Mens Rea: An Overview of State-of-Mind Requirements for Federal Criminal Offenses

Mens Rea: An Overview of State-of-Mind

Requirements for Federal Criminal Offenses

July 7, 2021

Congressional Research Service

https://crsreports.congress.gov

R46836

SUMMARY

Mens Rea: An Overview of State-of-Mind

Requirements for Federal Criminal Offenses

R46836

July 7, 2021

Michael A. Foster

The concept of mens rea, or a “guilty mind,” reflects the idea that a crime generally must consist

Legislative Attorney

of not only a proscribed act but also a “mental element” sufficient to warrant punishment. Three

questions regularly arise with respect to the mental state required for a given federal crime: (1)

whether the statute establishing the crime contains a mental-state requirement, or requirements, at

all; (2) if the statute does contain mental-state requirements, which elements of the offense must

meet which requirements; and (3) what the mental-state requirements mean. Under federal law, determining the mental state

required for commission of a crime necessitates an examination of congressional intent.

Congressional intent can be difficult to discern given that federal criminal statutory law (largely codified at Title 18) contains

no uniform mens rea standards or generally applicable definitions of mental-state terms. Because federal statutory law lacks

general rules for assessing and applying mens rea terms and requirements across criminal statutes, courts have applied canons

of statutory interpretation and developed presumptions specific to mens rea when the state of mind requirement for a federal

offense is unclear. For example, when a criminal statute is silent on the question of what mental state is required, courts will

ordinarily apply a presumption in favor of scienter. The presumption counsels that typically some indication is required that

Congress intended to dispense with mens rea as an element of a crime, and simply omitting a mens rea term from the

statutory language will not be considered adequate evidence of such intent. Assuming the presumption of mens rea applies

and calls for a mental-state requirement to be read into a statute that does not expressly contain one, the question becomes

what kind of mental state is required. In this respect, the Supreme Court has said that the presumption requires “only that

mens rea which is necessary to separate wrongful conduct from ‘otherwise innocent conduct’”—typically, at least knowledge

of certain elements of the offense at issue.

With respect to which elements of a crime must meet a given mens rea requirement, the Supreme Court has stated that the

presumption in favor of scienter applies to “each of the statutory elements that criminalize otherwise innocent conduct,”

though such a distributive approach emphasizing a distinction between elements that make conduct criminal and those that do

not can sometimes be difficult to apply in practice. Finally, regarding what specific mental-state requirements mean, federal

law uses dozens of different mens rea terms that are frequently undefined. As such, reference to judicial precedent construing

the provision at issue is often required to understand what mental state is required for a particular federal crime. Even so,

federal mens rea requirements largely fall into loose categories that may include (1) an awareness of, or conscious purpose to

bring about, conduct, a circumstance, or a result that is a required element of the offense (commonly represented by terms

such as “intent,” “knowledge,” or “willfulness,” among others), or (2) an awareness and disregard of a substantial risk of

harm or failure to perceive a substantial risk of harm when a reasonable person would have perceived it (commonly

represented by the terms “recklessness” and “negligence,” respectively).

A class of “public welfare” or “regulatory” offenses may actually require no mens rea for their commission at all. For this

class of offenses, rather than applying the presumption in favor of scienter, statutory silence is treated as imposing “strict

criminal liability” in the sense that one need not have at least knowledge of the facts that make one’s conduct illegal.

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.

In the past, Congress has considered legislation that would have established default mens rea requirements and application

rules in the absence of clear standards in the offense text, and at least one bill (S. 739) has been introduced to this effect in the

117th Congress. Among other things, such legislation would impose standards of either knowledge or willfulness on many

offense elements and would require that mens rea terms provided in the text should ordinarily apply to each offense element,

with exceptions. Proponents of such efforts argue that strict-liability offenses and offenses with weak mental-state

requirements fail to provide fair notice and represent part of a broader trend of federal over-criminalization. Opponents assert

that applying blanket mens rea requirements to existing offenses could permit corporate wrongdoers to evade prosecution and

produce unintended consequences. Ultimately, comprehensive mens rea legislation has not become law as of this writing.

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Mens Rea: An Overview of State-of-Mind Requirements for Federal Criminal Offenses

Contents

Introduction ..................................................................................................................................... 1

Background ..................................................................................................................................... 3

Model Penal Code Approach ........................................................................................................... 5

Federal Mens Rea Requirements ..................................................................................................... 9

Federal Mens Rea Interpretive Approach ................................................................................. 11

Whether Mens Rea is Required.......................................................................................... 11

Application of Mens Rea to Specific Elements ................................................................ 15

Meaning of Mens Rea Standards in Federal Statutes .............................................................. 18

Intentionally, Knowingly, and Willfully............................................................................ 19

Recklessly and Negligently............................................................................................... 25

Other Mens Rea Standards ................................................................................................ 29

Selected Additional Mens Rea Issues in Federal Law............................................................. 30

Inchoate Crimes ................................................................................................................ 31

Corporate Liability ............................................................................................................ 33

Defenses ............................................................................................................................ 34

Federal Mens Rea Reform and Considerations for Congress ........................................................ 36

117th Congress ........................................................................................................................ 37

114th and 115th Congresses .................................................................................................... 38

Considerations for Congress ................................................................................................... 40

Tables

Table 1. MPC Culpability Levels .................................................................................................... 7

Contacts

Author Information........................................................................................................................ 42

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Mens Rea: An Overview of State-of-Mind Requirements for Federal Criminal Offenses

Introduction

To say that the legal principle actus non facit reum nisi mens sit rea1 is longstanding 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

1 An alternative phrasing that is sometimes used is actus reus non facit reum nisi mens sit rea. Compare United States

v. Bates, 96 F.3d 964, 967 (7th Cir. 1996), with Craig A. Stern, The Heart of Mens Rea and the Insanity of

Psychopaths, 42 CAP. U. L. REV. 619, 627 n.58 (2014).

2 Matthew R. Ginther & Francis X. Shen, et al., Decoding Guilty Minds: How Jurors Attribute Knowledge and Guilt,

71 VAND. L. REV. 241, 245 n.10 (2018); see also Francis Bowes Sayre, Mens Rea, 45 HARV. L. REV. 974, 974 (1932)

(stating that the phrase has been used “[f]or hundreds of years . . . with unbroken cadence”).

3 Morissette v. United States, 342 U.S. 246, 250 (1952).

4 Id. at 250-51. This principle addresses broader notions of the purposes of criminal law and its effectiveness in

deterring, reforming, and/or punishing, i.e., what sorts of behaviors are justly proscribed and can reasonably be

expected to be curtailed by the threat of criminal penalties. See, e.g., id. (noting that the concept of a mental element in

criminal law “is almost as instinctive as the child’s familiar exculpatory ‘But I didn’t mean to,’ and has afforded the

rational basis for a . . . substitution of deterrence and reformation in place of retaliation and vengeance as the

motivation for public prosecution”); Stephen J. Morse, Inevitable Mens Rea, 27 HARV. J.L. & PUB. POL’Y 51, 61 (2003)

(“If the criminal law operates by guiding the conscious actions of persons capable of understanding the rules and

rationally applying them, it would be unfair and thus unjustified to punish and to inflict pain intentionally on those who

did not act intentionally or who were incapable of the minimum degree of rationality required for normatively

acceptable cooperative interaction.”).

5 Various terms are used in judicial opinions and legal scholarship to describe the mental component of a crime,

including mens rea, state of mind, mental state, and scienter. This report uses such terms interchangeably. As noted

below, the Model Penal Code treats the concept of a crime’s mental component under the rubric of “culpability.” See

infra notes 42-71 and accompanying text.

