Introduction

To say that the legal principle actus non facit reum nisi mens sit rea¹ is long-standing would be a considerable understatement. According to some legal scholars, the phrase, which means "the act is not culpable unless the mind is guilty," has been in use for "at least approximately one thousand years."² Embodied in the phrase is the "universal and persistent" notion that "an injury can amount to a crime only when inflicted by intention."³ In contemporary American law, the concept of mens rea, or a "guilty mind," reflects this idea that a crime generally must consist of not only a "harmful act" but also a "mental element" or criminal intent sufficient to justify punishment.⁴

A world of complexity belies the seeming simplicity of the principle that a crime requires a guilty mind. To start, "mental element," "guilty mind," or "state of mind"⁵ are somewhat imprecise terms, as they may be used to refer to "matters that are not really mental at all" (for instance, crimes that only require a mens rea of negligence).⁶ Additionally, courts face persistent issues in interpreting mens rea standards like "knowledge," "willfulness," and "intent" and determining which elements in particular crimes must meet these standards.⁷

Moreover, though courts have pronounced in sweeping language the paramount importance of imposing criminal punishment only on those who are mentally culpable, a class of so-called "regulatory" or "public welfare" offenses are said to be "strict liability" crimes in that they require no mens rea for their commission at all.⁸

One resource that has played a significant role in the development and clarification of certain mens rea principles is the Model Penal Code (MPC).⁹ The MPC is a major work of legal scholarship first produced in 1962 that was intended to establish a comprehensive model statute that American jurisdictions could use to revise their criminal codes.¹⁰ Many states have, in whole or part, supplanted "confused, vague, and inconsistent" approaches to mental states drawn from the common law with the more systematic approach to state-of-mind requirements found in the MPC's "culpability" provisions.¹¹ Federal courts also have looked to MPC principles for guidance in interpreting federal law,¹² notwithstanding the fact that federal criminal statutory law (largely codified at Title 18) contains no uniform mens rea standards or generally applicable definitions of mental-state terms.¹³ Given that federal statutory law lacks such consistent rules for assessing and applying mens rea terms and requirements across criminal statutes, courts have had to use canons of statutory interpretation¹⁴ and adopt certain mens rea-specific presumptions when the state of mind required for a particular federal offense is unclear.¹⁵

In light of the ad hoc nature of state-of-mind requirements under federal law, Congress has shown interest for decades in establishing more systematized mens rea standards and application rules.¹⁶ Because the issue is one of perennial interest to Congress, this report provides an overview of mens rea requirements for federal crimes.¹⁷ The report first sketches the common-law background of the concept of mens rea, summarizes the MPC's innovations on the subject, and then explores mens rea standards and interpretive issues in federal statutes and caselaw.¹⁸ The report concludes with a brief discussion of recent proposals that would impact federal mens rea requirements and some of the arguments in favor of and in opposition to such proposals.

Background

A crime traditionally has been understood to consist of the concurrence of both a proscribed act (the actus reus) and a "guilty mind" (or mens rea).¹⁹ The concept of a mental element—mens rea, scienter, state of mind, criminal intent, or an equivalent term—being necessary for a prohibited act to be sufficiently blameworthy to justify criminal punishment has endured for hundreds of years, if not longer.²⁰ In its early form at English common law, at least according to some scholars, mens rea embodied the notion of an intent to do an act with an "evil motive."²¹ This "original notion . . . was gradually transformed by a centuries-long process that attempted to identify specific states of mind required for the commission of particular offenses."²² The concept of a guilty mind as a necessary component of crime "took deep and early root in American soil,"²³ but by the middle of the twentieth century, the common-law development of particular state-of-mind requirements on a crime-by-crime basis (and their inconsistent codification, in whole or in part, in state criminal codes) led to considerable disarray and confusion.²⁴

This confusion is perhaps best reflected in the development of the concepts of "general intent" and "specific intent" as a shorthand way to describe the mens rea classifications of common-law crimes. At a high level, many such offenses—for example, murder, battery, and larceny—can be characterized as either "specific intent" or "general intent" crimes.²⁵ In one formulation, "specific intent" denotes an intent to "achieve some additional consequence" or "commit some further act" beyond the "commission of the proscribed act."²⁶ For example, larceny likely would be considered a specific intent crime, as it often requires obtaining control over the property of another (the proscribed act) with the intent "to deprive the owner of the stolen property permanently."²⁷ By contrast, in the words of one federal appellate court, "a general intent crime requires only that the act was volitional (as opposed to accidental), and the defendant's state of mind is not otherwise relevant."²⁸ For instance, battery at common law "consisted of the unlawful application of force to the person of another, including an offensive touching."²⁹ This crime would be considered a general intent crime, because it does not "require any specific intent either to injure or to touch offensively, but rather only a more general intent to commit the unlawful act" of applying force.³⁰

Though the examples of larceny and battery might suggest relative clarity, delineation between "specific intent" and "general intent" crimes in fact can be problematic in several respects. For one thing, disagreement has abounded over time as to the proper meaning and usage of the two terms. As explained by the Supreme Court:

Sometimes "general intent" is used in the same way as "criminal intent" to mean the general notion of mens rea, while "specific intent" is taken to mean the mental state required for a particular crime. Or, "general intent" may be used to encompass all forms of the mental state requirement, while "specific intent" is limited to the one mental state of intent. Another possibility is that "general intent" will be used to characterize an intent to do something on an undetermined occasion, and "specific intent" to denote an intent to do that thing at a particular time and place.³¹

Additionally, even classifying a crime as requiring either specific or general intent might not necessarily serve to elucidate the requisite mental state in a meaningful way. As one scholar has framed it, the concepts of general and specific intent do not themselves "describe culpable mental states" but merely "describe the relationship between an offense's mental elements and its physical elements."³² A crime might be considered a "general intent" crime, in other words, because it does not require a specific mental state with respect to some consequence or result beyond the proscribed act (as in the battery example), but this does little to clarify the meaning of the mens rea requirement that the crime does have. Though the definition of "general intent" given above distinguishes only between volition and accident, the concept of intentionality has long been "slice[d] . . . more finely than accident versus non-accident."³³ In fact, a crime might incorporate the notion of a volitional act that brings about an unintended (read: accidental) result where the actor is highly careless in failing to appreciate the risk that a reasonable person would appreciate.³⁴ This kind of crime does not fit comfortably in either the general or the specific intent bucket, nor does a crime that requires conscious disregard of a known risk.³⁵

Exacerbating these definitional problems at common law was the proliferation of different mens rea terms that often provided little clarity as to what sort of mental state was actually required. "Terms such as willfully, corruptly, maliciously, feloniously, wrongfully, unlawfully, wantonly, intentionally, purposely, with criminal negligence, and culpably" were all used (among others), sometimes "to describe what was probably the same mental state," sometimes to describe different mental states, and often without "any further definition."³⁶ The result was "seemingly infinite shades of meaning along [a] continuum upon which" the concepts of specific and general intent resided.³⁷ It was in the context of this "variety, disparity, and confusion of [judicial] definitions of the requisite but elusive mental element"³⁸ that the drafters of the MPC sought to establish "relatively clear definitions of mental requirements and relatively straightforward rules regarding how to read these requirements into criminal statutes"³⁹ through what it termed general "culpability" rules.⁴⁰ Because the MPC approach has had a significant impact on the development and understanding of the mental element of crime in general,⁴¹ this report provides a brief overview of the MPC's culpability provisions.

