing topic. As a result, it’s a common tool Criminal Law professors use when teaching first-year students the basic doctrines of criminal law. I suppose over the years I’ve murdered pretty much every 1st-year teacher — and certainly all my Deans — and they’ve all murdered me, too. (All during in-class hypos, mind you.)”

Q: Can you give me an example of a hypothetical you might have used in class, to which the students who complained might have been referring? Can you describe the context in which you would have used it?

A: Yes, here is one: The Dean has threatened to fire me if she comes to school one more time and finds that I have parked in her designated parking space. Upset about the possibility of losing both my job and the parking space, I bring my .357 to school, get out of my car, put the .357 into my waistband, walk to the top floor where her office is located, open the door to her office, see her seated at her desk, draw my weapon, aim my weapon, and fire my weapon directly into what I believe to be her head. To my surprise, it’s not the Dean at all, but an ingeniously painted pumpkin - a pumpkin that has been intricately painted to look like the Dean. Dick Tracy rushes in and immediately wrestles me to the ground. I am charged with the attempted murder of the Dean.

The hypothetical raises various issues about attempted crimes that might entail discussion that spans more than one class. Some of the classroom discussion in the first, for example, will address the two basic philosophical problems of why we punish attempts, which are failed efforts at crime, and why we punish attempts less than successfully completed crimes.

A retributive argument, on the one hand, is that the attemptor has demonstrated his moral culpability by his bad conduct, and the degree of his punishment should not depend on a fortuitous turn of luck. On the other hand, a retributivist might argue that punishment in the absence of harm is unjust. For retributive purposes, has Connell demonstrated his moral culpability by shooting what he believes to be the Dean? Or does the fact that he merely destroyed a pumpkin suggest that his punishment would be unjust?

A utilitarian argument is that the attemptor’s actions demonstrate his dangerousness. His dangerousness having been established, the attemptor needs to be incapacitated or else he will try again until he succeeds. On the other hand, a utilitarian might argue that imposing punishment for conduct short of causing actual harm will cloud the otherwise bright line between conduct that is punishable and not punishable. Certainty of punishment enhances deterrence, while reducing certainty detracts from it. Should Connell be punished in order to prevent him from completing his intended result? If Connell’s shooting a pumpkin is considered attempted murder, then where do we draw the line? 

Attempt law also raises questions about the role of law enforcement in a free society. We want police to capture the people who cause harm, yet we also want police to protect us before harm can occur. On the one hand, a free society does not want punish people who only have bad thoughts or criminal tendencies. On the other hand, we do not want the police to wait so long to intervene that the risk of harm may become inevitable. If we allow law enforcement to intervene before harm is committed, where do we draw the line between conduct that is punishable and conduct that is not?

The “ingeniously painted pumpkin” hypo also raises for discussion in a different class the issue of if, and under what circumstances, impossibility may ever be a defense to an attempt charge. The law generally evolved into the rules that legal impossibility is a defense to an attempt charge, while factually impossibility is not.

What is legal impossibility? What is factual impossibility? Is it legally impossible for a shooter to commit attempted murder (if murder is intentionally causing the death of another human being) by intentionally shooting an ingeniously painted pumpkin, rather than a human being? Or is it factually impossible for a shooter to commit attempted murder by intentionally shooting an ingeniously painted pumpkin because shooting a pumpkin cannot cause the death of another human being? Considerable classroom time is devoted to a discussion of various examples and alternative analyses, in trying to resolve the conundrum.  

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Do Presidents Have Immunity? Trump’s Case Explained: QuickTake

By Greg Stohr

The US Supreme Court has never considered whether former presidents are immune from criminal prosecution for acts they took in office. Before Donald Trump , the court never needed to.

The justices are scheduled to hear arguments Thursday in a historic showdown likely to determine whether Trump stands trial in federal court in Washington for allegedly inciting the Jan. 6 Capitol riot and trying to overturn the 2020 election. Trump, fighting charges pressed by Special Counsel Jack Smith , contends the Constitution gives presidents “absolute immunity” from prosecution over official actions taken while in office.

Two lower courts ruled against Trump, saying he was seeking something that couldn’t be found in the Constitution, the words of the nation’s founders or any Supreme Court precedent.

“In this moment, there is no such thing as criminal immunity for presidents,” said Kimberly Wehle , a University of Baltimore law professor whose focuses include the constitutional separation of powers.

Here are some of the issues swirling around the case.

What will be the impact on Trump’s criminal cases?

Trump, the presumptive 2024 Republican presidential nominee, is pressing a sweeping argument that would mean dismissal of the case against him in Washington. The justices could also adopt a narrower version of presidential immunity, potentially kicking the case back to the lower courts to determine whether any of the allegations involve official actions warranting a legal shield.

The timing of the Supreme Court’s ruling may be as important as its substance. Tanya Chutkan , the US district judge overseeing the federal election fraud case against Trump, previously indicated she will give the two sides three months to prepare for a trial that could last two to three months. That makes the window narrow for the immunity question to be resolved and, if the trial goes ahead, for it to finish by Election Day on Nov. 5 so that voters are informed by the outcome.

The case is one of four prosecutions hanging over Trump, including one already proceeding in New York state court over hush-money payments to a porn star. Trump has also claimed presidential immunity in those cases even though many of the allegations involve alleged conduct when he was a private citizen.

What does the Constitution say?

When it comes to presidential immunity, the Constitution doesn’t say anything expressly. As conservative Supreme Court Justice Clarence Thomas noted in a 2020 case involving Trump, “the text of the Constitution explicitly addresses the privileges of some federal officials, but it does not afford the president absolute immunity.”

Trump points to two provisions he says implicitly confer immunity from criminal prosecution. The first is the clause that vests the “executive Power” in the president. Trump says that clause, coupled with broader principles of constitutional separation of powers, mean that federal judges can’t sit in judgment over a president’s official acts.

Smith says the provision implies no such thing, saying that for more than two centuries federal courts have ensured that presidents comply with laws enacted by Congress.

Trump also cites the Constitution’s impeachment judgment clause, which says that a president can be prosecuted after being impeached and convicted. Trump argues that, since he was acquitted in the Senate after the House impeached him for inciting the Jan. 6 Capitol attack, he can’t be prosecuted.

Smith says Trump’s reading turns the impeachment judgment clause upside down. The provision, he says, is designed to ensure a president can be prosecuted after a Senate conviction and doesn’t suggest a president can’t be prosecuted in other circumstances.

What historical parallels are there?

Trump is the first former US president to be indicted, so there are no exact parallels. But two other presidents faced the serious prospect of criminal charges over the past 50 years.

The first was Richard Nixon , who resigned in disgrace in 1974 after the Watergate scandal. A month later, President Gerald Ford pardoned Nixon, saying the ex-president “has become liable to possible indictment and trial for offenses against the United States.” Nixon accepted the pardon the same day.