6 WAYNE R. LAFAVE, SUBSTANTIVE CRIMINAL LAW § 5.1 (3d ed. 2017); see Criminal Negligence, BLACK’S LAW

DICTIONARY (11th ed. 2019) (defining criminal negligence as, among other things, an “objectively assessed mental

state of an actor who should know” that there is a certain degree of risk in a prohibited action). However, criminal

negligence is not common in the context of federal criminal law. See 1A KEVIN F. O’MALLEY, JAY E. GRENIG, &

WILLIAM C. LEE, FEDERAL JURY PRACTICE & INSTRUCTIONS § 17:01 (6th ed. 2006) (indicating that concepts of

recklessness, negligence, and strict liability have “little relevance in federal criminal law”); Elonis v. United States, 135

S. Ct. 2001, 2011 (2015) (“[W]e have long been reluctant to infer that a negligence standard was intended in criminal

statutes.” (citation and internal quotation marks omitted)); but see, e.g., 33 U.S.C. § 1319(c) (establishing criminal

penalties for negligent violations of certain pollutant discharge limitations, among other things).

7 E.g., Robert Batey, Judicial Exploitation of Mens Rea Confusion, at Common Law and Under the Model Penal Code,

18 GA. ST. L. REV. 341, 341-42 (2001) (referring to “infinite shades of meaning” among common-law mens rea

standards and “important fundamental mens rea questions that still have no clear answers”); United States v. Bailey,

444 U.S. 394, 403 (1980) (“Few areas of criminal law pose more difficulty than the proper definition of the mens rea

required for any particular crime.”); United States v. Marshall, 753 F.3d 341, 345 (1st Cir. 2014) (“The statutory term

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Mens Rea: An Overview of State-of-Mind Requirements for Federal Criminal Offenses

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

‘willfully’ is a chameleon, what the Supreme Court has called ‘a word of many meanings whose construction is often

dependent on the context in which it appears.’” (citation omitted)).

8 See infra § “Whether Mens Rea is Required”; Morissette, 342 U.S. at 250, 252-255 (stating that the requirement of a

“mental element” for commission of a crime is “no provincial or transient notion” but recognizing offenses “of another

character” which require no such element and “consist only of forbidden acts or omissions”).

9 See David M. Treiman, Recklessness and the Model Penal Code, 9 AM. J. CRIM. L. 281, 284-85 (1981) (describing

MPC as “model for” reforming common-law mens rea principles reflected in statutes of the time).

10 See id.

11 Id. (indicating that as of 1981, nearly two-thirds of states had revised their criminal codes based on the MPC, and

many revisions included the MPC’s section on culpability); see Paul H. Robinson & Markus D. Dubber, The American

Model Penal Code: A Brief Overview, 10 NEW CRIM. L. REV. 319, 326 (2007) (identifying “thirty-four [state]

enactments [that] were influenced in some part by the Model Penal Code”).

12 E.g., Bailey, 444 U.S. at 406 (looking to “[p]rinciples derived from common law as well as precepts suggested by

the” MPC to discern level of culpability); Voisine v. United States, 136 S. Ct. 2272, 2278 (2016) (citing MPC

definition of “reckless” as “the dominant formulation”).

13 Geraldine Szott Moohr, Playing with the Rules: An Effort to Strengthen the Mens Rea Standards of Federal Criminal

Laws, 7 J. L. ECON. & POL’Y 685, 692 (2011) (“The United States Code does not define mens rea terms or provide

interpretive guidelines. Instead, each federal criminal law specifies its own mens rea element, making it possible for

legislators to select from a wealth of common law terms.”).

14 For more information on statutory interpretation as a general matter, see CRS Report R45153, Statutory

Interpretation: Theories, Tools, and Trends, by Valerie C. Brannon.

15 E.g., United States v. X-Citement Video, Inc., 513 U.S. 64, 72 (1994) (acknowledging a “presumption in favor of a

scienter requirement” that “should apply to each of the statutory elements that criminalize otherwise innocent

conduct”).

16 E.g., Mens Rea Reform Act of 2018, S. 3118, 115th Cong. (2018); Criminal Code Reform Act of 1977, S. 1437, 95th

Cong. ch. 3 (as passed by Senate, Jan. 30, 1978). For further discussion, see infra notes Error! Bookmark not d

efined.-Error! Bookmark not defined. and accompanying text.

17 This report limits its focus to federal mens rea requirements for purposes of criminal liability and thus largely does

not address mental-state issues that may arise at sentencing or under the U.S. Sentencing Guidelines. See, e.g., United

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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-ofmind 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

States v. Prophet, __F.3d__, No. 18-3776, 2021 WL 800384, at *2 (3d Cir. Mar. 3, 2021) (noting circuit split regarding

whether earlier version of Guideline enhancement required finding of mens rea).

18 Because, as already described, federal mens rea standards are statute-specific and non-uniform, it would be

impossible to comprehensively address the state-of-mind requirements for federal crimes in a general way. Thus, this

report seeks only to exemplify the variation in federal criminal law by exploring the requirements of a few

representative statutes.

19 LAFAVE, supra note 6, § 5.1.

20 See Martin R. Gardner, The Mens Rea Enigma: Observations on the Role of Motive in the Criminal Law Past and

Present, 1993 UTAH L. REV. 635, 642 (1993) (tracing origins of a mental element in crime to “the earliest known legal

systems” but noting that “systematic mens rea requirements” did not exist in Anglo-Saxon law “until at least the

thirteenth century”).

21 Id. at 654-67.

22 Id. at 667. Motive is often now recognized to be analytically distinct from mens rea. United States v. Safehouse, 985

F.3d 225, 238 (3d Cir. 2021) (“[M]otive is distinct from mens rea. A defendant can be guilty even if he has the best of

motives.”); Gardner, supra note 20, at 694 (“The modern practice . . . largely abandons the evil motive tradition at the

offense definition level by defining the mens rea required for each crime descriptively in terms of particular states of

mind.”). The relationship between the two can still sometimes creates conceptual difficulty in particular contexts,

however. See, e.g., United States v. Ali, 870 F. Supp. 2d 10, 20 (D.D.C. 2012) (“Court decisions, treatises, and law

reviews are rife with debates about the relationship between specific intent and motive, and the relevance (if any) of the

latter in a criminal case.”). Motive may also be an express element of particular crimes, such as hate crimes, e.g., 18

U.S.C. § 249(a) (prohibiting certain acts “because of the actual or perceived race, color, religion, or national origin of

any person,” among other things), and, depending on one’s definition, may also be considered a component of certain

defenses to criminal liability. See, e.g., Rosemond v. United States, 572 U.S. 65, 89 (2014) (Alito, J., concurring in part

and dissenting in part) (“Unsurprisingly, our cases have recognized that a lawful motive (such as necessity, duress, or

self-defense) is consistent with the mens rea necessary to satisfy a requirement of intent.”); Gardner, supra note 20, at

694-95 (explaining that the law “affords excuses in certain situations, even though offenders act with the specific state

of mind required for the crime but either lack, or lack the capacity to form, the evil motive essential for moral blame”).

23 Morissette v. United States, 342 U.S. 246, 252 (1952).

24 Id. at 252 (“The unanimity with which [courts] have adhered to the central thought that wrongdoing must be

conscious to be criminal is emphasized by the variety, disparity and confusion of their definitions of the requisite but

elusive mental element.”); Treiman, supra note 9, at 284 (“Before 1960, most states had criminal codes that were little

more than statutory versions of the common law . . . . Each crime was defined in virtual isolation from others and

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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

consequently, the meaning of terms would vary from crime to crime, with no attempt at consistent definition . . . .”).