Model Penal Code Approach

As noted above, the MPC was intended to be used as a model for criminal code reform across jurisdictions.⁴² It has proved to be extremely influential, with many states revising their codes in light of the MPC's principles and with some federal courts looking to those principles in construing federal law.⁴³

The MPC's culpability provisions are found in Article 2 of Part I, principally Section 2.02 and surrounding sections. One of these provisions' core achievements is in "reduc[ing] nearly eighty miscellaneous culpability terms to five carefully defined levels."⁴⁴ These levels have become a prevalent, if not the predominant, prism through which courts view state-of-mind distinctions.⁴⁵ The five levels of culpability are: (1) purpose; (2) knowledge; (3) recklessness; (4) negligence; and (5) strict liability.⁴⁶ The MPC also clarifies the relationship between these different culpability levels and the offense elements to which they apply by dividing elements into three categories: (1) conduct, (2) attendant circumstances, and (3) results.⁴⁷ The element categories are not defined, but an example of conduct and circumstance elements might involve a crime of having sexual intercourse with a minor, with intercourse being the conduct element and the age of the victim being the circumstance element.⁴⁸ An example of a result element would be engaging in conduct that causes the death of another human being, with death being the proscribed result.⁴⁹

Each culpability level in the MPC is defined in relation to each kind of objective offense element.⁵⁰ The table below reflects the definitions of the MPC's culpability levels for the three element categories:

As the table reflects, the MPC's culpability levels may be viewed in a kind of descending order of intentionality. "Purposely" generally requires an element to be the actor's "conscious object," "knowingly" requires the actor's awareness to a practical certainty or of a high probability (regardless of what the actor desires or has as their object), "recklessly" requires the actor's awareness of a substantial risk, and "negligence" requires no awareness at all but merely that the actor objectively should have been aware of a substantial risk. For a limited category of strict liability offenses, the mental state of the actor is irrelevant.⁵⁶ These definitions represent an effort to cut through the confusing morass of mens rea terms that had existed up to that point.⁵⁷ The categorization of offense elements and the implicit recognition that the requisite mens rea might be different and should be analyzed separately with respect to each offense element also reflects a shift away from a prior notion that "each offense has one state of mind requirement," i.e., that criminal offenses may be classified simply as "general intent" or "specific intent" rather than specifying what state of mind is actually required for which components of the crime.⁵⁸

Beyond the definitions of mental-state requirements and the move towards mens rea element analysis with respect to those requirements, the MPC establishes certain general principles of interpretation that apply in assessing the mental state or states required for a particular offense.⁵⁹ Most notably, the MPC creates a baseline culpability standard for any material element⁶⁰ that does not explicitly contain one—Section 2.02(3) states that unless otherwise provided, "[w]hen the culpability sufficient to establish a material element of an offense is not prescribed by law," the element is established if the person acts at least recklessly.⁶¹ Coupled with this default rule is a rule that if an offense prescribes the culpability level sufficient for commission of the offense without specifying which elements of the offense carry that specific culpability requirement, the requirement applies to all material elements "unless a contrary purpose plainly appears."⁶² For example, for an offense of knowingly killing a "house pigeon," the prosecution would have to prove that the actor knowingly killed and that he knew what he killed was a house pigeon, unless the text of the law in question "plainly" reflected that knowledge of the type of pigeon should not be required.⁶³

The MPC additionally provides a number of rules on other points of law that may relate to mental-state requirements, such as the mens rea for inchoate crimes and certain defenses.⁶⁴ This report addresses the MPC approach to these topics as a point of comparison with approaches under federal law in subsequent sections.⁶⁵

In the decades since the MPC's initial development, a substantial body of legal scholarship has offered critiques of, and potential refinements to, its culpability provisions.⁶⁶ For instance, some commentators have taken issue with the "narrow distinction" between knowledge and recklessness with respect to a circumstance, which appears to turn on the murky question of what is highly probable versus a "substantial risk."⁶⁷ Others have noted the conflict and inconsistency that can arise in applying the rule that recklessness is the default when culpability is undefined over the rule that a culpability requirement attached to one material element normally attaches to all.⁶⁸ Nonetheless, legal scholars appear largely to prefer the MPC's approach to mental states over the disarray of the common law, asserting that the MPC's culpability provisions are a "tremendous advance."⁶⁹ Many U.S. jurisdictions also have either adopted a number of the provisions or been influenced by them,⁷⁰ and the Supreme Court has also looked to the MPC as a "source of guidance" in construing mens rea requirements in federal criminal statutes.⁷¹ What is notable about federal law, however, is that the MPC's culpability provisions have not been codified or adopted on a broad scale. Instead, federal law largely embodies an ad hoc approach, which this report now examines in more detail.

Federal Mens Rea Requirements

In 1966, Congress created the National Commission on Reform of Federal Criminal Laws, which was given a broad mandate to "review and study . . . the statutory and case law of the United States . . . for the purpose of formulating and recommending to the Congress legislation which would improve the federal system of criminal justice."⁷² In its working papers, the Commission painted a rather unflattering picture of the state of mens rea requirements for federal crimes.⁷³ The Commission noted that in contrast with the MPC, federal statutory law did not contain uniform and defined mental-state standards or rules of construction for the application of mens rea terms.⁷⁴ Instead, according to the Commission, federal criminal statutes drew from common-law terminology in articulating mental-state requirements (if at all) on an ad hoc, statute-by-statute basis.⁷⁵ The Commission identified, in Title 18 of the U.S. Code alone, 78 different mens rea terms.⁷⁶ According to the Commission, this "staggering array" of mental-state terms did not "reflect accurately or consistently what are the mental elements of the various crimes," nor was there any "discernible pattern or consistent rationale" for why particular terms were used in particular statutes.⁷⁷ As such, the Commission acknowledged that courts were left to discern what Congress meant by including (or not including) one of the plethora of terms in any given context, which led to the same terms having different, and sometimes inconsistent, meanings depending on the statute.⁷⁸

The Commission's final report and recommendations, submitted to Congress and the President in 1971, proposed, among other things, to remedy the confusion over federal mens rea requirements by establishing generally applicable culpability rules and definitions similar to those found in the MPC.⁷⁹ Legislation introduced based on the Commission's report gained some traction but did not become law.⁸⁰ More recent legislation aimed at altering federal mens rea standards has also been introduced but has not become law;⁸¹ as such, it remains that the U.S. Code has no general mens rea term definitions or interpretive rules, and dozens of different terms are used throughout the Code.⁸² Courts construe these terms "depending on the circumstances of the case and a reading of congressional intent," with the result that identical mens rea terms "vary significantly" from statute to statute.⁸³ In other words, ascertaining the mens rea required for a federal crime will often necessitate reference to judicial decisions construing the language used to define that particular offense.

For the foregoing reasons, and given that at least one estimate puts the number of federal statutes carrying criminal penalties in the thousands,⁸⁴ it would be unwieldy to examine comprehensively federal mens rea requirements in a systematic way. Instead, this section of the report (1) examines more broadly the interpretive approaches and presumptions that the Supreme Court and other federal courts have utilized to glean congressional intent in construing the mental-state requirements (if any) of federal criminal statutes; (2) provides a survey of mental-state requirements under federal law, loosely grouped along the lines of the MPC's culpability categorizations; and (3) addresses certain additional aspects of federal criminal liability that implicate mens rea—specifically, inchoate offenses of attempt and conspiracy, corporate criminal liability, and defenses.

Federal Mens Rea Interpretive Approach

The Supreme Court has "long recognized that determining the mental state required for commission of a federal crime requires construction of the statute and inference of the intent of Congress."⁸⁵ Three questions routinely arise with respect to determining the requisite mental state for a particular federal crime: (1) whether the statute establishing the crime contains a mental-state requirement or requirements; (2) if the statute contains mental-state requirements, which elements of the offense must meet which requirements; and (3) what the mental-state requirements mean.⁸⁶ Because statutory language is not always clear, the federal courts have "developed a rich—if somewhat untidy—body of substantive background principles" and presumptions that guide the interpretive exercise.⁸⁷ This section and the next address each of the three questions identified above and the relevant principles and presumptions that courts may apply to help answer those questions.

Whether Mens Rea is Required

Because the language of a statute is the starting point in statutory construction,⁸⁸ a federal criminal statute containing a mens rea term such as "knowingly" clearly indicates that Congress meant to require some culpable mental state.⁸⁹ When Congress omits an express mens rea requirement from the statutory text, however, the question arises as to whether that omission was intentional—in other words, whether Congress intended to dispense with any mental-state requirement and make the offense one of strict liability.⁹⁰ In a series of cases, the Supreme Court has recognized, at least with respect to federal offenses based on traditional common-law crimes, a "presumption in favor of scienter,"⁹¹ meaning the Court will ordinarily presume a "degree of knowledge sufficient to make a person legally responsible for the consequences of his or her act or omission."⁹² Put differently, the Court has held that ordinarily "some indication of congressional intent, express or implied, is required to dispense with mens rea as an element of a crime,"⁹³ and mere omission of a mens rea term will not be considered a sufficient indication of such intent.⁹⁴

The genesis of the presumption in favor of scienter can be traced to the Supreme Court's 1952 decision in Morissette v. United States.⁹⁵ In Morissette, the Court, in reading an intent requirement into a statute proscribing theft or conversion of federal property,⁹⁶ spoke broadly of intent as "so inherent in the idea of" crimes codified from common law "that it required no statutory affirmation" and counseled "caution in assuming that Congress, without clear expression," sought to eliminate any mental-state requirement.⁹⁷ A later Supreme Court decision more clearly articulated a presumption that Congress "legislated against the background of . . . traditional legal concepts which render intent a critical factor"⁹⁸ and further acknowledged such a presumption as consistent with a separate interpretive doctrine that "ambiguity concerning the ambit of criminal statutes should be resolved in favor of lenity."⁹⁹