The second was Bill Clinton . As he was leaving office in 2001, Clinton reached a deal with independent counsel Robert Ray to head off a possible indictment for giving false testimony about his sexual relationship with White House intern Monica Lewinsky .

What are the key legal precedents?

Perhaps the most important precedent is the Supreme Court’s 1982 Nixon v. Fitzgerald ruling, which said former presidents have complete immunity from civil lawsuits for actions taken within the “outer perimeter” of their official duties. Trump is urging the court to extend the Fitzgerald ruling to protect a president from criminal charges as well.

Other important cases include:

• Marbury v. Madison (1803). Though it’s best known for establishing the power of the Supreme Court to strike down federal laws as unconstitutional, Trump argues that Marbury also provides criminal immunity because it says a president’s official acts “can never be examinable by the courts.” A federal appeals court rejected that argument, saying Chief Justice John Marshall was referring to issues that the Constitution puts within the president’s discretion.
• Trump v. Vance (2020). In a 7-2 defeat for Trump, the court ruled that even a sitting president isn’t categorically immune from a state criminal subpoena. The ruling paved the way for a New York grand jury to see Trump’s financial records.
• US v. Nixon (1974). In a precursor to the Vance ruling, the court unanimously ruled that sitting presidents don’t have a total shield from federal criminal process — in that case, a subpoena for secret White House recordings. The ruling led to President Nixon’s resignation after the tapes were released publicly.
• Clinton v. Jones (1997). In another unanimous decision, the Supreme Court ruled that President Clinton had to defend against a civil lawsuit alleging sexual harassment rather than postpone the case until he left office.

Do the leaders of other countries have immunity?

In a number of countries , presidents, prime ministers or chancellors are shielded from liability when performing their governmental duties but can be tried for crimes related to other actions. In France, presidents can’t be sued or prosecuted in a criminal case until after leaving office. That happened to former Presidents Jacques Chirac and Nicolas Sarkozy , mainly for actions that occurred before or after their terms.

In Italy, a government minister including the prime minister can be prosecuted for crimes committed in office only if Parliament approves. Likewise, the German Parliament can lift immunity at the request of prosecutors for legislators, the president or the chancellor (who has immunity only if he or she is a member of Parliament).

Nigeria, Ghana and Kenya protect their presidents against prosecution for criminal and civil offenses only while still in office. In South Korea, a sitting president has immunity unless impeached by Parliament; that’s how Park Geun-hye became that nation’s first top leader removed from office, convicted of corruption charges and later pardoned.

The Reference Shelf

• Keep up with Trump’s trials using Bloomberg’s tracker .
• Related QuickTakes on the hush money case against Trump and how his criminal cases test the US Constitution .
• Bloomberg Opinion’s Noah Feldman explores the immunity arguments .

--With assistance from Gaspard Sebag , Donato Paolo Mancini , Karin Matussek , Moses Mozart Dzawu , Anthony Osae-Brown , Helen Nyambura and Katarina Höije .

To contact the reporter on this story: Greg Stohr in Washington at [email protected]

To contact the editors responsible for this story: Joel Weber at [email protected]

Lisa Beyer, Elizabeth Wasserman

© 2024 Bloomberg L.P. All rights reserved. Used with permission.

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President Biden signs law to ban TikTok nationwide unless it is sold

Bobby Allyn

President Biden has signed a law that gives ByteDance up to a year to fully divest from TikTok, or face a nationwide ban. Kiichiro Sato/AP hide caption

President Biden has signed a law that gives ByteDance up to a year to fully divest from TikTok, or face a nationwide ban.

President Biden on Wednesday signed a law that would ban Chinese-owned TikTok unless it is sold within a year.

It is the most serious threat yet to the video-streaming app's future in the U.S., intensifying America's tech war with China.

Still, the law is not expected to cause any immediate disruption to TikTok, as a forthcoming legal challenge, and various hurdles to selling the app, will most likely cause months of delay.

The measure was tucked into a bill providing foreign aid for Israel, Ukraine and Taiwan. The law stipulates that ByteDance must sell its stake in TikTok in 12 months under the threat of being shut down.

U.S. bans noncompete agreements for nearly all jobs

The move is the culmination of Washington turning the screws on TikTok for years.

Chinese tech giant ByteDance, in 2017, purchased the popular karaoke app Musical.ly and relaunched the service as TikTok. Since then, the app has been under the microscope of national security officials in Washington fearing possible influence by the Chinese government.

Despite concerns in Washington, TikTok has soared. It has become the trendsetter in the world of short-form video and is used by 170 million Americans, which is about half of the country. It is where one-third of young people get their news, according to Pew Research Center.

Trump to score additional $1.2 billion windfall thanks to his Truth Social app

Yet lawmakers and the Biden administration argue that as long as TikTok is owned by a Chinese company, it is beholden to the dictates of China's authoritarian regime

"Congress is not acting to punish ByteDance, TikTok or any other individual company," said Democratic Sen. Maria Cantwell, who chairs the Senate Commerce Committee, in remarks on the Senate floor Tuesday afternoon.

"Congress is acting to prevent foreign adversaries from conducting espionage, surveillance, maligned operations, harming vulnerable Americans, our servicemen and women, and our U.S. government personnel."

In a video posted to the platform soon after Biden signed the bill, TikTok CEO Shou Zi Chew said he is confident TikTok would win in court, adding that users should not expect issues with the app in the meantime.

"Rest assured, we aren't going anywhere," Chew said. "The facts and the Constitution are on our side and we expect to prevail again."

Google worker says the company is 'silencing our voices' after dozens are fired

Tiktok plans to take biden administration to court over the law.

If not sold within a year, the law would make it illegal for web-hosting services to support TikTok, and it would force Google and Apple to remove TikTok from app stores — rendering the app unusable with time.

It marks the first time the U.S. has passed a law that could trigger the ban of a social media platform, something that has been condemned by civil liberties groups and constitutional scholars.

TikTok has vowed to take the Biden administration to court, claiming the law would suppress the free speech of millions of Americans.

The sentiment was echoed by Kate Ruane, who runs the Center for Democracy & Technology's Free Expression Project, who said the law is unconstitutional and a blow to free expression in the U.S.

"Congress shouldn't be in the business of banning platforms," Ruane said. "They should be working to enact comprehensive privacy legislation that protects our private data no matter where we choose to engage online."

Selling TikTok won't be so easy

Any company, or set of investors, angling to purchase TikTok would have to receive the blessing of the Chinese government, and officials in Beijing have strongly resisted a forced sell.

In particular, ByteDance owns the engine of TikTok, its hyper-personalized algorithm that pulls people in and keeps them highly engaged with their feed.