25 United States v. Bailey, 444 U.S. 394, 403 (1980); Batey, supra note 7, at 343. As discussed in more detail infra, a

third category of so-called regulatory or strict-liability offenses requires no culpable mental state at all. See Morissette,

342 U.S. at 252-53 (noting offenses “with very different antecedents and origins” that “depend on no mental element

but consist only of forbidden acts or omissions”).

26 Eric A. Johnson, Understanding General and Specific Intent: Eight Things I Know for Sure, 13 OHIO ST. J. CRIM. L.

521, 525, 527 (2016); see also United States v. Lamott, 831 F.3d 1153, 1156 (9th Cir. 2016) (“In a crime requiring

‘specific intent,’ the government must prove that the defendant subjectively intended or desired the proscribed act or

result.”).

27 Johnson, supra note 26, at 525.

28 Lamott, 831 F.3d at 1156. Defining general intent solely in terms of volition is of dubious usefulness, as any crime

proscribing an affirmative act requires that the act be voluntary. See LAFAVE, supra note 6, § 6.1(c) (“At all events, it is

clear that criminal liability requires that the activity in question be voluntary.”).

29 United States v. Delis, 558 F.3d 177, 180 (2d Cir. 2009).

30 Id.

31 United States v. Bailey, 444 U.S. 394, 403 (1980) (quoting WAYNE R. LAFAVE & AUSTIN W. SCOTT, JR., HANDBOOK

ON CRIMINAL LAW 201-02 (1972)).

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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

32 Johnson, supra note 26, at 522-23.

33 Francis X. Shen & Morris B. Hoffman, et al., Sorting Guilty Minds, 86 N.Y.U. L. REV. 1306, 1310 (2011).

34 Id. at 1311.

35 See Johnson, supra note 26, at 532-36 (noting court disagreement and arguing that such crimes should be considered

general intent crimes).

36 Treiman, supra note 9, at 284.

37 Batey, supra note 7, at 341.

38 Morissette v. United States, 342 U.S. 246, 252 (1952).

39 Batey, supra note 7, at 401; see also Ronald L. Gainer, The Culpability Provisions of the Model Penal Code, 19

RUTGERS L.J. 575, 579 (1988) (explaining that the MPC drafters “were required to resolve an approach to culpability”

and “appeared to recognize that the fundamental need was clarity”).

40 MODEL PENAL CODE § 2.02 (1985).

41 See, e.g., Gainer, supra note 39, at 579 (describing MPC approach as “the now classic approach to culpability that

few of us could imagine doing without”); Paul H. Robinson, A Brief History of Distinctions in Criminal Culpability, 31

HASTINGS L.J. 815, 816 & n.7 (1980) (recognizing that around seventy percent of states undertaking code revisions

adopted a mental-state system “essentially identical” to the MPC, and even those that did not were “significantly

influenced” by it).

42 Robinson & Dubber, supra note 11, at 323; see also Sanford H. Kadish, Fifty Years of Criminal Law: An

Opinionated Review, 87 CAL. L. REV. 943, 947-48 (1999). The MPC was reissued with Commentaries in 1980 and

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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:

1985.

43 See supra notes 11-12 and accompanying text; Paul H. Robinson, The Rise and Fall and Resurrection of American

Criminal Codes, 53 LOUISVILLE L. REV. 173, 173 (2015).

44 Robinson, Brief History, supra note 41, at 815.

45 Id. at 816.

46

MODEL PENAL CODE §§ 2.02(2)(a)-(d), 2.05 (1985).

47 See generally id. § 2.02. The MPC defines the term “element of an offense” as such conduct, circumstance, or result

of conduct as “is included in the description of the forbidden conduct in the definition of the offense,” establishes the

requisite culpability, negates an excuse, justification, or a statute of limitations defense, or establishes jurisdiction or

venue. Id. § 1.13(9).

48 Paul H. Robinson, Reforming the Federal Criminal Code: A Top Ten List, 1 BUFF. CRIM. L. REV. 225, 235 (1997).

49 Id.

50 MODEL PENAL CODE § 2.02 (1985); e.g., id. § 2.02(2)(a) (“Purposely. A person acts purposely with respect to a

material element when (i) if the element involves the nature of his conduct or a result thereof, it is his conscious object

to engage in conduct of that nature or to cause such a result; and (ii) if the element involves the attendant

circumstances, he is aware of the existence of such circumstances or he believes or hopes that they exist.”) (emphasis

added).

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Table 1. MPC Culpability Levels

Culpability Level

Conduct

Circumstance

Result

Purposely

Conscious object to

engage in conduct of

that nature

Aware of the

existence of such

circumstances or

believes or hopes that

they exist

Conscious object to

cause such a result51

Knowingly

Aware that conduct is

of that nature

Aware of at least a

high probability that

such circumstances

exist, unless actor

actually believes they

do not exist52

Aware that it is

practically certain

that conduct will

cause such a result

Recklessly

None53

Consciously

disregards a

substantial and

unjustifiable risk that

the material element

exists

Consciously

disregards a

substantial and

unjustifiable risk that

the material element

will result from

conduct54

Negligently

None

Should be aware of a

substantial and

unjustifiable risk that

the material element

exists

Should be aware of a

substantial and

unjustifiable risk that

the material element

will result from

conduct55

Strict Liability

None

None

None

51 A separate provision establishes that a “conditional” purpose satisfies the requirement of purpose “unless the

condition negatives the harm or evil sought to be prevented by the law defining the offense.” Id. § 2.02(6).This

provision encompasses a situation where, for instance, an actor might be guilty of larceny (which requires a purpose to

deprive the owner permanently of property) if the actor takes property intending to keep it unless the actor wins the

lottery. In this situation, though the purpose is conditional, the condition does not “negative[] the harm or evil sought to

be prevented,” but if the actor takes the property intending to keep it only if it turns out to actually be his, the harm or

evil arguably would be negated. See LAFAVE, supra note 6, § 5.2(d).

52 This definition, which is actually a product of two separate provisions of Section 2.02, encompasses a formulation of

the common-law “willful blindness” doctrine, under which “persons who know enough to blind themselves to direct

proof of critical facts in effect have actual knowledge of those facts” for mens rea purposes. Global-Tech Appliances,

Inc. v. SEB S.A., 563 U.S. 754, 766 (2011).

53 The MPC does not expressly define recklessness or negligence with respect to conduct, though commentators have

different perspectives on the significance of the omission. Some commentators have posited that the drafters may have

thought that recklessness or negligence as to conduct is not likely to arise, while others have suggested that the

minimum culpability that applies with respect to conduct is knowledge. For further discussion of this issue, see Paul H.

Robinson & Jane A. Grall, Elements Analysis in Defining Criminal Liability: The Model Penal Code and Beyond, 35

STAN. L. REV. 681, 710-12 (1983).

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Source: American Law Institute, Model Penal Code, Section 2.02.

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

54 For recklessness in general, “[t]he risk must be of such a nature and degree that, considering the nature and purpose

of the actor's conduct and the circumstances known to him, its disregard involves a gross deviation from the standard of

conduct that a law-abiding person would observe in the actor's situation.” MODEL PENAL CODE § 2.02(2)(c) (1985).

55 For negligence in general, “[t]he risk must be of such a nature and degree that the actor's failure to perceive it,

considering the nature and purpose of his conduct and the circumstances known to him, involves a gross deviation from

the standard of care that a reasonable person would observe in the actor's situation.” Id. § 2.02(2)(d).