Assuming the presumption of mens rea applies, and thus that a mental-state requirement should be read into a statute that does not explicitly contain one, the question becomes what kind of mental state is required. In this respect, the Supreme Court has held that "[t]he presumption in favor of scienter requires a court to read into a statute only that mens rea which is necessary to separate wrongful conduct from 'otherwise innocent conduct.'"¹⁰⁰ Typically, the standard of knowledge is sufficient to meet this requirement.¹⁰¹ For instance, in Staples v. United States, the Court held that a statute making it unlawful to receive or possess certain kinds of unregistered firearms¹⁰² required knowledge of the features of the firearm that brought it within the scope of the statute.¹⁰³ In reaching its conclusion, the Court noted that omitting a requirement that a "defendant know the facts that make his conduct illegal" would "impose criminal sanctions on a class of persons whose mental state . . . makes their actions entirely innocent."¹⁰⁴

The Court also has recognized a class of "'public welfare' or 'regulatory' offenses" to which the presumption will not apply (i.e., offenses where statutory silence is treated as imposing "a form of strict criminal liability" by "not requir[ing] the defendant to know the facts that make his conduct illegal.")¹⁰⁵ Typically, "such offenses involve statutes that regulate potentially harmful or injurious items" or activities, which put individuals on notice of the likelihood of regulation, ¹⁰⁶ and impose relatively small penalties.¹⁰⁷ One of the earliest examples of the Supreme Court's recognition of a public welfare offense lacking a mens rea requirement is United States v. Balint, in which the Court addressed a statute prohibiting the sale of certain narcotics without a tax form issued by the federal government.¹⁰⁸ The defendants argued that the government was required to prove that they knew the drugs they sold —derivatives of opium and coca leaves—were covered by the statute, but the Court concluded that the statute did not require proof of such knowledge.¹⁰⁹ In so doing, the Court recognized a class of "regulatory measures" lacking a scienter requirement where the emphasis was "upon achievement of some social betterment rather than . . . punishment."¹¹⁰ Acknowledging the question as one of congressional intent, the Court determined that the statute at issue fell into this class given its "manifest purpose . . . to require every person dealing in drugs to ascertain at his peril whether that which he sells comes within the inhibition of the statute," noting that the opportunity of the seller to determine the nature of the drug being sold and the difficulty of proving knowledge "[d]oubtless . . . contributed to [Congress's] conclusion" that such knowledge should not be required.¹¹¹

Subsequent cases have appeared to back away from the somewhat broad conception of strict-liability crimes presented in Balint, emphasizing the "limited circumstances" in which they will be recognized.¹¹² Ultimately, several factors may be relevant to a court's determination of whether a particular criminal statute imposes strict liability, including the nature of the statute and the particular activity or item regulated, the purpose of the criminal prohibition (i.e., punishment of wrongdoing versus protection of the public), the degree to which a defendant will be in a position to ascertain the relevant facts, and the severity of the penalties.¹¹³

In short, though the line between a public welfare offense and a traditional offense to which the presumption of mens rea applies "can be difficult to draw,"¹¹⁴ a court will generally look to "the nature of the statute and the particular character of the items regulated to determine whether congressional silence concerning the mental element of the offense should be interpreted as dispensing with conventional mens rea requirements."¹¹⁵ Strictly speaking, however, even so-called "strict liability" public welfare offenses are not viewed as completely dispensing with any state-of-mind requirement—rather, they require "only so much knowledge as is necessary to provide defendants with reasonable notification that their actions are subject to strict regulation."¹¹⁶ Put differently, public welfare offenses "require at least that the defendant know that he is dealing with some dangerous or deleterious substance" but not necessarily "the facts that make his conduct fit the definition of the offense."¹¹⁷

The absence of a mens rea requirement in a criminal statute may present constitutional difficulties in particular contexts. For instance, the Supreme Court in United States v. X-Citement Video, Inc. interpreted a statute criminalizing distribution of sexually explicit visual depictions of minors¹¹⁸ as requiring a defendant to have knowledge of the minority of those involved, in part based on First Amendment concerns.¹¹⁹ Ordinarily, restrictions on speech based on its content are presumptively unconstitutional,¹²⁰ and although child pornography generally falls within an exception for unprotected speech,¹²¹ the X-Citement Video Court recognized prior precedent as suggesting that the absence of a mens rea requirement as to the character of such materials could "raise serious constitutional doubts" under the First Amendment.¹²² Additionally, some lower courts have suggested that "the imposition of severe penalties, especially a felony conviction," for a strict-liability crime may violate the Due Process Clause of the Fifth Amendment,¹²³ as "a person acting with a completely innocent state of mind could be subjected to a severe penalty and grave damage to his reputation."¹²⁴ Nevertheless, although the Supreme Court has struck down one strict-liability city ordinance on due-process grounds in a fairly unique circumstance involving "wholly passive" conduct with no notice or opportunity to comply,¹²⁵ it has at other times appeared to affirm the constitutionality of strict-liability crimes more generally.¹²⁶ Further, at least one federal appellate court has rejected the proposition that strict-liability felonies are per se unconstitutional.¹²⁷ As such, the precise constitutional limits of strict-liability public welfare offenses are unclear.¹²⁸

Application of Mens Rea to Specific Elements

Assuming either that Congress has provided a mens rea requirement in a federal criminal statute, or that a court concludes a statute silent on the issue carries one, the question may arise as to which elements of the crime must meet that requirement. One innovation of the Model Penal Code was its recognition that the mental state for a particular crime should be analyzed on an element-by-element basis.¹²⁹ This approach is also generally employed under federal law.¹³⁰ In some statutes, Congress may have provided relatively clear instruction as to what mens rea term must be established for distinct components of the crime at issue—for example, 18 U.S.C. § 1591 makes it a crime to "knowingly" recruit a person "knowing" or "in reckless disregard of the fact" that force or other proscribed means will be used to cause the person to engage in a commercial sex act, or that the person is under the age of 18 and will be caused to engage in a commercial sex act.¹³¹ It is often the case, however, that Congress will provide penalties for a "willful" or "knowing" violation of a statute that contains multiple elements, for instance, or will omit a textual mental-state requirement for a crime that is presumed to have at least one as described above.¹³² In this circumstance, courts are left to glean congressional intent as to which elements must meet the mens rea term that either is specified or presumed.

As with the question of whether a statute has a mens rea requirement at all, federal courts have applied certain presumptions and general principles that guide them in determining which elements of a crime must meet a mental-state requirement. First, the Supreme Court has made clear that the presumption in favor of scienter applies to "each of the statutory elements that criminalize otherwise innocent conduct."¹³³ Put another way: "Absent clear congressional intent to the contrary, statutes defining federal crimes are . . . normally read to contain a mens rea requirement that attaches to enough elements of the crime that together would be sufficient to constitute an act in violation of the law."¹³⁴ For instance, in United States v. Bruguier, a federal appellate court concluded that a federal statute proscribing "knowingly" engaging in a sexual act with another person "if that other person is . . . incapable of appraising the nature of the conduct" or physically incapable of expressing lack of consent¹³⁵ required both knowingly engaging in the sexual act and knowledge that the other person could not appraise the nature of the conduct or express lack of consent.¹³⁶ In reaching this conclusion, the court noted that knowingly engaging in a sexual act with another person "is not inherently criminal under federal law, barring some other attendant circumstance."¹³⁷ By contrast, in United States v. Feola, the Supreme Court determined that a statute criminalizing assault on a federal officer "while engaged in or on account of the performance" of official duties¹³⁸ did not require the assailant to be aware that the victim was a federal officer, emphasizing that a perpetrator "knows from the very outset that his planned course of conduct is wrongful" and thus the "situation is not one where legitimate conduct becomes unlawful solely because of the identity of the individual or agency affected."¹³⁹