Chinese officials have placed content-recommendation algorithms on what is known as an export-control list, meaning the government has additional say over how the technology is ever sold.

Law took TikTok by surprise

By almost any measure, the law passed rapidly, and it caught many inside TikTok off guard, especially because the company had just breathed a sigh of relief.

Last month, the House passed a bill to compel TikTok to find a buyer, or face a nationwide ban, but the effort stalled in the Senate.

The legislation gave TikTok a six-month window to find a buyer, which some senators said was too little time.

A new push, this time attaching the divest-or-be-banned provision to foreign aid, fasted-tracked the proposal. It mirrors last month's attempt, but it extends the sell-by deadline, now giving TikTok nine months to find a buyer, with the option of a three-month extension if a potential acquisition is in play.

Sen. Markey: 'American companies are doing the same thing'

Lawmakers from both parties have argued that TikTok poses a national security risk to Americans, since the Chinese government could use the app to spy on Americans, or influence what U.S. users see on their TikTok feeds, something that has gained new urgency in an election year.

But some have pushed back, including Democratic Sen. Edward Markey of Massachusetts. He said on the Senate floor on Tuesday that there is "no credible evidence" that TikTok presents a real national security threat just because its parent company is based in China.

National intelligence laws in China would require ByteDance to hand over data on Americans if authorities there sought it, but TikTok says it has never received such a request.

Markey said concerns about digital security, the mental health of young people and data privacy should be addressed with comprehensive legislation encompassing the entire tech industry, not just TikTok.

"TikTok poses a serious risk to the privacy and mental health of our young people," Markey said. "But that problem isn't unique to TikTok and certainly doesn't justify a TikTok ban," he said. "American companies are doing the same thing, too."

Justices Seem Ready to Limit the 2020 Election Case Against Trump

Such a ruling in the case, on whether the former president is immune from prosecution, would probably send it back to a lower court and could delay any trial until after the November election.

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Charlie Savage and Alan Feuer

Charlie Savage reported from Washington, and Alan Feuer from New York.

Here are four takeaways from the Supreme Court hearing on Trump’s claim to immunity.

The Supreme Court heard arguments on Thursday about Donald J. Trump’s claim that the federal charges accusing him of plotting to overturn the 2020 election must be thrown out because he is immune from being prosecuted for any official act he took as president.

Here are some takeaways.

Several justices seemed to want to define some level of official act as immune.

Although Mr. Trump’s claim of near-absolute immunity was seen as a long shot intended primarily to slow the proceedings, several members of the Republican-appointed majority seemed to indicate that some immunity was needed. Some of them expressed worry about the long-term consequences of leaving future former presidents open to prosecution for their official actions.

Among others, Justice Brett Kavanaugh compared the threat of prosecution for official acts to how a series of presidents were “hampered” by independent counsel investigations, criticizing a 1984 ruling that upheld a now-defunct law creating such prosecutors as one of the Supreme Court’s biggest mistakes. Chief Justice John G. Roberts Jr. criticized an appeals court ruling rejecting immunity for Mr. Trump, saying he was concerned that it “did not get into a focused consideration of what acts we are talking about or what documents are talking about.”

“It’s a serious constitutional question whether a statute can be applied to the president’s official acts. So wouldn’t you always interpret the statute not to apply to the president, even under your formulation, unless Congress had spoken with some clarity?” “I don’t think across the board that as serious constitutional question exists on applying any criminal statute to the president.” “The problem is the vague statute — obstruction and 371, conspiracy to defraud the United States can be used against a lot of presidential activities historically with a creative prosecutor who wants to go after a president.” “I think that the question about the risk is very serious. And obviously it is a question that this court has to evaluate. For the executive branch, our view is that there is a balanced protection that better serves the interests of the Constitution that incorporates both accountability and protection for the president.”

The Democrat-appointed justices — Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson — asked questions indicating greater concern about opening the door for presidents to commit official crimes with impunity.

“This is what you’re asking us to say, which is that a president is entitled not to make a mistake — but more than that, a president is entitled for total personal gain to use the trappings of his office. That’s what you’re trying to get us to hold — without facing criminal liability.” “Your honor, I would say three things in response to that. First, the doctrine that immunity does not turn on the allegedly improper motivation or purpose is something that this court has reaffirmed in at least nine or 10 —” “That’s absolute immunity. But qualified immunity does say that whatever act you take has to be within what a reasonable person would do. I’m having a hard time thinking that creating false documents, that submitting false documents, that ordering the assassination of a rival, that accepting a bribe, and countless other laws that could be broken for personal gain, that anyone would say that it would be reasonable for a president or any public official to do that.”

The arguments signaled further delay and complications for a Trump trial.

If the Supreme Court does place limits on the ability of prosecutors to charge Mr. Trump over his official actions, it could alter the shape of his trial.

A decision to send all or part of the case back to the lower courts could further slow progress toward a trial, increasing the odds that it does not start before Election Day.

Of the matters listed in the indictment, some — like working with private lawyers to gin up slates of fraudulent electors — seem like the private actions of a candidate. Others — like pressuring the Justice Department and Vice President Mike Pence to do things — seem more like official acts he took in his role as president.

At one point, Justice Amy Coney Barrett suggested that prosecutors could simply drop Mr. Trump’s arguably official actions from their case and proceed to a swift trial focused only on his private actions. And D. John Sauer, the lawyer for Mr. Trump, told the court that no evidence of Mr. Trump’s official actions should be allowed into the trial.

But Michael R. Dreeben, a Justice Department lawyer arguing on behalf of the special counsel’s office, said the indictment laid out an “integrated conspiracy” in which Mr. Trump took the official actions to bolster the chances that his other efforts to overturn the election would succeed.

He argued that even if the court holds that Mr. Trump has immunity from liability for his official actions, prosecutors should still be allowed to present evidence about them to the jury because the actions are relevant to assessing his larger knowledge and intentions — just as speech that is protected by the First Amendment can still be used as evidence in a conspiracy case.

The hearing revolved around two very different ways of looking at the issue.

Looming over the hearing was a sweeping moral question: What effect might executive immunity have on the future of American politics?

Not surprisingly, the two sides saw things very differently.

Mr. Sauer claimed that without immunity, all presidents would be paralyzed by the knowledge that once they were out of office, they could face an onslaught of charges from their rivals based on the tough calls they had to make while in power. He pictured a dystopian world of ceaseless tit-for-tat political prosecutions that would destroy the “presidency as we know it.”

If a president can be charged, put on trial and imprisoned for his most controversial decisions as soon as he leaves office, that looming threat will distort the president’s decision-making precisely when bold and fearless action is most needed. Every current president will face de facto blackmail and extortion by his political rivals while he is still in office. The implications of the court’s decision here extend far beyond the facts of this case. Could President George W. Bush have been sent to prison for obstructing an official proceeding or allegedly lying to Congress to induce war in Iraq? Could President Obama be charged with murder for killing U.S. citizens abroad by drone strike? Could President Biden someday be charged with unlawfully inducing immigrants to enter the country illegally for his border policies? The answer to all these questions is no.