56 Id. § 2.02.

57 See, e.g., Robinson & Grall, supra note 53, at 692-93 (noting that Section 2.02 “clarifies mens rea analysis” by,

among other things, “narrow[ing]” the “eighty or so culpability terms” that existed previously).

58 Id. at 688.

59 E.g., MODEL PENAL CODE §§ 2.02-.06 (1985).

60 The MPC defines a “material element” as an element that does not relate to basic matters such as the statute of

limitations, jurisdiction, venue, or other matters unconnected with “the harm or evil . . . sought to be prevented by the

law defining the offense” or a justification or excuse for the proscribed conduct. Id. § 1.13(10).

61 Id. § 2.02(3). An explanatory note states that “[t]here is a rough correspondence between this provision and the

common law requirement of ‘general intent.’” Id. § 2.02 explanatory note. The drafters, by omitting “negligence” and

referencing general intent, seemed to indicate that crimes without an explicit mens rea requirement would maintain a

common-law conception requiring at least some conscious awareness of relevant information, as distinct from mere

accident. See supra notes 28-35 and accompanying text.

62 Id. § 2.02(4).

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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

63 See Gardner, supra note 20, at 683. The house pigeon example discussed in the Gardner article stems from a 19th

century English law addressed in the common-law case of Cotterill v. Penn. Id. at 679.

64 E.g., MODEL PENAL CODE § 2.04 (1985) (recognizing that ignorance or mistake is a defense if it negates the mental

state required for a material element of the offense, with exceptions).

65 See infra § “Selected Additional Mens Rea Issues in Federal Law.”

66 E.g., Robinson & Grall, supra note 53, at 706-07 (“A major defect of the Model Penal Code is its failure to define

adequately the three kinds of objective elements of an offense,” which is “essential for proper application of the defined

culpability terms.”); Kenneth W. Simons, Should the Model Penal Code’s Mens Rea Provisions Be Amended?, 1 OHIO

ST. J. CRIM. L. 179, 182-84 (2003) (diagnosing various problems).

67 Kenneth W. Simons, Rethinking Mental States, 72 B.U. L. REV. 463, 474 (1992).

68 Robinson & Grall, supra note 53, at 715.

69 Simons, Model Penal Code’s Mens Rea Provisions, supra note 66, at 180.

70 See Shen & Hoffman, supra note 33, at 1318 (“Whether in actual legislation, common law, or simply norms accepted

by lawyers and judges, the MPC has become ‘a standard part of the furniture of the criminal law.’” (citation omitted));

Batey, supra note 7, at 341 (indicating that as of 2001, “a substantial minority” of U.S. jurisdictions used the culpability

structure reflected in Section 2.02 of the MPC).

71 United States v. U.S. Gypsum Co., 438 U.S. 422, 444 (1978).

72 Pub. L. No. 89-801. 80 Stat. 1516 (1966).

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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

73 See 1 NAT’L COMM’N ON REFORM OF FED. CRIM. L., WORKING PAPERS 118-20 (1970).

74 Id. at 119.

75 Id.

76 Id. at 119-20.

77 Id.

78 Id. at 120-21.

79 See NAT’L COMM’N ON REFORM OF FED. CRIM. L., FINAL REPORT: PROPOSED NEW FEDERAL CRIMINAL CODE 27-29

(1971), https://www.ndcourts.gov/Media/Default/Legal%20Resources/legal-research/criminal-code/FinalReport.pdf.

80 E.g., Criminal Code Reform Act of 1977, S. 1437, 95th Cong. ch. 3 (as passed by Senate, Jan. 30, 1978).

81 E.g., Mens Rea Reform Act of 2018, S. 3118, 115th Cong. (2018).

82 Moohr, supra note 13, at 692.

83 Id. at 693.

84 John G. Malcolm, Morally Innocent, Legally Guilty: The Case for Mens Rea Reform, 18 FEDERALIST SOC’Y REV. 40,

41 (2017). This number does not include federal regulations that implicate criminal penalties, which may number in the

thousands as well. Id.

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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 mentalstate 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

85 Staples v. United States, 511 U.S. 600, 605 (1994) (citation, internal alteration, and internal quotation marks

omitted).

86 E.g., id. at 605-08 (addressing existence of knowledge requirement in statute with no explicit mens rea and

application of that requirement to different elements of offense).

87 Eric A. Johnson, Rethinking the Presumption of Mens Rea, 47 WAKE FOREST L. REV. 769, 770 (2012); see United

States v. Figueroa, 165 F.3d 111, 119 (2d Cir. 1998) (Sotomayor, J.) (referencing “principles of construction

underlying the criminal law” as “signposts to congressional intent”).

88

Staples, 511 U.S. at 605.

89 See Figueroa, 165 F.3d at 114 (“By using the word ‘knowingly,’ Congress chose to include some knowledge

requirement for a conviction under [the statute].”).

90 “Strict-liability crime” is defined as one “for which the action alone is enough to warrant a conviction, with no need

to prove a mental state; specif., a crime that does not require a mens rea element, such as traffic offenses and illegal

sales of intoxicating liquor.” Strict-Liability Crime, BLACK’S LAW DICTIONARY (11th ed. 2019). Strict liability may

apply to only one or some of the elements of an offense. E.g., Staples, 511 U.S. at 609 (addressing statute imposing

strict liability as to unregistered nature of firearm but requiring knowledge of features of firearm making it subject to

regulation).

91 Rehaif v. United States, 139 S. Ct. 2191, 2195 (2019).

92 Id. (citation, internal alteration, and internal quotation marks omitted).

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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

93 Staples, 511 U.S. at 606.

94 Morissette v. United States, 342 U.S. 246, 263 (1952).

95

Id.

96 18 U.S.C. § 641.

97 Morissette, 342 U.S. at 252, 254 n.14. The Morissette Court rooted its decision in the principle that “where Congress

borrows terms of art in which are accumulated the legal tradition and meaning of centuries of practice, it presumably

knows and adopts the cluster of ideas that were attached to each borrowed word in the body of learning from which it

was taken and the meaning its use will convey to the judicial mind unless otherwise instructed.” Id. at 263. In

accordance with this principle, the Court recognized that “[s]tealing, larceny, and its variants and equivalents” were

well-known at common law, and judicial precedent “consistently retained the requirement of intent in larceny-type

offenses.” Id. at 261. The Court in later decisions has appeared to recognize the applicability of the presumption even to

statutes lacking direct common-law antecedents, however. E.g., Rehaif v. United States, 139 S. Ct. 2191, 2195 (2019)

(acknowledging that presumption is “traceable to the common law” but referring to the presumption as applicable

generally to “criminal statutes”).

98 United States v. U.S. Gypsum Co., 438 U.S. 422, 437 (1978).

99 Id. (quoting Rewis v. United States, 401 U.S. 808, 812 (1971)).

100 Carter v. United States, 530 U.S. 255, 269 (2000) (quoting United States v. X-Citement Video, Inc., 513 U.S. 64, 72

(1994)). As explained in more detail infra, this formulation also speaks to the question of which elements of a statutory

offense bear a mens rea requirement.

101 See Carter, 530 U.S. at 268 (concluding that presumption in favor of scienter required proof “of general intent—

that is, that the defendant possessed knowledge with respect to the actus reus of the crime,” but caveating that “some

situations may call for implying a specific intent requirement into statutory text”); Elonis v. United States, 135 S. Ct.

2001, 2012 (2015) (concluding that statute proscribing transmission of threatening communication required purpose to

threaten or knowledge of threatening nature of communication, but declining to address whether recklessness as to

threat would be sufficient); John Shepard Wiley Jr., Not Guilty by Reason of Blamelessness: Culpability in Federal

Criminal Interpretation, 85 VA. L. REV. 1021, 1112 (1999) (“[W]hen Congress has omitted all culpability language, . . .