The distributive approach emphasizing a distinction between elements that make conduct criminal (as in Bruguier, where incapacity and knowledge thereof made conduct criminal that otherwise was not inherently so) and elements that "merely aggravate[] conduct that already is criminal" (as in Feola, where the element at issue merely defined a subset of assaults as federally punishable) has been subject to criticism for its lack of clarity.¹⁴⁰ Recent Supreme Court cases have at times appeared to skirt the lack of clarity and move towards a rule more akin to the MPC approach—i.e., that, absent an indication of congressional intent to the contrary, a mental-state requirement applies to each material element of the offense.¹⁴¹ For example, in Flores-Figueroa v. United States, the Court addressed a provision imposing a mandatory two-year prison term on certain persons who "knowingly transfer[], possess[], or use[], without lawful authority, a means of identification of another person."¹⁴² In a largely textual analysis, the Court concluded that the statute required proof that the defendant knew that the "means of identification" belonged to another person, based in part on the recognition that "courts ordinarily read a phrase in a criminal statute that introduces the elements of a crime with the word 'knowingly' as applying that word to each element."¹⁴³ Some observers subsequently noted that this language could be viewed as "parallel[ing] the distributive default of the Model Penal Code,"¹⁴⁴ though several Justices wrote separately in the case to make clear that they did not necessarily agree with the language as a "normative description of what courts should ordinarily do when interpreting such statutes."¹⁴⁵ The federal courts of appeals have largely recognized that Flores-Figueroa's language does not "establish a bright-line rule that a specified mens rea always applies to every element of the offense."¹⁴⁶ In contrast, in Torres v. Lynch, the Court explained that "[i]n general, courts interpret criminal statutes to require that a defendant possess a mens rea, or guilty mind, as to every element of an offense."¹⁴⁷ Moreover, in Rehaif v. United States, the Court indicated that the presumption of scienter as to an element "applies with equal or greater force when Congress includes a general scienter provision in the statute itself," citing the MPC provision that establishes a default distributive rule applying to all material elements.¹⁴⁸ The Court in Rehaif also gestured to the "innocent conduct" analysis, however, in concluding that the statute at issue—which penalized "knowing[]" violations of a provision proscribing firearm possession by aliens unlawfully in the United States—required application of the knowledge standard to both the defendant's conduct and immigration status, specifying that "the possession of a gun can be entirely innocent" and thus applying mens rea to immigration status helped "separate wrongful from innocent acts."¹⁴⁹

Regardless of whether or when a presumption of scienter attaches to other elements of a criminal offense, what is clear is that no presumption applies with respect to jurisdictional elements—i.e., elements that "simply ensure that the Federal Government has the constitutional authority to regulate the defendant's conduct" by, for instance, limiting an offense to conduct "in or affecting commerce."¹⁵⁰ As the Court in Rehaif stated: "Because jurisdictional elements normally have nothing to do with the wrongfulness of the defendant's conduct, such elements are not subject to the presumption in favor of scienter."¹⁵¹

Meaning of Mens Rea Standards in Federal Statutes

Beyond the questions of whether a statute contains mens rea requirements and, if so, which elements carry those requirements is the question of what the mens rea standards established under federal law actually mean. Many of the dozens of different mens rea terms in federal law are undefined.¹⁵² Further, the terms used may be conclusory and give little indication of what mental state is called for—for instance, terms such as "corruptly," "maliciously," "unlawfully," and "feloniously" can all be found in Title 18 alone.¹⁵³ As such, understanding what mental state is required for a given federal crime will almost necessarily require reference to judicial opinions construing that particular provision. Even then, "the same terms are defined differently depending on which substantive crime is at issue, which federal circuit one is in, and which judge within a given district is crafting the jury's instructions."¹⁵⁴

As the National Commission on Reform of Federal Criminal Laws acknowledged decades ago, however, judicial opinions interpreting federal mens rea terms "display far fewer mental states than the statutory language" might suggest.¹⁵⁵ Of "paramount importance" in federal criminal law are the concepts of "intention" or, in the language of the MPC, "purpose," "as well as knowledge or awareness."¹⁵⁶ Less common, though still relevant, are concepts embodied at least partially in the MPC's frameworks for recklessness and negligence.¹⁵⁷ Different courts may have different approaches to these concepts and the definitions they entail. This section provides an overview of the meanings of some of the most common mens rea standards under federal law, grouped loosely into categories similar to those recognized in the MPC.

Intentionally, Knowingly, and Willfully

The terms "intentionally," "knowingly," and "willfully" are among those "used most frequently" in federal criminal statutes, but as with other federal mens rea terms, they have "eluded precise definition."¹⁵⁸ It seems that all three terms require at least some degree of conscious, subjective awareness of the element to which the requirement attaches.¹⁵⁹ Beyond this baseline, the meanings of the terms may vary or overlap considerably depending on the court, statute, and context of their use.¹⁶⁰

Intentionally and Knowingly

The concept of committing an offense "intentionally" has long been mired in confusion given the varying usages of the term at common law and the rather unclear distinction between "specific intent" and "general intent" crimes.¹⁶¹ In one view, intent might be thought to embody a "bifurcated concept" embracing a requirement that a person "consciously desire[]" some result or that they be aware that it "is practically certain," whatever their desire.¹⁶² Under this approach, any "limited distinction" between knowledge and intention or purpose is not "considered important since 'there is good reason for imposing liability whether the defendant desired or merely knew of the practical certainty of the results.'"¹⁶³ An ostensible blurring of the concepts of intention and knowledge is embodied in some federal court jury instructions that define "knowingly" as "voluntarily and intentionally,"¹⁶⁴ as well as cases that may treat the term "intent" as "requir[ing] only that the defendant reasonably knew the proscribed result would occur" or as requiring that the defendant "specifically intended such an outcome as his purpose" depending on the common-law categorizations of specific versus general intent.¹⁶⁵ This approach may lead to disagreement as to whether particular federal statutes with an intent requirement call for merely awareness or a higher degree of purpose or desire,¹⁶⁶ though courts have often applied a general intent standard as a default.¹⁶⁷

The approach¹⁶⁸ largely reflected in the MPC and some federal precedent is to distinguish between "intention" or purpose on the one hand as being limited to a conscious object or desire, and "knowledge" on the other hand as capturing a requirement of awareness of a high probability or to a practical certainty.¹⁶⁹ The Supreme Court in Bailey referenced this distinction approvingly and suggested that intention or purpose "corresponds loosely with the common-law concept of specific intent, while 'knowledge' corresponds loosely with the concept of general intent."¹⁷⁰ Some federal courts utilize a definition of "knowing" that approximates the MPC approach, instructing that to act knowingly a defendant must have "realized what he was doing and [be] aware of the nature of his conduct" rather than acting "through ignorance, mistake or accident."¹⁷¹ Congress has also signaled an intent to distinguish between the two mens rea terms in this way in particular statutes. For instance, prior to 1986, the Computer Fraud and Abuse Act (CFAA) proscribed "knowingly" accessing a computer without authorization or exceeding authorized access in certain circumstances.¹⁷² In its 1986 amendments, however, Congress changed the standard from "knowingly" to "intentionally," and the Senate report emphasized that the change was meant to require "more than that one voluntarily engaged in conduct . . . . Such conduct . . . must have been the person's conscious objective."¹⁷³

For federal statutes that establish a "knowing" mens rea requirement, one issue that can arise concerns a circumstance where a person may not have positive knowledge of the element at issue "only because he consciously avoided it."¹⁷⁴ In this situation, every federal circuit has recognized that so-called "willful blindness" or "deliberate ignorance" can equate to knowledge.¹⁷⁵ Though the precise formulations and requirements vary, courts "appear to agree on two basic requirements: (1) The defendant must subjectively believe that there is a high probability that a fact exists and (2) the defendant must take deliberate actions to avoid learning of that fact."¹⁷⁶ For instance, if a person is found to be transporting narcotics in the trunk of their car and claims that their suspicions were aroused by the smell of dryer sheets used to mask the narcotics' odor but that they did not actually know the trunk contained drugs, a willful blindness jury instruction may be appropriate in a subsequent prosecution for knowing possession of a controlled substance under 21 U.S.C. § 841(a)(1).¹⁷⁷ A rationale frequently given for the doctrine is that "persons who know enough to blind themselves to direct proof of critical facts in effect have actual knowledge of those facts."¹⁷⁸

Willfully

Beyond "knowingly" and "intentionally," another of the most commonly used mens rea terms in federal criminal law is "willfully,"¹⁷⁹ which may appear as a standalone term¹⁸⁰ or in conjunction with "knowingly."¹⁸¹ The term also exemplifies, perhaps better than any other, the non-uniformity of mental-state requirements under federal law. As the Supreme Court has recognized, the "word 'willfully' is sometimes said to be 'a word of many meanings' whose construction is often dependent on the context in which it appears."¹⁸² Other courts have referred to the term more colorfully as "notoriously slippery" and a "chameleon word."¹⁸³ As the National Commission on Reform of Federal Criminal Laws summarized it, courts "have endowed the requirement of willfulness with the capacity to take on whatever meaning seems appropriate in the statutory context," providing "[p]erhaps the best illustration of the confusion engendered by existing statutory formulations of the mental element" in federal criminal law.¹⁸⁴

In a common formulation, "a 'willful' act is one undertaken with a 'bad purpose,'" meaning that to act "willfully" requires "knowledge that [one's] conduct was unlawful."¹⁸⁵ This formulation distinguishes the term "willfully" from a common conception of "knowingly" under federal law, as the latter ordinarily requires only knowledge of the facts that constitute an offense.¹⁸⁶ The typical knowledge-of-unlawfulness formulation of "willfully" does not, however, require knowledge of the precise legal provision or prohibition that has been violated.¹⁸⁷ Rather, all that is required is knowledge that conduct is unlawful "in some general sense."¹⁸⁸