Envisioning the opposite scenario, Mr. Dreeben worried that any form of blanket immunity would place presidents entirely outside of the rule of law and encourage them to commit crimes, including “bribery, treason, sedition, even murder,” with impunity.

“The framers knew too well the dangers of a king who could do no wrong,” he said.

This court has never recognized absolute criminal immunity for any public official. Petitioner, however, claims that a former president has permanent criminal immunity for his official acts unless he was first impeached and convicted. His novel theory would immunize former presidents for criminal liability; for bribery, treason, sedition, murder and here, conspiring to use fraud to overturn the results of an election and perpetuate himself in power. Such presidential immunity has no foundation in the Constitution. The framers knew too well the dangers of a king who could do no wrong.

Both sides found advocates for their positions on the court.

Justice Samuel A. Alito Jr. clearly seemed worried that without some form of criminal immunity, former presidents would be vulnerable to partisan warfare as their successors used the courts to go after them once they were out of office. And that, he added, could lead to endless cycles of retribution that would be a risk to “stable, democratic society.”

Justice Ketanji Brown Jackson appeared more concerned that if presidents were in fact shielded by immunity, they would be unbounded by the law and could turn the Oval Office into what she described as “the seat of criminality.”

If someone with those kinds of powers, the most powerful person in the world with the greatest amount of authority, could go into office knowing that there would be no potential penalty for committing crimes, I’m trying to understand what the disincentive is from turning the Oval Office into the seat of criminal activity in this country? If the potential for criminal liability is taken off the table, wouldn’t there be a significant risk that future presidents would be emboldened to commit crimes with abandon while they’re in office? It’s right now the fact that we’re having this debate, because O.L.C. has said that presidents might be prosecuted. Presidents from the beginning of time have understood that that’s a possibility. That might be what has kept this office from turning into the kind of crime center that I’m envisioning. But once we say no criminal liability, Mr. President, you can do whatever you want, I’m worried that we would have a worse problem than the problem of the president feeling constrained to follow the law while he’s in office.

What happens next?

There did not seem to be a lot of urgency among the justices — especially the conservative ones — to ensure that the immunity question was resolved quickly. That left open the possibility that Mr. Trump could avoid being tried on charges of plotting to overturn the last election until well after voters went to the polls to decide whether to choose him as president in this election.

And if he is elected, any trial could be put off while he is in office, or he could order the charges against him dropped.

It could take some time for the court to do its own analysis of what presidential acts should qualify for the protections of immunity. And even if the justices determine that at least some of the allegations against Mr. Trump are fair game for prosecution, if they do not issue a ruling until late June or early July, it could be difficult to hold a trial before November.

That would become all but impossible if the court took a different route and sent the analysis back to the trial judge, Tanya S. Chutkan. If Judge Chutkan were ordered to hold further hearings on which of the indictment’s numerous allegations were official acts of Mr. Trump’s presidency and which were private acts he took as a candidate for office, the process could take months and last well into 2025.

Aishvarya Kavi

Reporting from Washington

A spectacle outside the Supreme Court for Trump’s defenders and detractors.

Just as the Supreme Court began considering on Thursday morning whether former President Donald J. Trump was entitled to absolute immunity, rap music started blaring outside the court.

The lyrics, laced with expletives, denounced Mr. Trump, and several dozen demonstrators began chanting, “Trump is not above the law!”

Mr. Trump was not in Washington on Thursday morning — in fact, he was in another courtroom , in New York. But the spectacle that pierced the relative tranquillity outside the court was typical of events that involve him: demonstrations, homemade signs, police, news media, and lots and lots of curious onlookers.

One man, Stephen Parlato, a retired mental health counselor from Boulder, Colo., held a roughly 6-foot-long sign with a blown-up photo of Mr. Trump scowling that read, “Toxic loser.” The back of the sign featured the famous painting by Cassius Marcellus Coolidge of dogs playing poker, adorned with the words, “Faith erodes … in a court with no binding ethics code.” He made the sign at FedEx, he said.

The Supreme Court’s decision to even hear the case, which has delayed Mr. Trump’s election interference trial , was “absurd,” he said.

“I’m a child of the late ’60s and early ’70s and the Vietnam War,” said Mr. Parlato, dressed in a leather jacket and cowboy hat. “I remember protesting that while in high school. But this is very different. I’m here because I’m terrified of the possibility of a second Trump presidency.”

Inside the court, Jack Smith sat to the far right of the lawyer arguing on behalf of his team of prosecutors, Michael R. Dreeben, a leading expert in criminal law who has worked for another special counsel who investigated Mr. Trump, Robert S. Mueller III.

Among those in attendance were Jane Sullivan Roberts, who is married to Chief Justice John G. Roberts Jr., and Ashley Estes Kavanaugh, who is married to Justice Brett M. Kavanaugh.

In an orderly line outside along the side of the court, people were calmly waiting to listen to the arguments from the court’s public gallery. More than 100 people, many of them supporters of Mr. Trump, were in line as of 8:30 a.m. Reagan Pendarvis, 19, who had been waiting there since the middle of the night, said the first person in line had gotten there more than a day before the arguments began.

Mr. Pendarvis, a sophomore at the University of California, San Diego who is living in Washington for the spring semester, was wearing a black suit and bright red bow tie. He said he had been struggling to keep warm since he took his place in line.

Mr. Pendarvis, a supporter of Mr. Trump, said he thought that the cases brought against the former president were an uneven application of the law.

“I think a lot of the cases, especially that happen for Donald Trump, don’t really happen for Democrats on the other side,” he said. “That’s just my take on it.”

David Bolls, 42, and his brother, Jonathan, 43, both of Springfield, Va., also in line for the arguments, also contended that the prosecutions against Mr. Trump were an abuse of judicial power.

“For me, I want to see an even application of justice,” David Bolls said.

For others in line, the Supreme Court’s deliberations were not the main draw. Ellen Murphy, a longtime Washington resident, was trying to sell buttons she designs, though she acknowledged that it was unlikely she would be allowed in with all of her merchandise.

Dozens of the buttons, which said, “Immunize democracy now” and “Trump is toast” over a toaster with two slices of bread, were pinned to a green apron she was wearing.

“We lose our democracy,” Ms. Murphy said, “if the president can do whatever he wants just because he’s president.”

Eileen Sullivan contributed reporting.

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Adam Liptak

What’s next: Much will turn on how quickly the court acts.