[t]he Court apparently has adopted the ‘knowledge’ standard as the default[.]”).

102 26 U.S.C. § 5861(d).

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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 strictliability 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

103 511 U.S. 600, 619 (1994).

104 Id. at 605, 614-15.

105 Id. at 606-07.

106 Id. at 607.

107 Morissette v. United States, 342 U.S. 246, 254, 256 (1952) (recognizing criminal regulatory offenses “which

heighten the duties of those in control of particular industries, trades, properties or activities that affect public health,

safety or welfare” and noting that “penalties [for such offenses] commonly are relatively small, and conviction does no

grave damage to an offender’s reputation”).

108 258 U.S. 250, 251 (1922).

109 Id. at 251, 253-54.

110 Id. at 252.

111 Id. at 254.

112 Staples v. United States, 511 U.S. 600, 607 (1994); see also United States v. U.S. Gypsum Co., 438 U.S. 422, 43738 (1978) (“[T]he limited circumstances in which Congress has created and this Court has recognized such offenses . . .

attest to their generally disfavored status.”); Morissette, 342 U.S. at 251 (referencing “universal and persistent” notion

that crime requires intention).

113 See, e.g., Staples, 511 U.S. at 607; Morissette, 342 U.S. at 255-56; United States v. Dotterweich, 320 U.S. 277, 28182 (1943); Balint, 258 U.S. at 254.

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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 socalled “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

114 Leonid Traps, “Knowingly” Ignorant: Mens Rea Distribution in Federal Criminal Law After Flores-Figueroa, 112

COLUM. L. REV. 628, 633 (2012).

115 Staples, 511 U.S. at 607.

116 United States v. Figueroa, 165 F.3d 111, 116 (2d Cir. 1998) (Sotomayor, J.).

117 Staples, 511 U.S. at 607 n.3.

118 18 U.S.C. § 2252(a).

119 513 U.S. 64, 78 (1994).

120 CRS In Focus IF11072, The First Amendment: Categories of Speech, by Victoria L. Killion.

121 Id.

122 513 U.S. at 78; see United States v. Class, 930 F.3d 460, 468-70 (D.C. Cir. 2019) (noting that due-process

vagueness analysis is “more searching” where law imposes criminal penalties, threatens to inhibit exercise of a

constitutional right, and lacks a scienter requirement, but upholding statute prohibiting firearm possession on Capitol

grounds despite lack of requirement that defendant know he is on Capitol grounds); but cf. United States v. Wilson, 565

F.3d 1059, 1068 (8th Cir. 2009) (noting that “the First Amendment calculus is different depending on the proximity of

the defendant to the victim” and concluding that criminal prohibition on production of child pornography is “not

entitled to any mens rea safeguards”).

123 United States v. Enochs, 857 F.2d 491, 494 n.2 (8th Cir. 1988); see also United States v. Wulff, 758 F.2d 1121,

1125 (6th Cir. 1985) (indicating that mens rea may only constitutionally be eliminated “where (1) the penalty is

relatively small, and (2) where conviction does not gravely besmirch,” and concluding that felony provision of

Migratory Bird Treaty Act “d[id] not meet these criteria”); cf. United States v. DeCoster, 828 F.3d 626, 633 (8th Cir.

2016) (“The elimination of a mens rea requirement does not violate the Due Process Clause for a public welfare

offense where the penalty is ‘relatively small,’ the conviction does not gravely damage the defendant's reputation, and

congressional intent supports the imposition of the penalty.”).

124 Wulff, 758 F.2d at 1125.

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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.

125 Lambert v. California, 355 U.S. 225, 228-29 (1957). The provision in Lambert made it unlawful for any person

convicted of a felony “to be or remain in Los Angeles for a period of more than five days without registering” with the

Chief of Police. Id. at 226. In striking down the ordinance, the Court reasoned that notice is “[e]ngrained in [the]

concept of due process.” Id. at 228.

126 See Balint, 258 U.S. at 252 (“It has been objected that punishment of a person for an act in violation of law when

ignorant of the facts making it so, is an absence of due process of law. But that objection is considered and overruled . .

. .”); U.S. Gypsum Company, 438 U.S. at 437 (stating that “strict-liability offenses are not unknown to the criminal law

and do not invariably offend constitutional requirements”). The Court has also noted the muted impact of Lambert,

stating that its “application has been limited” and signaling some agreement with the proposition that it “stands as an

isolated deviation from the strong current of precedents[.]” Texaco, Inc. v. Short, 454 U.S. 516, 537 (1982) (citation

and internal quotation marks omitted).

127 United States v. Engler, 806 F.2d 425, 433 (3d Cir. 1986) (stating that bright-line rule regarding felonies “ignore[s]

a formidable line of cases imposing strict liability in felony cases without proof of scienter”); see also United States v.

Stepanets, __F.3d__, No. 19-1471, 2021 WL 748385, at *6 (1st Cir. Feb. 26, 2021) (“[Precedent] refutes the notion that

due process requires there to be a mens rea element in an offense as a categorical matter.”).

128

Engler, 806 F.2d at 434 (“The Supreme Court has indicated that the due process clause may set some limits on the

imposition of strict criminal liability, but it has not set forth definite guidelines as to what those limits might be.”)

129 See supra § “Model Penal Code Approach.”

130 See, e.g., Rehaif v. United States, 139 S. Ct. 2191, 2195-96 (2019) (assessing which elements of statutory crime

require knowledge).

131 18 U.S.C. § 1591(a). The statute also limits the “reckless disregard” standard for certain conduct and provides an

exception to the requirement of knowledge or reckless disregard of age where “the defendant had a reasonable

opportunity to observe the person” recruited. Id. §§ 1591(a), (c).

132 E.g., Rehaif, 139 S. Ct. at 2196 (referring to circumstance where mens rea term “introduces a long statutory phrase,

such that questions may reasonably arise about how far into the statute the modifier extends”); see supra notes 90-99

and accompanying text (discussing judicial development of presumption in favor of scienter).

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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

133 United States v. X-Citement Video, Inc., 513 U.S. 64, 72 (1994).

134 United States v. Figueroa, 165 F.3d 111, 116 (2d Cir. 1998) (Sotomayor, J.).

135

18 U.S.C. § 2242. The statute is jurisdictionally limited to the special maritime and territorial jurisdiction of the

United States and certain federal facilities. Id.

136 735 F.3d 754, 763 (8th Cir. 2013).

137 Id. at 761.

138 420 U.S. 671, 673 n.1 (1975) (quoting 18 U.S.C. § 111).

139 Id. at 685.

140 See Johnson, Rethinking the Presumption of Mens Rea, supra note 87, at 780 (“The academic commentary has been

broadly critical of this limitation on the mens rea presumption.”).

141 See supra note 62 and accompanying text.

142 556 U.S. 646, 647 (2009) (quoting 18 U.S.C. § 1028A(a)(1)).

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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

143 Id. at 652.

144 Traps, supra note 114, at 629; see also Darryl K. Brown, Federal Mens Rea Interpretation and the Limits of

Culpability’s Relevance, 75 L. & CONTEMP. PROBS. 109, 121 (2012) (“If [the Court’s] claim is taken as a canon of

construction, it should work much like the MPC’s provision that dictates a culpability term should apply to all material

elements.”).

145 Flores-Figueroa, 556 U.S. at 658 (Scalia, J., concurring); see also id. at 660 (Alito, J., concurring) (viewing as

“fair” a “general presumption” that a specified mens rea applies “to all the elements of the offense” but collecting

contextual instances where that presumption is rebutted).