Courts have identified additional "levels of interpretation" of "willfully."¹⁸⁹ In some contexts the term may merely "denote an act which is intentional, or knowing, or voluntary, as distinguished from accidental"—in other words, it may be synonymous with other mens rea standards discussed in this section.¹⁹⁰ By contrast, in the context of "highly technical statutes that present[] a danger of ensnaring individuals engaged in apparently innocent conduct,"¹⁹¹ courts have recognized a heightened formulation of "willfulness" that requires "proof that the defendant actually knew of the specific law prohibiting the conduct."¹⁹² For instance, in Cheek v. United States, the Supreme Court determined that statutory provisions of the tax code criminalizing willful tax evasion and willful failure to file returns required "actual knowledge of the pertinent legal duty," as the complexity of the tax laws "made it difficult for the average citizen to know and comprehend the extent of the duties and obligations imposed" by those laws.¹⁹³

Example of Courts' Construction of Arson Statute, 18 U.S.C. § 81

An example of the complications that may arise in construing federal statutes that require some level of intentionality or awareness can be found in dueling court constructions of 18 U.S.C. § 81.¹⁹⁴ That statute prohibits "willfully and maliciously sett[ing] fire to or burn[ing] any building, structure or vessel," among other things, in a certain federal jurisdictional context.¹⁹⁵ In United States v. M.W., the Tenth Circuit¹⁹⁶ construed the statute's "willfully and maliciously" mens rea requirement in the case of a student who broke into a school located on an Indian reservation and set fire to school records in the principal's office.¹⁹⁷ The fire got out of control and resulted in extensive damage to the school building.¹⁹⁸ The district court found the student guilty of arson under 18 U.S.C. § 81 and, on appeal, the student argued that the statute required him to have "the intent to burn [the] building," which he did not have because he only intended to burn the records.¹⁹⁹ The Tenth Circuit applied the MPC approach and determined that (1) knowledge was sufficient to meet the willfulness requirement, and (2) because burning the building was a result element, the student could be convicted if he was "aware that it [was] practically certain that his conduct" would cause that result.²⁰⁰ In other words, the Tenth Circuit construed the "willfully and maliciously" term as requiring only knowledge—i.e., awareness to a practical certainty—that conduct would result in setting fire to a building and upheld the student's conviction based on the lower court's finding that he had such awareness.²⁰¹

By contrast, in United States v. Doe (R.S.W.), the Ninth Circuit construed the same statute in similar factual circumstances as requiring neither intent to burn a building nor "knowledge this would be the probable consequence of the defendant's act."²⁰² Rather, according to the court, all that the "willfully and maliciously" term required was general intent to do the act that caused a building to burn, i.e., "that the defendant set the fire intentionally and without justification or lawful excuse."²⁰³ In reaching this conclusion, the court expressly rejected reliance on the MPC, observing that because the mens rea term was drawn from the common law definition of arson, the court should assume that Congress "knew how the common law defined that phrase" and "intended to adopt the [general-intent] meaning that common law gave" it when enacting 18 U.S.C. § 81.²⁰⁴ In dissent, one judge argued that the court's construction effectively turned the statute into a strict liability offense, as the majority mistakenly applied a standard of intentionality "not to the proscribed conduct of setting fire to a building, but to [the defendant's] mental state toward setting [items in the building] aflame."²⁰⁵

As these two cases reflect, mens rea terms like "intentionally," "knowingly," and "willfully" may overlap or blend into each other, and judicial interpretations of such terms may differ markedly even as applied to the same statute under very similar factual circumstances. Thus, in M.W., the court viewed "willfully and maliciously" as requiring only knowledge, but it treated that knowledge requirement as extending to the result of a building being burned, while in R.S.W., the court purported to treat "willfully and maliciously" as synonymous with intention but concluded that intention (in the sense of voluntariness) with respect to the act of lighting the fire was sufficient to meet the statute's mens rea requirement.

Recklessly and Negligently

Though the mens rea concepts of recklessness and negligence are much less central in federal criminal law than are concepts of intention or knowledge,²⁰⁶ some federal criminal provisions do utilize them.²⁰⁷ In general, recklessness and negligence are distinct from other mens rea standards in that they focus on risk.²⁰⁸ Nonetheless, recklessness shares with higher forms of mens rea a requirement of subjective awareness, while negligence is often understood to establish an objective standard that arguably takes it out of the realm of a true "mental-state" requirement altogether.²⁰⁹

Recklessly

According to the Supreme Court, the "dominant formulation" of a mens rea requirement of recklessness is that one "consciously disregard[s] a substantial risk" of harm.²¹⁰ This formulation is drawn from the MPC, which defines recklessness as conscious disregard of "a substantial and unjustifiable risk" that an element exists or will result from one's conduct.²¹¹ It appears that federal courts largely use this definition, or one that is substantially similar, in construing federal statutes that contain the term "reckless" or "reckless disregard."²¹² As the definition suggests, criminal recklessness under federal law generally requires subjective awareness of a risk and deliberate disregard of it, i.e., "the intentional taking of a risk that might result in harm,"²¹³ though there may be some variation among courts and across statutes as to whether awareness of facts and circumstances giving rise to a risk is sufficient to establish recklessness in the absence of awareness of the risk itself.²¹⁴

Recklessness thus differs from a mens rea standard of "knowledge" primarily in regard to the degree of certainty of a circumstance or outcome of which a defendant is aware—in the MPC formulation that is sometimes used by federal courts, knowledge connotes awareness of a high probability or to a practical certainty; recklessness, by contrast, focuses on awareness of some lesser degree of risk.²¹⁵ For example, the Fourth Circuit in United States v. Carr considered a federal statute prohibiting intentionally damaging or destroying certain buildings by means of fire or an explosive and causing the death of any person.²¹⁶ The case required the court to distinguish between a knowing and reckless state of mind with respect to the death that occurred for sentencing purposes.²¹⁷ The district court found that the defendant, who set fire to an apartment building resulting in the death of an occupant, was "recklessly indifferent to whether people would be in the apartment building" because the mailboxes, gas meters, and cars out front made it "obvious" the structure was occupied.²¹⁸ The district court viewed this "reckless indifference" as "equat[ing] to knowledge" and thus refused to consider a lower sentence that could apply for recklessly causing death.²¹⁹ On appeal, the Fourth Circuit rejected the lower court's conflation of recklessness and knowledge, making clear that although both standards "require a subjective awareness of risk on the part of the actor," the "degree of the risk that the actor is aware of" (i.e., a substantial risk versus practical certainty) distinguishes the two.²²⁰ The court held that, although the lower court's findings regarding indicia of occupancy like mailboxes "certainly support[ed] a finding of recklessness," its failure to make a finding on the question of whether the evidence supported the higher standard of knowledge (i.e., whether he acted "with an awareness that death was practically certain to result") was erroneous.²²¹

Given that the primary distinction between common definitions of knowledge and recklessness focuses on the degree of risk of a particular outcome, at least one circuit has held that, in determining the sufficiency of the evidence, "a finding that an accused acted recklessly may be enough to sustain a jury verdict" pursuant to a statute that requires knowledge "because a jury may properly infer the requisite intent."²²² Any boundary between the two levels of culpability may also be further blurred in some instances—for example, the Sixth Circuit has interpreted a statute proscribing (among other things) knowing failure to disclose information required under Title I of the Employee Retirement Income Security Act of 1974 as requiring only "proof of a voluntary conscious failure to disclose without ground for believing that such non-disclosure is lawful, or with reckless disregard for whether or not it is lawful."²²³ In other words, a "knowing" mens rea requirement may be construed in particular contexts to require only recklessness with respect to a circumstance or result, as may a "willfulness" requirement in some cases.²²⁴

Negligently

Negligence is a concept that will likely be most familiar to those acquainted with tort law.²²⁵ It can also have criminal applications, although negligence as a federal mens rea standard is less prevalent than other terms discussed in this report.²²⁶ At the most basic level, negligence embodies (1) conduct that is "judged by an objective (reasonable man) standard," and (2) some "degree of risk which the defendant's conduct must create."²²⁷ One conception of negligence in the criminal context, reflected in the MPC, is that the defendant "should be aware" of a risk that the statutory element at issue exists or will result from his conduct.²²⁸ According to this view, the "basic distinction" between recklessness and negligence is that a defendant "is criminally negligent when he should have been aware of the risk but was not, while recklessness requires that the defendant actually be aware of the risk but disregard it."²²⁹ Whether a defendant "should have been aware" is, in turn, judged by the objective standard of a reasonable person.²³⁰ The MPC approach to negligence also emphasizes that the risk must be "substantial and unjustifiable," i.e., the risk must be "of such a nature and degree" that failure to perceive it "involves a gross deviation from the standard of care that a reasonable person would observe in the actor's situation."²³¹ These elaborations may be said to embody a heightened standard of "gross" or "criminal" negligence, as distinguished from the ordinary negligence typically sufficient for civil liability that, in one representative formulation, requires only "doing something which a reasonably prudent person would not do, or . . . failing to do something which a reasonably prudent person would do."²³²