The justices heard arguments in the immunity case at a special session, the day after what had been the last scheduled argument of its term. Arguments heard in late April almost always yield decisions near the end of the court’s term, in late June or early July.

But a ruling in early summer, even if it categorically rejected Mr. Trump’s position, would make it hard to complete his trial before the election. Should Mr. Trump win at the polls, there is every reason to think he would scuttle the prosecution.

In cases that directly affected elections — in which the mechanisms of voting were at issue — the court has sometimes acted with unusual speed.

In 2000, in Bush v. Gore, the court issued its decision handing the presidency to George W. Bush the day after the justices heard arguments.

In a recent case concerning Mr. Trump’s eligibility to appear on Colorado’s primary ballot, the justices moved more slowly, but still at a relatively brisk pace. The court granted Mr. Trump’s petition seeking review just two days after he filed it , scheduled arguments for about a month later and issued its decision in his favor about a month after that.

In United States v. Nixon, the 1974 decision that ordered President Richard M. Nixon to comply with a subpoena for audiotapes of conversations with aides in the White House, the court also moved quickly , granting the special prosecutor’s request to bypass the appeals court a week after it was filed.

The court heard arguments about five weeks later — compared with some eight weeks in Mr. Trump’s immunity case. It issued its decision 16 days after the argument , and the trial was not delayed.

Abbie VanSickle

The oral argument lasted nearly three hours, as the justices tangled with a lawyer for the former president and a Justice Department lawyer. A majority of the justices appeared skeptical of the idea of sweeping presidential immunity. However, several of them suggested an interest in drawing out what actions may be immune and what may not — a move that could delay the former president’s trial if the Supreme Court asks a lower court to revisit the issues.

Many of the justices seemed to be considering the idea that presidents should enjoy some form of protection against criminal prosecution. The devil, however, will be in the details: How should that protection extend?

And that question will have profound relevance not only for future presidents, but much more immediately for Donald Trump. The court could decide to draw those rules itself in a broad way for history. Or it could send this case back to a lower court to set the rules of what form immunity could take. If the case is sent back for further proceedings, it could have a dramatic effect on the timing of Trump’s trial, pushing it well past the election in November.

Looking back, one of the main points of discussion turned on the question of which situation would be worse: a world in which presidents, shorn of any legal protections against prosecution, were ceaselessly pursued in the courts by their rivals in a never-ending cycle of political retribution, or allowing presidents to be unbounded by criminal law and permitted to do whatever they wanted with impunity.

Charlie Savage

Sauer, Trump’s attorney, declines to offer a rebuttal. The argument is over.

If the court finds that there is some immunity for official actions, one of the most important questions will be whether prosecutors can still present evidence to the jury of Trump’s official actions (like pressuring the Justice Department and Vice President Mike Pence to do certain things) as evidence that helps illuminate Trump’s knowledge and intent for his private acts as a candidate. Dreeben says the jury needs to understand the whole “integrated conspiracy” but prosecutors would accept a jury instruction in which the judge would say they cannot impose liability for the official actions but may consider them as evidence of his knowledge and intent for the other actions. That’s how courts handle protected speech that is evidence to a larger conspiracy, he notes.

Justice Barrett picks up the question of timing again. She suggests that if prosecutors want to take Trump quickly to trial, they could simply drop those parts of the indictment that seem to be his official acts as president and proceed with only those parts of the indictment that reflect Trump’s private actions taken as a candidate for office. Dreeben is not wild about that idea.

Dreeben suggests that allegations in the “private acts bucket,” as Justice Jackson just called it, would include things like the scheme to create fake electors and the way in which Trump fomented a mob of his supporters to violently attack the Capitol on Jan. 6.

Justice Barrett seems to signal that she is less likely to find that presidents have blanket immunity for their official acts. When Dreeben says the system needs to balance the effective functioning of the presidency and accountability for a former president under the rule of law, and the existing system does that pretty well or maybe needs a few ancillary rules but that is different from the “radical proposal” put forward by Trump’s legal team, she says: “I agree.”

Dreeben, in a balancing act that seems to acknowledge that the court is looking for some form of criminal immunity for presidents, says he is trying to do two things at once, neither of them easy. He wants to design a system to find some rules that preserve the “effective functioning of the presidency” but that still allows for “accountability” if presidents violated the law.

Kavanaugh asks Dreeben about Obama’s drone strike that killed an American citizen suspected of terrorism, Anwar al-Awlaki, which Trump’s lawyer invoked in his opening. Dreeben notes that the Office of Legal Counsel analyzed the question and found that the murder statute did not apply to presidents when they were acting under public authority, so authorizing the strike was lawful. This is the way the system can function, he said — the Justice Department analyzes laws carefully and with established principles.

Justice Kavanaugh signals that he is likely to find that presidents must have immunity for their official actions. He talks about how the threat of prosecution by independent counsels (under a law that lapsed in 1999) hampered Presidents Reagan, George H.W. Bush and Clinton, and says a 1984 ruling upholding that structure as constitutional was one of the Supreme Court’s biggest mistakes. (Notably, Kavanaugh was a prosecutor on the staff of independent counsel Ken Starr during his investigation into President Bill Clinton, before becoming a White House lawyer under President George W. Bush.)

Dreeben tries to push back on Kavanaugh’s argument by saying that even after Watergate, even after all of the independent counsel investigations mentioned above, the legal system has survived without “having gone off on a runaway train” of actual criminal prosecutions against former presidents.

The Supreme Court rejected Bill Clinton’s claim of immunity.

In Clinton v. Jones in 1997, the Supreme Court unanimously allowed a sexual harassment suit against President Bill Clinton to proceed while he was in office, discounting concerns that it would distract him from his official responsibilities. Both of his appointees, Justices Ruth Bader Ginsburg and Stephen G. Breyer, voted against him.

“The president is subject to judicial process in appropriate circumstances,” Justice John Paul Stevens wrote for the court, adding, “We have never suggested that the president, or any other official, has an immunity that extends beyond the scope of any action taken in an official capacity.”

The case was in one sense harder than the one against Mr. Trump, as it involved a sitting president. In another sense, though, it was easier, as it concerned an episode said to have taken place before Mr. Clinton took office (Paula Jones, an Arkansas state employee, said Mr. Clinton had made lewd advances in a hotel room when he was governor of the state).

The case is best remembered for a prediction in Justice Stevens’s majority opinion that “it appears to us highly unlikely to occupy any substantial amount of petitioner’s time.” In fact, it led to Mr. Clinton’s impeachment.

In the same paragraph, Justice Stevens made a second prediction.

“In the more than 200-year history of the Republic, only three sitting presidents have been subjected to suits for their private actions,” he wrote. “If the past is any indicator, it seems unlikely that a deluge of such litigation will ever engulf the presidency.”