146 United States v. Washington, 743 F.3d 938, 942 (4th Cir. 2014); see also United States v. Price, 921 F.3d 777, 786

(9th Cir. 2019) (“We have explicitly rejected the notion that the Court’s reading of ‘knowingly’ in Flores-Figueroa

compels the same reading in every criminal statute that uses the word ‘knowingly.’”); United States v. Cox, 577 F.3d

833, 838 (7th Cir. 2009) (indicating that Flores-Figueroa “did not establish a rule for all circumstances”); United States

v. Daniels, 653 F.3d 399, 410 (6th Cir. 2011) (“Flores-Figueroa does not compel a particular interpretation . . . .

Rather, the resolution of this issue depends on the relative weight given to text and context.”). Some courts have

expressly treated Flores-Figueroa as recognizing a presumption that a stated mens rea term, or at least a “knowingly”

term at the beginning of a sequence of statutory elements, applies to every subsequent element, which can be rebutted

“where the context or background circumstances of a statute lead to a different reading.” United States v. Bruguier, 735

F.3d 754, 761 (8th Cir. 2013) (citation and internal quotation marks omitted); United States v. Daniels, 685 F.3d 1237,

1248-49 (11th Cir. 2012) (“Although there is a general presumption that a knowing mens rea applies to every element

in a statute, cases concerned with the protection of minors are within a special context, where that presumption is

rebutted.”).

147 136 S. Ct. 1619, 1630 (2016).

148 139 S. Ct. 2191, 2195 (2019) (citing MODEL PENAL CODE § 2.02(4) (1985)).

149 Id. at 2197.

150 Id. at 2196 (noting that “jurisdictional elements do not describe the ‘evil Congress seeks to prevent’” (quoting

Torres, 136 S. Ct. at 1630)).

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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

151 Id. Additionally, relying on the notion that only the mens rea necessary to separate wrongful from otherwise

innocent conduct is required, courts have found no need to read a mens rea requirement into provisions that merely

enhance the sentence for conduct that is already criminally proscribed. E.g., Dean v. United States, 556 U.S. 568, 57576 (2009) (noting that “it is not unusual to punish individuals for the unintended consequences of their unlawful acts”

and concluding no mens rea applied to a “sentencing enhancement . . . account[ing] for the risk of harm resulting from

the manner in which the crime is carried out”); United States v. McDuffy, 890 F.3d 796, 801 (9th Cir. 2018) (“Thus,

the presumption in favor of scienter is lessened, if not altogether absent, when considering sentencing enhancement

provisions.”). Questions may arise as to when a provision in a statute constitutes an element of the offense versus an

enhancement provision. Cf. United States v. Burwell, 690 F.3d 500, 505, 508 (D.C. Cir. 2012) (calling “misguided” the

suggestion “that the label ‘element of the offense,’ as opposed to ‘sentencing factor,’ is determinative of the mens rea

requirement” and emphasizing that “certain offense elements do not require proof of an additional mens rea so long as

the offense as a whole carries a scienter requirement that separates innocent from criminal conduct”).

152 See supra notes 72-78; James A. Macleod, Belief States in Criminal Law, 68 OKLA. L. REV. 497, 511 (2016) (“The

federal criminal code employs a far greater array of mental state terms than does the MPC, and these terms are typically

left undefined in the statutes in which they are found.”).

153 See 1 WORKING PAPERS, supra note 73, at 119 (citing 18 U.S.C. §§ 201, 549, 1427, & 1506).

154 Macleod, supra note 152, at 511. Because mens rea, as “an ingredient of the crime charged,” is “a question of fact

which must be submitted to the jury,” Morissette v. United States, 342 U.S. 246, 274 (1952), judicial interpretations of

statutory mens rea requirements typically arise in the context of challenges to the trial court’s jury instructions defining

the mental-state element that must be proved. See, e.g., Liparota v. United States, 471 U.S. 419, 423 (1985) (involving

challenge to jury instructions based on district court’s refusal to instruct jury that specific intent was required).

155 Id. at 120.

156 O’MALLEY, GRENIG, & LEE, supra note 6, § 17:01.

157 MODEL CRIM. JURY INSTRUCTIONS ch. 5 (U.S. CT. APPEALS, 3D CIR. 2018) [hereinafter THIRD CIRCUIT JURY

INSTRUCTIONS], https://www.ca3.uscourts.gov/model-criminal-jury-table-contents-and-instructions (“Federal crimes

commonly include the mental states intentionally, knowingly, or willfully, and less commonly recklessly or

negligently.”).

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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

158 O’MALLEY, GRENIG, & LEE, supra note 6, § 17:01. A fourth term bearing similarity to the other three is

“maliciously,” which, in one formulation, denotes intent to do a prohibited act without justification, mitigation, or

excuse. E.g., United States v. Kelly, 676 F.3d 912, 918 (9th Cir. 2012); cf. United States v. Grady, 746 F.3d 846, 849

(7th Cir. 2014) (approving jury instruction defining “maliciously” as “intentionally or with deliberate disregard of the

likelihood that damage or injury would result” but omitting proposed addition of phrase “without just cause or reason”).

The concept of “malice” is used to define the requisite mental states for certain federal homicide crimes, which also

provide an example of one circumstance where the “mitigation or excuse” component of the above definition is

relevant—murder and voluntary manslaughter both require intent to kill or cause serious bodily injury (or at least

extreme recklessness as to such result), but voluntary manslaughter bears a mitigating element of “sudden quarrel or

heat of passion” that renders it “without malice.” United States v. Serawop, 410 F.3d 656, 664 (10th Cir. 2005); see

United States v. Delaney, 717 F.3d 553, 557 (7th Cir. 2013) (“This is puzzling, because ‘malice aforethought’ in the

statute means intent and so what does it mean to say that a person did something intentionally but without malice?”).

Malice can also bear a distinct meaning that incorporates notions of “evil purpose or motive” in at least one statute. See

United States v. Hassouneh, 199 F.3d 175, 181 (4th Cir. 2000) (“[T]he history surrounding the progression of the

Bomb Hoax Act confirms that Congress intended the term ‘acts willfully and maliciously’ to mean ‘acts with an evil

purpose or motive.’”).

159 Or at least a high enough degree of risk that the existence of the element is “virtually certain.” Shen & Hoffman,

supra note 33, at 1312 (describing “most recent major fault line in the law of intentionality” as distinguishing between

“desire-based intent” and “a new category of ‘recklessness-plus’” that is “grounded in the degree of risk the actor is

consciously undertaking”).

160 E.g., Bryan v. United States, 524 U.S. 184, 191 (1998) (“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.”).

161 See supra § “Background.”

162 United States v. U.S. Gypsum Co., 438 U.S. 422, 445 (1978) (quoting WAYNE R. LAFAVE & AUSTIN W. SCOTT, JR.,

CRIMINAL LAW 196 (1972)).

163 Id.

164 E.g., United States v. Tracy, 36 F.3d 187, 194 (1st Cir. 1994).

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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

165 United States v. Dyer, 589 F.3d 520, 528 (1st Cir. 2009); see also United States v. Tobin, 552 F.3d 29, 32-33 (1st

Cir. 2009) (“Although the word ‘intent’ can often mean with ‘knowledge’ that a particular result will follow, it

sometimes instead requires a ‘purpose’ to bring about a specific end.”). A specific intent requirement may even be

construed to encompass recklessness in some contexts. See United States v. McAnally, 666 F.2d 1116, 1119 (7th Cir.