Some have suggested that an "ordinary" negligence standard is inappropriate for imposition of criminal liability, arguing that criminalizing mere failure to exercise ordinary care has "limited deterrent value" and is "fundamentally unfair."²³³ Nevertheless, "the notion that criminal liability might extend in special circumstances to simple negligence . . . is a surprisingly long-standing feature of federal statute, with a similarly long history of favorable treatment by the Supreme Court."²³⁴ As such, to the limited extent negligence is employed in federal law as a mens rea standard for criminal prohibitions, it may be interpreted as requiring only ordinary negligence in the absence of an indication of legislative intent to impose a higher standard.²³⁵ However, there is no uniform conception of negligence in federal criminal law. As with the other mens rea standards discussed in this report, formulations may vary by court or statute²³⁶ and may overlap with conceptions of more culpable mental states like recklessness. For instance, 18 U.S.C. § 1112 defines involuntary manslaughter as "the unlawful killing of a human being without malice . . . in the commission in an unlawful manner, or without due caution and circumspection, of a lawful act which might produce death."²³⁷ Several courts have interpreted the statute as imposing a mens rea requirement of "gross negligence" but have defined that requirement in at least partially subjective terms.²³⁸

Example of Courts' Construction of Occupational Safety & Health Act, 29 U.S.C. § 666(e)

An illustrative example of the dividing lines between recklessness, negligence, and higher levels of culpability in federal criminal law can be found in a Seventh Circuit decision addressing the Occupational Safety & Health Act (OSHA), which establishes (among other things) criminal penalties for employers who "willfully violate[]" health and safety standards or regulations such that death of an employee results.²³⁹ In United States v. Ladish Malting Co., the Seventh Circuit reviewed jury instructions that defined "willfully" as "knowingly and voluntarily" in "reckless disregard" of relevant requirements, further defined "reckless disregard" in part as "having knowledge" of a hazardous working condition, and defined "having knowledge" of such condition to mean that the employer "knew or should have known of the hazardous condition."²⁴⁰ In other words, the instructions permitted a conviction if the jury concluded that the employer "should have known" of a dangerous condition and "reasonably should have known" that the condition violated federal requirements.²⁴¹

The appellate court concluded that these instructions regarding the requisite mens rea with respect to the hazardous working condition at issue were erroneous.²⁴² The court determined that defining "knowledge" in terms of what one "knew or should have known" improperly rendered the statutory willfulness requirement synonymous with ordinary negligence.²⁴³ According to the Seventh Circuit, the instructions "equated willfulness with knowledge, watered down knowledge to recklessness, defined recklessness as negligence, and used the civil rather than the criminal approach to negligence" by failing to add the "standard gloss" of a heightened negligence standard applicable in criminal cases.²⁴⁴ The court stated it was "essential to preserve the difference" between these standards by requiring that knowledge mean actual knowledge or willful blindness and that recklessness mean actual awareness of a risk, lest "knowledge, recklessness, criminal negligence, and civil negligence . . . merge into a single mental state[.]"²⁴⁵ As such, the court concluded that "[t]ransforming" willfulness to ordinary negligence was "inappropriate both in principle and for [OSHA] in particular."²⁴⁶

Other Mens Rea Standards

As described previously, because the U.S. Code does not generally employ the standardized culpability rules and definitions found in the MPC, federal mens rea requirements are largely statute-specific.²⁴⁷ Congress has also, at times, used state-of-mind language in particular statutes that either does not clearly signal which level of culpability is intended or that appears to establish a state-of-mind requirement that does not fit neatly into one of the categories described above, leaving courts to attempt to interpret the language in a way that comports with congressional intent. As a result, specific federal crimes, as defined or as interpreted by the federal courts, may bear mental-state requirements that appear to blend components of more than one standard.²⁴⁸

For instance, several federal statutes prohibit conduct engaged in with either intent or knowledge, or with "reason to believe," "reasonable cause to believe," or "reason to know" of some attendant circumstance or result.²⁴⁹ Court decisions have displayed a degree of confusion as to where this language falls on the continuum between actual knowledge and an objective, "reasonable person" standard closer to negligence. The Tenth Circuit, for instance, construed a statute that prohibits possession or distribution of listed chemicals "knowing, or having reasonable cause to believe," they will be used to manufacture a controlled substance as involving a "subjective inquiry" that "requires scienter to be evaluated through the lens of th[e] particular defendant, rather than from the prospective of a hypothetical reasonable man."²⁵⁰ In other words, the court viewed the mens rea standard of "reasonable cause to believe" as "akin to actual knowledge,"²⁵¹ requiring subjective knowledge "or something close to it" that the chemical at issue would be used to manufacture a controlled substance.²⁵² However, the court in a subsequent case addressing a statute that proscribes filing a false lien against a federal officer or employee "knowing or having reason to know" of its falsity,²⁵³ interpreted the statute as permitting conviction "if a reasonable person who possessed the information possessed by the defendant would have the requisite knowledge of falsity," i.e., the court treated the mens rea standard of "knowing" or "having reason to know" as having "both a subjective component (that is, what information this particular defendant had) and an objective component (what a reasonable person would infer from that information)."²⁵⁴ In dicta, the court distinguished language from its earlier decisions that suggested a different reading and maintained that prior holdings were consistent with the proffered interpretation.²⁵⁵

Other circuits have agreed with a conception of "reasonable cause to believe" as a hybrid subjective/objective standard, emphasizing that the inquiry "turns on the facts actually known by the defendant in a particular case—facts from which the jury can infer that any reasonable person in the defendant's position would have had to know . . . ."²⁵⁶ At least one district court has made clear, however, that a similar standard in a statute prohibiting delivery of defense information to a foreign government or actor "with intent or reason to believe that it is to be used" in a particular way is not a negligence standard, as it requires the jury to "find that defendant personally and subjectively believed or should have believed" the information was to be used for the prohibited purpose.²⁵⁷

Selected Additional Mens Rea Issues in Federal Law

In addition to the questions of what mental states are required for federal offenses and what they mean, distinct issues arise for certain classes of offenses and species of federal criminal liability—specifically, inchoate crimes, such as attempt and conspiracy, and corporate liability. Mental state considerations also can be relevant to an alleged offender's defense to criminal liability.

Inchoate Crimes

Under federal law, it is a separate crime to conspire to commit any other federal crime, i.e., to agree with another to commit the crime and typically to take some overt action in furtherance of its commission.²⁵⁸ Likewise, though there is no general federal attempt provision, attempts to commit many of the most common federal crimes are proscribed in individual statutes.²⁵⁹ These crimes, which existed at common law, are said to be "inchoate" in the sense that they are "crimes on their way to becoming other crimes unless stopped or abandoned."²⁶⁰ Because these offenses, in a general sense, encompass the contemplation or objective of committing another crime, they are sometimes said to require a "heightened mental state" that, in the words of the Supreme Court, "separates criminality itself from otherwise innocuous behavior."²⁶¹ The MPC reflects this notion in its conspiracy and attempt provisions by generally requiring the highest level of culpability, "purpose"—to promote or facilitate commission of an offense (in the case of conspiracy) or to engage in conduct or cause a result (in the case of attempt).²⁶²

In federal law, the mens rea for inchoate crimes is often couched in the language of "specific intent."²⁶³ More precisely, an attempt to commit a federal crime has been framed as taking "a substantial step towards completion of the offense" while acting "with the specific intent to commit the underlying crime,"²⁶⁴ and a conspiracy, among other things, "requires proof of specific intent to further the conspiracy's objective."²⁶⁵ Given the multiple and sometimes indeterminate meanings and usages of the term "specific intent,"²⁶⁶ however, federal courts may disagree on what is required to prove the mental state for an inchoate crime in a particular statutory context. For instance, 8 U.S.C. § 1326 criminalizes reentry and attempted reentry into the United States by aliens who have been removed and lack express permission from the Attorney General to reapply for admission to the country.²⁶⁷ The federal courts of appeals generally agree that prohibited reentry under the statute is a general intent crime—i.e., one must have an intent to enter but does not need to intend to enter unlawfully (in other words, without the permission of the Attorney General).²⁶⁸