Suits against Presidents Theodore Roosevelt and Harry S. Truman were dismissed, and one against President John F. Kennedy involving a car accident during his 1960 campaign was settled. The case against Mr. Clinton added a fourth.

Justice Stevens, who died in 2019, failed to anticipate the enormous volume of civil and criminal litigation in which Mr. Trump and his businesses have been named as defendants.

We are now over the two-hour mark of the Supreme Court’s arguments in the Trump immunity case. The Justice Department lawyer has continued to face skeptical questions from many of the court’s conservatives, several of whom appear particularly focused on how to draw the line between a president’s core powers and non-core powers. In other words, what actions by a president might be shielded from prosecution and what would not. The questioning suggests that some of the justices may favor a ruling that could lead to more lower-court proceedings, perhaps delaying the trial.

The Supreme Court’s relatively new process (coming out of Covid) of letting each justice ask questions at the end in order of seniority has an interesting consequence, as seen here. Dreeben kept wanting to say these things about government legal memos and to go into the details about the actions Trump is accused of taking, but the Republican-appointed justices kept cutting him off. It’s the turn of Kagan, a Democratic appointee, to ask any final questions she wants, and she is letting him talk on and on.

Much of the discussion this morning has swirled around the question of whether, without immunity, presidents will be hounded by their rivals with malicious charges after leaving office. Alito and other conservatives on the court seem concerned that the Trump prosecutions will open the door to endless attacks against future presidents.

The other main topic of discussion has been whether presidents enjoy some form of immunity for carrying out their official duties and, if so, how those official actions are defined. That’s an important question for the Trump election case because Trump has claimed he was acting in his role as president when, by his own account, he sought to root out fraud in the 2020 vote count. It’s also important for a different reason: the justices could send the official acts question back to a lower court to sort out, and that process could take a long time, delaying the case's trial until after this year’s election.

Justice Alito suggests that there is a risk to our stable democracy if presidents who lose close elections would not be allowed to retire in peace but could face prosecution. He has essentially flipped the situation under consideration upside down: that Trump is being prosecuted for having used fraud to remain in power after losing a close election.

A part of this exchange between Justice Alito and the Justice Department's lawyer, Dreeben, gets at a pressure point in American-style democracy and the rule of law. One of the safeguards against illegitimate prosecutions of ex-presidents, Dreeben says, is that if the Justice Department has advised the president that doing something would be lawful, the department could not later turn around and prosecute the now-former president for relying on that advice and doing that thing.

Alito points out that this creates an incentive for presidents to appoint attorneys general who will just tell them that anything they want to do would be legal. Indeed — that is a critique of the Office of Legal Counsel system, in which politically appointed lawyers decide what the law means for the executive branch.

An example: During the George W. Bush administration, memos about post-9/11 surveillance and torture were written by a politically appointed lawyer with idiosyncratically broad views of a president’s supposed power, as commander in chief, to authorize violations of surveillance and torture laws. The Justice Department later withdrew those memos as espousing a false view of the law, but held that officials who had taken action based on those memos could not be charged with crimes.

Justice Alito suggests there are not enough legal safeguards in place to protect presidents against malicious prosecution if they don’t have some form of immunity. He tells Dreeben that the grand jury process isn’t much of a protection because prosecutors, as the saying goes, can indict a ham sandwich. When Dreeben tries to argue that prosecutors sometimes don’t indict people who don’t deserve it, Alito dismissively says, “Every once in a while there’s an eclipse too.”

If you are just joining in, the justices are questioning the Justice Department lawyer, Michael Dreeben, about the government’s argument that former President Trump is not absolutely immune from prosecution on charges that he plotted to subvert the 2020 election. Dreeben has faced skeptical questions from several of the conservative justices, including both Justices Alito and Kavanaugh, who have suggested that the fraud conspiracy statute being used against the former president is vague. That statute is central to the government’s case against Trump.

Justice Alito now joins Justice Kavanaugh in suggesting that the fraud conspiracy statute is very vague and broadly drawn. That is bad news for the indictment brought against Trump by Jack Smith, the special counsel.

The scope and viability of this fraud statute, which is absolutely central to the Trump indictment, wasn’t on the menu of issues seemingly at play in this hearing. Kavanaugh and Alito appear to have gone out of their way to question its use in the Trump case.

Justice Sotomayor points out that under the Trump team’s theory that a criminal statute has to clearly state that it applies to the presidency for it to cover a president’s official actions, there would essentially be no accountability at all. Because only a tiny handful of laws mention the president, that means a president could act contrary to them without violating them. As a result, the Senate could not even impeach a president for violating criminal statutes, she says — because he would not be violating those laws if they don’t apply to the president.

Dreeben is under heavy fire from the court’s conservatives.

The precedent most helpful to Trump: Nixon v. Fitzgerald.

In 1982, in Nixon v. Fitzgerald , the Supreme Court ruled that former President Richard M. Nixon had absolute immunity from civil lawsuits — ones brought by private litigants seeking money — for conduct “within the ‘outer perimeter’ of his official responsibility.”

The ruling is helpful to former President Donald J. Trump, establishing as it does that immunity can be expansive, lives on after a president leaves office and extends to the very limits of what may be said to be official conduct.

But the decision also falls well short of dictating the outcome in the case that is being argued on Thursday, which concerns a criminal prosecution, not a civil suit.

The 1982 case arose from a lawsuit brought by an Air Force analyst, A. Ernest Fitzgerald, who said he was fired in 1970 in retaliation for his criticism of cost overruns. By the time the Supreme Court acted, Nixon had been out of office for several years.

“In view of the special nature of the president’s constitutional office and functions,” Justice Lewis F. Powell Jr. wrote for the majority 5-to-4 decision, “we think it appropriate to recognize absolute presidential immunity from damages liability” for Nixon’s official conduct, broadly defined.

But the decision drew a sharp line between civil suits, which it said can be abusive and harassing, and criminal prosecutions like the one Mr. Trump is facing.

“In view of the visibility of his office and the effect of his actions on countless people, the president would be an easily identifiable target for suits for civil damages,” Justice Powell wrote, adding, “The court has recognized before that there is a lesser public interest in actions for civil damages than, for example, in criminal prosecutions.”

Chief Justice Warren E. Burger underscored the point in a concurring opinion. “The immunity is limited to civil damages claims,” he wrote.

Even in the context of civil suits, Nixon v. Fitzgerald conferred immunity only on conduct within the “outer perimeter” of a president’s official duties. Jack Smith, the special counsel, has said that Mr. Trump’s efforts to subvert democracy are well outside that line.

The Justice Department has already granted sitting presidents immunity while they are in office.

Former President Donald J. Trump’s claim that former presidents must enjoy “complete immunity” from prosecution for any crimes they committed in office would significantly expand the temporary immunity that sitting presidents already have.