1981) (“[T]raditionally in the criminal law an extreme form of recklessness has been treated as intentional . . . .”); but

see United States v. Adamson, 700 F.2d 953, 962 (5th Cir. 1983) (criticizing “loose references to recklessness” in

discussions of specific intent requirement of statute proscribing misapplication of bank funds). Recklessness as a mens

rea standard under federal law is discussed in more detail infra.

166 E.g., United States v. Veach, 455 F.3d 628, 632 (6th Cir. 2006) (acknowledging disagreement over whether statute

proscribing threatened assault of certain federal officials “with intent to . . . intimidate,” among other things, is specific

or general intent crime); United States v. Rodriguez, 416 F.3d 123, 126-27 (2d Cir. 2005) (disagreeing with Ninth

Circuit that immigration statute requires purpose to reenter U.S. illegally, rather than merely “knowingly and

intentionally” taking the action that constitutes an attempt to reenter). Depending on the statute, an intent requirement

may also be conditional, i.e., intent may be established if the defendant intends to take a proscribed action or produce a

proscribed result only “if necessary”; put differently, “a defendant may not negate a proscribed intent by requiring the

victim to comply with a condition the defendant has no right to impose.” Holloway v. United States, 526 U.S. 1, 11

(1999). This principle is consistent with the approach of the MPC. See MODEL PENAL CODE § 2.02(6) (1985) (“When a

particular purpose is an element of an offense, the element is established although such purpose is conditional, unless

the condition negatives the harm or evil sought to be prevented by the law defining the offense.”). Intent additionally

may be “transferred” where one has intent to harm a specific victim but a different victim is actually harmed instead.

See, e.g., United States v. Savage, 970 F.3d 217, 276 (3d Cir. 2020) (surveying application of doctrine under federal

law); cf. MODEL PENAL CODE § 2.03(2) (treating transferred intent as matter of causation).

167 E.g., United States v. Lynch, 881 F.3d 812, 815 (10th Cir. 2018) (“Where specific intent is not required, criminal

statutes are usually read to require ‘only that a defendant know the facts that make his conduct illegal.’” (citation

omitted)); United States v. Martinez, 49 F.3d 1398, 1401 (9th Cir. 1995), superseded by statute as recognized in United

States v. Randolph, 93 F.3d 656, 661 (9th Cir. 1996) (“[W]hen a statute does not contain any reference to intent,

general intent is ordinarily implied.”). As described supra, whether a particular federal statute establishes a general or

specific intent crime is ultimately a question of legislative intent that may depend on the text of the statute, how the

crime at issue was treated at common law, and legislative history, among other things. E.g., United States v. Lamott,

831 F.3d 1153, 1156-57 (9th Cir. 2016) (considering “[s]everal factors” as indicative of congressional intent to

establish general intent crime, including lack of use of phrase “with intent to,” common law precedent regarding assault

and battery, and legislative record surrounding passage of law).

168 O’MALLEY, GRENIG, & LEE, supra note 6, § 17:01 (quoting WAYNE R. LAFAVE, CRIMINAL LAW § 3.5 (4th ed.

2003)).

169 See supra § “Model Penal Code Approach.” Some federal courts may frame knowledge in terms of “belief” rather

than awareness, particularly in contexts such as sting operations where a circumstance element at issue may not

actually be present. E.g., United States v. Flores, 945 F.3d 687, 712 (2d Cir. 2019) (“[A]lthough knowledge is . . .

belief substantiated by veracity, in the context of a sting operation belief is tantamount to knowledge.” (citation and

internal quotation marks omitted)).

170 United States v. Bailey, 444 U.S. 394, 405 (1980); see also United States v. Ramamoorthy, 949 F.3d 955, 961 (6th

Cir. 2020) (“To commit a general-intent crime, a defendant must only intend to do the act that the law proscribes. To

commit a specific-intent crime, a defendant must do more than knowingly act in violation of the law. He must also act

with the purpose of violating the law.” (internal citations and quotation marks omitted)). One commentator has argued

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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

that the Supreme Court’s dicta in Bailey mistakenly treats the difference between general and specific intent as

“reducible to the difference between two mental states.” Johnson, Rethinking the Presumption of Mens Rea, supra note

87, at 790 n.119. As described above, at least one conception of the difference between general and specific intent is

that it delineates between the elements to which a given mental state attaches. See id. at 790-91; supra § “Background.”

171 United States v. Salinas, 763 F.3d 869, 880 (7th Cir. 2014). Ordinarily, “the term ‘knowingly’ merely requires proof

of knowledge of the facts that constitute the offense” and not knowledge of the law or unlawfulness. Bryan v. United

States, 524 U.S. 184, 193 (1998) (emphasis added). However, construction of particular statutes may lead to a different

result based on the analysis described supra, § “Application of Mens Rea to Specific Elements.” For instance, in

Liparota v. United States, the Court determined that a statute prohibiting knowing use of food stamps “in any manner

not authorized” by statute or regulation required a defendant to know “that his conduct was unauthorized or illegal.”

471 U.S. 419, 434 (1985).

172 See United States v. Sablan, 92 F.3d 865, 868 (9th Cir. 1996) (describing legislative history).

173 S. REP. NO. 99-432, at 6 (1986); see United States v. Drew, 259 F.R.D. 449, 459 (C.D. Cal. 2009) (quoting report

language in interpreting CFAA). The notion of intent as conscious object or purpose can also be significant for other

kinds of crimes like homicide, which is federally proscribed in jurisdictionally limited circumstances, and treason. See

Bailey, 444 U.S. at 405.

174 United States v. Jewell, 532 F.2d 697, 702 (9th Cir. 1976).

175 See Global-Tech Appliances, Inc. v. SEB S.A., 563 U.S. 754, 769 (2011) (mentioning that “the Courts of Appeals

. . . all appear to agree” on basic parameters of willful blindness doctrine). The concept, however, is “categorically

different from negligence or recklessness,” United States v. Heredia, 483 F.3d 913, 918 n.4 (9th Cir. 2007) (en banc),

which are discussed in more detail infra.

176 Id. One point of apparent disagreement concerns whether the defendant also must have the “motive in deliberately

failing to learn the truth . . . to give himself a defense in case he should be charged with the crime.” Heredia, 483 F.3d

at 919 (rejecting motive requirement); but see United States v. Davis, 901 F.3d 1030, 1034 (8th Cir. 2018) (stating that

willful blindness instruction “is proper if the evidence supports the inference that the defendant was aware of a high

probability of the existence of the fact in question and purposely contrived to avoid learning all of the facts in order to

have a defense in the event of a subsequent prosecution.” (internal alteration & quotation marks omitted)); see

generally Alexander F. Sarch, Willful Ignorance, Culpability, and the Criminal Law, 88 ST. JOHN’S L. REV. 1023

(2014) (describing disagreement).

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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

177 See Heredia, 483 F.3d at 917-18 (describing this situation).

178 United States v. Parker, 872 F.3d 1, 14 (1st Cir. 2017) (quoting Global-Tech, 563 U.S. at 766).

179 O’MALLEY, GRENIG, & LEE, supra note 6, § 17:01.

180 E.g., 18 U.S.C. § 924(a)(1)(D) (establishing criminal penalties for those who “willfully” violate certain firearm-

related requirements).

181 E.g., 18 U.S.C. § 1501 (prohibiting “knowingly and willfully” obstructing a federal process server, among other

things).

182 Bryan v. United States, 524 U.S. 184, 191 (1998) (quoting Spies v. United States, 317 U.S. 492, 497 (1943)).

183 United States v. Starnes, 583 F.3d 196, 210 (3d Cir. 2009) (quoting United States v. Ladish Malting Co., 135 F.3d

484, 487-88 (7th Cir. 1998)).