Courts are split, however, on the requisite mental state for attempted reentry under Section 1326. The Ninth Circuit has reasoned that consistent with the common law meaning of "attempt," which requires a specific intent to commit the underlying crime, attempted reentry under Section 1326 requires, among other things, that "the defendant had the purpose, i.e., conscious desire, to reenter the United States without the express consent of the Attorney General."²⁶⁹ Yet other circuits have diverged from this interpretation. For example, the Second Circuit concluded in United States v. Rodriguez that because Section 1326 establishes a crime unknown at common law, the "words in the statute are liberated from their common law meanings."²⁷⁰ As such, based on the perceived "clarity of the statutory language" and considerations of statutory purpose, the court in Rodriguez determined that Section 1326 requires only intent to reenter, that there is "no specific intent requirement for attempted reentry," and the government is not obligated to establish a defendant's mental state with respect to lack of consent or permission.²⁷¹ The Second Circuit framed this conclusion as a rejection of the proposition that Section 1326's attempt provision incorporates a specific intent requirement,²⁷² though at least one other circuit has appeared to treat attempted reentry as "a specific intent crime" while still construing the requisite intent as extending only to "achiev[ing] entry into the United States."²⁷³

With regard to conspiracy, the so-called "Pinkerton doctrine" (in reference to a famous Supreme Court case) actually provides somewhat of a mens rea exception for separate substantive offenses committed in the course of a conspiracy. Under the doctrine, criminal liability is extended "to a conspirator for a coconspirator's substantive offenses 'when they are reasonably foreseeable and committed in furtherance of the conspiracy.'"²⁷⁴

Corporate Liability

Many federal criminal statutes apply to "whoever" or to any "person" who engages in prohibited conduct.²⁷⁵ Title 1 of the U.S. Code provides that unless the context of an Act of Congress indicates otherwise, "the words 'person' and 'whoever' include corporations, companies, associations, firms, partnerships, societies, and joint stock companies, as well as individuals."²⁷⁶ As such, corporate entities generally may commit, and be prosecuted for, federal criminal offenses, which raises the question of how legal entities that can act only through individuals can themselves be considered to have committed criminal conduct with the requisite mens rea. This question is one on which federal law deviates from the approach of the MPC. Under federal law, corporate criminal liability extends to offenses committed by a corporate officer, employee, or agent if acting within the scope of his or her authority at least partly for the benefit of the corporation.²⁷⁷ Where these conditions are met, the mens rea of the officer, employee, or agent engaging in the proscribed conduct is imputed to the entity for purposes of criminal liability,²⁷⁸ even if the entity's policies or compliance program deter such activity.²⁷⁹

A distinct issue "arises when no single employee possesses the requisite mens rea necessary for the offense but a number of employees have, together, committed the unlawful act."²⁸⁰ In this circumstance, at least one circuit has endorsed a theory of "collective" knowledge by which the scienter of individual employees may be aggregated.²⁸¹ Other courts have been dubious of this theory, particularly as applied to culpability standards beyond knowledge.²⁸²

The MPC takes a different approach to corporate criminal liability (and, accordingly, mens rea). Section 2.07 of the MPC limits corporate liability for most kinds of crimes to situations where "the offense was authorized, requested, commanded, performed or recklessly tolerated by the board of directors or by a high managerial agent acting in behalf of the corporation within the scope of his office or employment."²⁸³ This "inner circle" approach to corporate liability has been criticized by some as underinclusive, given modern-day corporate realities.²⁸⁴

Defenses

A defendant's mental state can be relevant to his or her asserted defense to criminal liability in several respects, depending on the nature of the defense at issue. In one regard, affirmative defenses such as self-defense and necessity have their own mental components that are separate from the mens rea required for commission of the charged crime. For instance, the Tenth Circuit's formulation of the requirements for self-defense as a defense to a federal homicide charge includes that the defendant "reasonably believes that he is in imminent danger of death or great bodily harm, thus necessitating an in-kind response."²⁸⁵ In other words, even where the defendant indisputably possesses the requisite mens rea for a federal crime involving the use of force against, or causing the death of, another, the defendant is not guilty of the crime if he or she subjectively believed the force used was necessary and that belief was objectively reasonable under the circumstances.²⁸⁶ Additional defenses such as duress and necessity likewise do not ordinarily "negate a defendant's criminal state of mind" but allow "the defendant to avoid liability"²⁸⁷ based on conditions that justify the criminal conduct and involve proof (among other things) of certain objectively reasonable beliefs on the defendant's part.²⁸⁸ Statutory defenses established by Congress and applicable only to specific federal offenses may also necessitate proof of some mental state independent of the mens rea required for commission of the crime. For example, 18 U.S.C. § 2243(a) prohibits, in certain jurisdictional contexts, knowingly engaging in a sexual act with another person who is between 12 and 15 years old when there is at least a four-year age difference between the two people.²⁸⁹ The mens rea required for commission of the crime is knowingly engaging in the sexual act; the defendant need not have known the age of the victim or the age difference.²⁹⁰ However, the statute provides a defense if "the defendant reasonably believed that the other person had attained the age of 16 years."²⁹¹

Other defenses to federal criminal liability focus on circumstances that negate the defendant's mens rea with respect to the charged crime. Voluntary intoxication, for instance, is generally recognized by the federal courts as a defense that may negate the mens rea of a specific-intent, but not a general-intent, crime.²⁹² A mistake may operate similarly.²⁹³ The federal insanity defense, codified at 18 U.S.C. § 17, recognizes a defense for persons with conditions that may negate the requisite mens rea and conditions that have been deemed independently to justify declining to impose criminal liability. The statute provides an affirmative defense if a "severe mental disease or defect" leaves the defendant "unable to appreciate" either (1) the "nature and quality" of his acts or (2) "the wrongfulness" of his acts.²⁹⁴ The first prong, referred to by the Supreme Court as the "cognitive capacity" prong, involves an inquiry into "whether a mentally ill defendant could comprehend what he was doing when he committed a crime," for if he "had no such capacity, he could not form the requisite intent—and thus is not criminally responsible."²⁹⁵ The second prong, "moral capacity," looks to whether the defendant, regardless of his awareness of the nature of his conduct or intent to do the proscribed act or bring about the proscribed result, could "distinguish right from wrong when committing his crime."²⁹⁶ At least one circuit has concluded that "wrongfulness for purposes of the federal insanity defense statute is defined by reference to objective societal or public standards of moral wrongfulness, not the defendant's subjective personal standards of moral wrongfulness."²⁹⁷ Thus, under this conception, what the defendant would personally believe to be right and wrong is irrelevant.

Federal Mens Rea Reform and Considerations for Congress

After the efforts of the congressionally created National Commission on Reform of Federal Criminal Laws did not yield significant changes to federal mens rea requirements in the 1970s,²⁹⁸ some commentators continued to urge reforms consistent with, or building on, the MPC approach.²⁹⁹ In 2013, the House Judiciary Committee established a "bipartisan task force on over-criminalization" to review "current federal criminal statutes and make recommendations for improvements."³⁰⁰ One of the issues the task force reviewed was "the lack of a consistent and adequate mens rea requirement in the federal code."³⁰¹ Relying on the work of the task force, "a Criminal Justice Reform Initiative at the Judiciary Committee" was created in early 2015 "to address the significant Congressional interest in criminal justice reform from Members who do and do not serve on the Judiciary Committee."³⁰² Several bills stemming from this and other legislative efforts³⁰³ in the 114th and 115th Congresses sought to make changes to the status quo with respect to federal mens rea requirements. Though the proposals varied in the details, they typically incorporated ideas and concepts stemming from the MPC approach to culpability. Ultimately, none of the bills from prior Congresses became law. However, consideration of altering federal mens rea requirements continues in the 117th Congress. On March 11, 2021, several Senators introduced the Mens Rea Reform Act of 2021,³⁰⁴ multiple versions of which had been introduced in earlier Congresses. This section describes the pending bill in the current Congress, provides an overview of earlier legislation from the 114th and 115th Congresses³⁰⁵ that would have impacted federal mens rea requirements, and briefly sets out some considerations for Congress reflected in these legislative efforts.