Nothing in the Constitution or federal statutes says that presidents are shielded from being prosecuted while in office, and no court has ever ruled that way. But political appointees in the Justice Department’s Office of Legal Counsel, whose interpretations are binding on the executive branch, have declared that the Constitution implicitly establishes such immunity.

This argument boils down to practicalities of governance: The stigma of being indicted and the burden of a trial would unduly interfere with a president’s ability to carry out his duties, Robert G. Dixon Jr. , then the head of the Justice Department’s Office of Legal Counsel, wrote in a memo in September 1973 . This would prevent the executive branch “from accomplishing its constitutional functions” in a way that cannot “be justified by an overriding need,” he added.

Mr. Dixon, an appointee of President Richard M. Nixon, wrote his memo against the backdrop of the Watergate scandal, when Mr. Nixon faced a criminal investigation by a special counsel, Archibald Cox. The next month, Nixon’s solicitor general, Robert H. Bork , in a court brief , similarly argued for an “inference” that the Constitution makes sitting presidents immune from indictment and trial.

(That same month, Mr. Nixon had Mr. Cox fired in the so-called Saturday Night Massacre. Mr. Nixon’s attorney general and deputy attorney general resigned rather than carry out his orders to oust the prosecutor; Mr. Nixon then turned to Mr. Bork, the department’s No. 3, who proved willing to do it. Amid a political backlash, Mr. Nixon was forced to allow a new special counsel, Leon Jaworski , to resume the investigation.)

The question arose again a generation later, when President Bill Clinton faced an investigation by Kenneth Starr, an independent counsel, into the Whitewater land deal that morphed into an inquiry into his affair with Monica Lewinsky, a White House intern. Randolph D. Moss , Mr. Clinton’s appointee to lead the Office of Legal Counsel, reviewed the Justice Department’s 1973 opinions and reaffirmed their conclusions .

Legal scholars, as well as staff for prosecutors investigating presidents, have disputed the legitimacy of that constitutional theory. In 1974, Mr. Jaworski received a memo from his staff saying he could, in fact, indict Mr. Nixon while he was in office, and he later made that case in a court brief .

And in a 56-page memo in 1998, Ronald Rotunda, a prominent conservative constitutional scholar whom Mr. Starr hired as a consultant on his legal team, rejected the view that presidents are immune from prosecution while in office. Mr. Starr later said that he had concluded that he could indict Mr. Clinton.

“It is proper, constitutional, and legal for a federal grand jury to indict a sitting president for serious criminal acts that are not part of, and are contrary to, the president’s official duties,” Mr. Rotunda wrote. “In this country, no one, even President Clinton, is above the law.”

Mr. Starr commissioned the Rotunda memo as he was drafting a potential indictment of Mr. Clinton, and Mr. Starr decided that he could charge the president while in office. In the end, however, both Mr. Jaworski and Mr. Starr decided to let congressional impeachment proceedings play out and did not try to bring indictments while Mr. Nixon and Mr. Clinton remained in office.

The question may never be definitively tested in the courts. In 1999, Congress allowed a law that created independent counsels like Mr. Starr — prosecutors who do not report to the attorney general — to expire, and the Justice Department issued regulations to allow for the appointment of semiautonomous special counsels for inquiries into potential high-level wrongdoing in the executive branch.

Special counsels are, however, bound by Justice Departments policies and practices — including the Office of Legal Counsel’s proclamation that sitting presidents are temporarily immune from criminal indictment or trial.

Alan Feuer and Charlie Savage

Is there such a thing as executive immunity?

There are no direct precedents on the broad question of whether presidents have criminal immunity for their official actions.

The Supreme Court has held that presidents are absolutely immune from civil lawsuits related to their official acts , in part to protect them against ceaseless harassment and judicial scrutiny of their day-to-day decisions. The court has also held that presidents can be sued over their personal actions .

The Supreme Court has further found that while presidents are sometimes immune from judicial subpoenas requesting internal executive branch information, that privilege is not absolute. Even presidents, the court has decided, can be forced to obey a subpoena in a criminal case if the need for information is great enough.

But until Mr. Trump wound up in court, the Supreme Court has never had a reason to decide whether former presidents are protected from being prosecuted for official actions. The Justice Department has long maintained that sitting presidents are temporarily immune from prosecution because criminal charges would distract them from their constitutional functions. But since Mr. Trump is not in office, that is not an issue.

The closest the country has come to the prosecution of a former president over official actions came in 1974, when Richard M. Nixon resigned to avoid being impeached over the Watergate scandal. But a pardon by his successor, President Gerald R. Ford, protected Nixon from indictment by the Watergate special prosecutor.

Mr. Smith’s team has argued that Ford’s pardon — and Nixon’s acceptance of it — demonstrates that both men understood that Nixon was not already immune. Mr. Trump’s team has sought to counter that point by arguing — inaccurately — that Nixon faced potential criminal charges only over private actions, like tax fraud. But the special prosecutor weighed charging Nixon with abusing his office to obstruct justice.

Mr. Trump’s team has argued that denying his claims risks unleashing a routine practice of prosecuting former presidents for partisan reasons. But Mr. Smith’s team has argued that if courts endorse Mr. Trump’s theory, then future presidents who are confident of surviving impeachment could, with impunity, commit any number of crimes in connection with their official actions.

“Such a result would severely undermine the compelling public interest in the rule of law and criminal accountability,” prosecutors wrote.

Hypothetical questions test the limits of Trump’s immunity claim.

An exchange during an appeals court argument in January about a hypothetical political assassination tested former President Donald J. Trump’s claim that he is absolutely immune from prosecution for his official conduct.

His lawyer, D. John Sauer, has urged the justices to consider only what he is actually accused of: plotting to subvert the 2020 election. But hypothetical questions are routine at the Supreme Court, and they have a way of illuminating the contours and implications of legal theories.

That is what happened in January, when Judge Florence Y. Pan of the U.S. Court of Appeals for the District of Columbia had to press Mr. Sauer to get an answer to a hypothetical question: Are former presidents absolutely immune from prosecution, even for murders they ordered while in office?

“I asked you a yes-or-no question,” Judge Pan said. “Could a president who ordered SEAL Team 6 to assassinate a political rival, who was not impeached, would he be subject to criminal prosecution?”

Mr. Sauer said his answer was a “qualified yes,” by which he meant no. He explained that prosecution would be permitted only if the president were first impeached by the House and convicted by the Senate.

Impeachments of presidents are rare: There have been four in the history of the Republic, two of them of Mr. Trump. The number of convictions, which require a two-thirds majority of the Senate: zero.

Mr. Sauer’s statement called to mind a 2019 federal appeals court argument over whether Mr. Trump could block state prosecutors from obtaining his tax and business records. He maintained that he was immune not only from prosecution but also from criminal investigation so long as he was president.

At that time, Judge Denny Chin of the Second Circuit pressed William S. Consovoy, a lawyer for Mr. Trump, asking about his client’s famous statement that he could shoot someone on Fifth Avenue without losing political support.

“Local authorities couldn’t investigate?” Judge Chin asked, adding: “Nothing could be done? That’s your position?”

“That is correct,” said Mr. Consovoy. “That is correct.”

This headline followed: “If Trump Shoots Someone on 5th Ave., Does He Have Immunity? His Lawyer Says Yes.”

For his part, Mr. Sauer does not seem eager to revisit the question about assassinations. Indeed, in asking the Supreme Court to hear Mr. Trump’s appeal, Mr. Sauer urged the justices not to be distracted by “lurid hypotheticals” that “almost certainly never will occur.”

What counts as an official act as president?

Another issue that has come up in lower courts in this case was what counted as an official act for a president, as opposed to a private action that was not connected to his constitutional responsibilities.

If the justices want to dispose of the dispute without definitively ruling on whether presidents are immune from prosecution for official acts, they could do so by finding that the specific steps former President Donald J. Trump took to remain in office that are cited in the federal indictment were not official actions. If so, the broader immunity question would not matter, and the prosecution could proceed.

The acts by Mr. Trump cited in the indictment include using deceit to organize fake slates of electors and to try to get state officials to subvert legitimate election results; trying to get the Justice Department and Vice President Mike Pence to help fraudulently alter the results; directing his supporters to the Capitol on Jan. 6, 2021; and exploiting the violence and chaos of their ensuing riot.

In its court filings, Mr. Trump’s team has sought to reframe those accusations not only as official actions, but innocuous or even admirable ones.

“All five types of conduct alleged in the indictment constitute official acts,” they wrote. “They all reflect President Trump’s efforts and duties, squarely as chief executive of the United States, to advocate for and defend the integrity of the federal election, in accord with his view that it was tainted by fraud and irregularity.”

Mr. Smith’s team has argued that they should be seen as the efforts of a person seeking office, not of an officeholder carrying out government responsibilities.

“Those alleged acts were carried out by and on behalf of the defendant in his capacity as a candidate, and the extensive involvement of private attorneys and campaign staff in procuring the fraudulent slates as alleged in the indictment underscores that those activities were not within the outer perimeter of the office of the presidency,” they wrote.

Judge Tanya S. Chutkan, who is overseeing Mr. Trump’s case in Federal District Court in Washington, issued her ruling rejecting Mr. Trump’s immunity claim without including any detailed analysis of whether his acts were “official.”

If the Supreme Court were to send the matter back to her to take a stab at answering that question before restarting the appeals process, Mr. Trump will, at a minimum, have used up additional valuable time that could help push any trial past the election.

Noah Weiland and Alan Feuer

Here are the lawyers arguing before the Supreme Court.

The two lawyers arguing before the Supreme Court on Thursday have each played a role in some of the defining legal battles stemming from Mr. Trump’s term in office.

Arguing the case for the special counsel Jack Smith will be Michael Dreeben, who worked for a different special counsel’s office that scrutinized Mr. Trump’s presidency: Robert S. Mueller III’s investigation into links between Russia and associates of Mr. Trump. Mr. Dreeben, one of the nation’s leading criminal law experts, has made more than 100 oral arguments before the Supreme Court, including when he served as deputy solicitor general.

On Mr. Mueller’s team, he handled pretrial litigation, defending the scope of the investigation and preventing the office from losing cases on appeal. He also helped with a second part of Mr. Mueller’s investigation, examining whether Mr. Trump had tried to obstruct the inquiry in his dealings with associates involved in the case.

Mr. Dreeben, who was heavily involved in the writing of Mr. Mueller’s final report on his investigation, supported an interpretation of presidential power that emphasized limits on what a president could do while exercising his or her powers, according to “Where Law Ends,” a book written by Andrew Weissmann, another prosecutor on Mr. Mueller’s team.

After Mr. Mueller’s investigation concluded, Mr. Dreeben took a teaching position at Georgetown University’s law school and returned to private practice at O’Melveny, arguing in front of the Supreme Court on behalf of the city of Austin over a First Amendment dispute about the placement of digital billboards.

Opposing Mr. Dreeben in front of the Supreme Court will be D. John Sauer, a lawyer based in St. Louis who once served as the solicitor general of Missouri. Mr. Sauer joined Mr. Trump’s legal team late last year to handle appellate matters, including his challenge to a gag order imposed on him in the election case in Washington.

As Missouri’s solicitor general, Mr. Sauer took part in a last-ditch effort to keep Mr. Trump in power after his defeat in the 2020 election, filing a motion on behalf of his state and five others in support of an attempt by Texas to have the Supreme Court toss out the results of the vote count in several key swing states.

He also joined in an unsuccessful bid with Texas in asking the Supreme Court to stop the Biden administration from rescinding a Trump-era immigration program that forces certain asylum seekers arriving at the southwestern border to await approval in Mexico.

When he left the solicitor general’s office last January, Mr. Sauer, who once clerked for Justice Antonin Scalia, returned to his private firm, the James Otis Law Group. The firm is named after a prominent Revolutionary War-era lawyer who built a career out of challenging abuses by British colonial forces.

To justify his defense in the immunity case, Trump turns to a familiar tactic.

When the Supreme Court considers Donald J. Trump’s sweeping claims of executive immunity on Thursday, it will break new legal ground, mulling for the first time the question of whether a former president can avoid being prosecuted for things he did in office.

But in coming up with the argument, Mr. Trump used a tactic on which he has often leaned in his life as a businessman and politician: He flipped the facts on their head in an effort to create a different reality.

At the core of his immunity defense is a claim that seeks to upend the story told by federal prosecutors in an indictment charging him with plotting to overturn the 2020 election. In that indictment, prosecutors described a criminal conspiracy by Mr. Trump to subvert the election results and stay in power.

In Mr. Trump’s telling, however, those same events are official acts that he undertook as president to safeguard the integrity of the race and cannot be subject to prosecution.

In many ways, Mr. Trump’s immunity claim is breathtaking. In one instance, his lawyers went so far as to say that a president could not be prosecuted even for using the military to assassinate a rival unless he was first impeached.

But the wholesale rewriting of the government’s accusations — which first appeared six months ago in Mr. Trump’s motion to dismiss the election interference case — may be the most audacious part of his defense. It was certainly a requisite step his lawyers had to take to advance the immunity argument.

Other courts have ruled that presidents enjoy limited immunity from civil lawsuits for things they did as part of the formal responsibilities of their job. To extend that legal concept to criminal charges, Mr. Trump’s lawyers needed to reframe all of the allegations lodged against him in the election interference case as official acts of his presidency rather than as the actions of a candidate misusing his power.