117th Congress

The Mens Rea Reform Act of 2021 would establish that for elements of most federal criminal offenses "for which the text . . . does not specify a state of mind," a default mens rea of "willfully" would apply.³⁰⁶ The bill would define "willfully" as knowledge of unlawfulness and, for elements involving the nature, circumstances, object, or result of conduct of a person, that the person knew of and had as his or her conscious object the accomplishment of conduct of that nature, with those circumstances, or with the object or result.³⁰⁷ In other words, the bill sets as a default mens rea standard that one act purposely and with knowledge that one's conduct is unlawful. The bill also provides that where a mens rea term is present but the text of the offense does not specify the elements to which it applies, the term applies to all elements unless "a contrary purpose plainly appears."³⁰⁸ Exception is made to both the default mens rea term and default application rules if (1) the text makes clear that no state of mind was meant to be required for such element, (2) the element establishes jurisdiction or venue, or (3) applying either rule would "lessen the degree of mental culpability" for that element under Supreme Court precedent or existing statutory or regulatory law.³⁰⁹ With respect to the exception for textual clarity that no state of mind is required, the bill would specify that "the mere absence of a specified state of mind for an element of a covered offense in the text of the covered offense shall not be construed to mean that Congress affirmatively intended not to require the Government to prove any state of mind with respect to that element."³¹⁰ Put differently, for Congress to provide for strict liability for an element of a federal offense, it would need to explicitly denote in the text of the offense that no mens rea is required for that element. The bill would expressly apply to existing offenses,³¹¹ meaning that some federal offenses silent as to mens rea that had previously been interpreted as strict liability could now carry a heightened state-of-mind requirement, were the bill to become law.³¹²

114th and 115th Congresses

An earlier version of the bill from the 117th Congress was first introduced in the 114th Congress. The Mens Rea Reform Act of 2015³¹³ would have required (with some exceptions) that with respect to any element for which the text of an offense "does not specify a state of mind," the government must prove that the defendant acted willfully.³¹⁴ The bill also would have established a default distribution rule when application of a term is unclear. Specifically, where a covered offense specifies the requisite mens rea but does not specify to which elements of the offense the requirement applies, the bill would have required that the requisite mens rea "apply to all elements of the covered offense" subject to exceptions including a plain contrary purpose in the statute and jurisdictional elements, among other things.³¹⁵ The version of the Mens Rea Reform Act from the 114th Congress would have provided definitions for certain mens rea terms as well, defining the term "knowingly" as awareness with respect to conduct and circumstance elements and awareness that conduct is practically certain to cause a result with respect to result elements, in a manner largely consistent with the MPC's approach.³¹⁶ The bill also would have defined "willfully" for purposes of the default mens rea requirement as "knowledge that the person's conduct was unlawful."³¹⁷

Another bill from the 114th Congress, The Stopping Over-Criminalization Act of 2015, H.R. 3401, would have imposed a default mens rea requirement of knowledge in the absence of specification otherwise "in the provision of law defining the offense," though offenses "where a defendant might reasonably be unaware the conduct could be criminally punished" would have required proof that "the defendant had reason to know the defendant's conduct was unlawful."³¹⁸ The bill would have applied its default state of mind to "each element of the offense" with exception only for specific provision otherwise in the law defining the offense.³¹⁹ The Criminal Code Improvement Act of 2015, also from the 114th Congress, would have established that if "no state of mind is required by law" for a federal criminal offense, "the state of mind the government must prove is knowing" unless the offense involves conduct that a reasonable person in the same or similar circumstances would not know or have reason to know was unlawful, in which case "the Government must prove that the defendant knew, or had reason to believe, the conduct was unlawful."³²⁰

The Criminal Code Improvement Act of 2015, H.R. 4002, was reported out of committee on November 18, 2015.³²¹ Proponents of the bill, and of mens rea reform more generally, urged that the existing lack of clarity as to the requisite mental state for certain crimes violates principles of fair notice and asserted that strict liability offenses or offenses with relatively minimal mental-state requirements represent part of a larger, concerning trend of federal over-criminalization that Congress should seek to remedy.³²² Opposition to establishing mental-state requirements that would apply across federal criminal law centered on the prospect that such requirements could make it harder to punish corporate actors under provisions meant to protect public health and welfare.³²³ Representatives of the Department of Justice noted the difficulties that applying newly formulated broad-brush mental-state requirements could create in pursuing some significant cases, suggesting that indiscriminate application of such rules to existing offenses could have unintended consequences.³²⁴ Ultimately, neither the Criminal Code Improvement Act of 2015 nor the other legislation discussed above from the 114th Congress became law.

The Mens Rea Reform Act was reintroduced in the Senate in the 115th Congress with some changes clarifying the definition of willfulness and the application of the requirement to existing offenses, among other things, but that bill likewise did not become law.³²⁵

Considerations for Congress

The bills discussed above, which sought or seek to address in different ways recurrent issues with respect to federal mens rea requirements, raise distinct interpretive questions that Congress might examine. One question is how stringent a default mental-state requirement should be where the statute is silent. As described previously, federal courts will ordinarily presume that a mens rea element is included in a criminal offense even if it is not explicit in the text, and usually that element is set at least at the level of knowledge.³²⁶ Two of the bills described above would appear to have codified that default by making knowledge the statutory standard unless otherwise provided, while the various versions of the Mens Rea Reform Act set out a higher default of willfulness but with different definitions (i.e., knowledge of unlawfulness or, in the formulation from the bill pending in the 117th Congress, purpose and knowledge of unlawfulness).³²⁷ All of the aforementioned bills would have impacted the degree to which courts might recognize an exception to the presumption of scienter in the case of certain kinds of public-welfare offenses for which strict liability might ordinarily be deemed appropriate, as would the version of the Mens Rea Reform Act pending in the 117th Congress. Even the two bills that would have established a knowledge default for many kinds of offenses would appear to have disfavored the kinds of regulatory and public-welfare offenses for which courts might recognize strict liability, as many such offenses could be viewed as involving conduct that "a reasonable person . . . would not have reason to believe[] was unlawful" or "criminally punished" and would thus have been subject to a special rule requiring at least "reason to know" or "reason to believe" such conduct was, in fact, unlawful.³²⁸

A related question raised by the bills from the 114th and 115th Congresses and the bill pending in the 117th Congress is when a statute can be deemed silent on the question of mens rea such that a statutory default would apply. For instance, the Criminal Code Improvement Act of 2015 would have added a mental-state requirement to any federal criminal offense for which "no state of mind is required by law," but would not have made clear whether "required by law" would have been limited to offenses that are textually silent as to mental state or would have included judicial interpretations regarding an offense's mens rea requirement.³²⁹ The bill likewise would have had uncertain application to an offense with a mental-state requirement textually or judicially assigned to some, but not all, of its elements. The Mens Rea Reform Act of 2021 pending in the 117th Congress would address this issue by limiting its default mental-state requirement to "any element of the offense for which the text of the covered offense does not specify a state of mind," but exceptions would be made if, among other things, the result would "lessen the degree of mental culpability" required to be proven for a given element under other provisions of law or Supreme Court precedent.³³⁰

One version of the Mens Rea Reform Act from the 115th Congress would have modified the reach of its default requirement by providing that for existing offenses lacking a state-of-mind requirement for one or more elements either in the text of the offense or under Supreme Court precedent, a default mens rea of willfulness would apply in the absence of a contrary provision in statutory text or an applicable exception.³³¹ This provision potentially could have operated to overrule Supreme Court precedent with respect to its interpretation of existing federal crimes that lack a mental-state requirement for at least one element to the extent such precedent recognized a lower, or no, mens rea for that or another element.

Another question raised by the bills is whether, how, and under what circumstances to apply a distribution rule for a mens rea term whose application to certain elements of an offense is unclear. Currently, a federal court assessing whether a particular element of an offense carries a mens rea requirement will ask if it criminalizes otherwise innocent conduct, a statute-specific inquiry that may be less than pellucid.³³² The Mens Rea Reform Act of 2021 would eschew this approach in favor of a clearer distribution rule akin to the MPC position—a mens rea requirement in the text of a federal criminal offense would apply to each element of the offense unless an exception applied.³³³ Earlier versions of the Mens Rea Reform Act would have operated similarly,³³⁴ as would the Stopping Over-Criminalization Act of 2015.³³⁵ That latter bill would have made exception only where "otherwise specifically provided in the provision in the law defining the offense,"³³⁶ however, whereas the Mens Rea Reform Act of 2021 would make exception for elements relating to jurisdiction and venue and, among others, circumstances where the text of an offense makes clear that Congress "affirmatively intended" no mental-state requirement to apply or where application of the default would actually lessen the requisite mental state under Supreme Court precedent.³³⁷

As the above discussion reflects, even setting aside the prospect of more broadly systematizing and codifying mental-state term definitions in federal law, efforts to establish general application rules or default requirements in the absence of clear legislative drafting can raise a host of questions that Congress might examine in the 117th Congress in relation to the Mens Rea Reform Act of 2021 or any other legislation addressing the topic that might be introduced. As of this writing, no action has been taken on the Mens Rea Reform Act of 2021.