184 See 1 WORKING PAPERS, supra note 73, at 120.

185 Bryan, 524 U.S. at 191.

186 Dixon v. United States, 548 U.S. 1, 5 (2006). As noted above, construction of particular statutes may result in a

definition of “knowingly” that does include knowledge of unlawfulness to some degree, which may be thought of as

more akin to the typical formulation of a willfulness requirement. See supra note 171.

187 See Bryan, 524 U.S. at 195-96 (rejecting argument that willfulness requirement in firearm-related statute

necessitates knowledge of the law, as “knowledge that the conduct is unlawful is all that is required”); Screws v. United

States, 325 U.S. 91, 103, 106 (1945) (Reading willfulness requirement in 18 U.S.C. § 242 as calling for “specific intent

to deprive a person of a federal right made definite by decision or other rule of law” but indicating that defendant does

not need to be “thinking in constitutional terms”).

188 United States v. Starnes, 583 F.3d 196, 210 (3d Cir. 2009); see also United States v. Kosinski, 976 F.3d 135, 154

(2d Cir. 2020) (“As a general matter, a person who acts willfully need not be aware of the specific law that his conduct

may be violating. Rather, knowledge that the conduct is unlawful is all that is required.” (citation and internal quotation

marks omitted)); United States v. Hernandez, 859 F.3d 817, 823 (9th Cir. 2017) (“In this case, the government was

required to show that [the defendant] knew his transportation of firearms . . . was somehow unlawful, even if he did not

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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

know of the specific legal duty, or the particular law, that made it unlawful.”).

189 Starnes, 583 F.3d at 210.

190 Bryan, 524 U.S. at 191 n.12; see, e.g., United States v. Gonsalves, 435 F.3d 64, (1st Cir. 2006) (“Willfulness . . .

means nothing more in this context than that the defendant knew that his statement was false when he made it or . . .

consciously disregarded or averted his eyes from its likely falsity.”). This is the definition of willfulness embraced by

the MPC, which states that a willfulness requirement “is satisfied if a person acts knowingly with respect to the

material elements of the offense, unless a purpose to impose further requirements appears.” MODEL PENAL CODE

§ 2.02(8) (1985). Under federal law, in fact, a requirement of willfulness may even be construed to encompass

recklessness depending on the context. See United States v. Blankenship, 846 F.3d 663, 673 (4th Cir. 2017) (“In

interpreting a variety of criminal statutes, other Circuits have reached the same conclusion: . . . ‘reckless disregard’ still

can—and does—constitute criminal willfulness.”). Recklessness as a mens rea requirement in federal statutes is

discussed in more detail infra.

191 Bryan, 524 U.S. at 194.

192 Starnes, 583 F.3d at 211; see Ratzlaf v. United States, 510 U.S. 135, 149 (1994) (applying stringent formulation of

willfulness requirement to financial anti-structuring laws). In these circumstances, the inclusion of a willfulness

requirement may operate as an exception to the longstanding maxim that “ignorance of the law or a mistake of law is

no defense to criminal prosecution.” United States v. Marshall, 753 F.3d 341, 345 (1st Cir. 2014) (Souter, J.) (quotation

omitted). In other words, where a willfulness requirement necessitates proof that the defendant actually knew of the

legal provision that proscribed his conduct, ignorance of that law may constitute a defense to conviction because it

negates the requisite mens rea. A discussion of these and other defense issues that relate to mens rea can be found

infra, § “Selected Additional Mens Rea Issues in Federal Law.”

193 498 U.S. 192, 200, 202 (1991).

194 See Batey, supra note 7, at 367-71 (describing statute and court opinion construing it as “a particularly clear

example of the definitional possibilities inherent in general intent”).

195 18 U.S.C. § 81. In full, the statute provides:

Whoever, within the special maritime and territorial jurisdiction of the United States, willfully and

maliciously sets fire to or burns any building, structure or vessel, any machinery or building

materials or supplies, military or naval stores, munitions of war, or any structural aids or appliances

for navigation or shipping, or attempts or conspires to do such an act, shall be imprisoned for not

more than 25 years, fined the greater of the fine under this title or the cost of repairing or replacing

any property that is damaged or destroyed, or both.

If the building be a dwelling or if the life of any person be placed in jeopardy, he shall be fined

under this title or imprisoned for any term of years or for life, or both.

Id.

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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.

196 This report references a significant number of decisions by federal appellate courts of various regional circuits. For

purposes of brevity, references to a particular circuit in the body of this report (e.g., the Fifth Circuit) refer to the U.S.

Court of Appeals for that particular circuit.

197 890 F.2d 239, 239 (10th Cir. 1989).

198 Id.

199 Id. at 240.

200 Id. at 240-41.

201 Id. at 241.

202 136 F.3d 631, 635 (9th Cir. 1998).

203 Id. at 635.

204 Id. at 634, 636.

205 Id. at 637-38 (Fletcher, J., dissenting).

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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

206 See O’MALLEY, GRENIG, & LEE, supra note 6, § 17:01 (stating that concepts of recklessness and negligence “have

little relevance in federal criminal law”); THIRD CIRCUIT JURY INSTRUCTIONS, supra note 157, ch. 5, p. 36

(“‘Recklessly’ is not frequently used to define the state of mind requirement in federal criminal statutes.”).

207 E.g., 18 U.S.C. § 1591(a) (prohibiting, among other things, knowingly recruiting a person “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); 18

U.S.C. § 755 (establishing criminal penalties for one who “negligently suffers [a federal prisoner] to escape,” among

other things).

208 See, e.g., MODEL PENAL CODE §§ 2.02(2)(c)-(d) (1985).

209 E.g., id.; see supra note 6 and accompanying text; Godwin v. United States, 441 F. Supp. 3d 1243, 1257 n.9 (M.D.

Ala. 2020) (“The basic distinction between recklessness and negligence is that an actor 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.” (alteration, citation, and internal quotation marks omitted)).

210 Voisine v. United States, 136 S. Ct. 2272, 2278 (2016) (quoting MODEL PENAL CODE § 2.02(2)(c) (1985)).

211 MODEL PENAL CODE § 2.02(2)(c) (1985).

212 E.g., Farmer v. Brennan, 511 U.S. 825, 836-37 (1994); United States v. Fagatele, 944 F.3d 1230, 1239 (10th Cir.

2019); United States v. Rodriguez, 880 F.3d 1151, 1159-61 (9th Cir. 2018); Anderson v. Kingsley, 877 F.3d 539, 54345 (4th Cir. 2017); United States v. Mottweiler, 82 F.3d 769, 771 (7th Cir. 1996); Macleod, supra note 152, at 513 n.54

(“[T]he MPC recklessness ‘formulation is substantially the same as the formulations of recklessness in federal and state

criminal codes and judicial decisions.’” (quoting LARRY ALEXANDER & KIMBERLY KESSLER FERZAN, CRIME AND

CULPABILITY: A THEORY OF CRIMINAL LAW 35 (2009)).

213 Anderson, 877 F.3d at 545; see Farmer, 511 U.S. at 836-37 (“The criminal law . . . generally permits a finding of

recklessness only when a person disregards a risk of harm of which he is aware.”). The MPC further defines a

“substantial and unjustifiable” risk as a risk “of such a nature and degree that, considering the nature and purpose of the

actor's conduct and the circumstances known to him, its disregard involves a gross deviation from the standard of

conduct that a law-abiding person would observe in the actor's situation.” MODEL PENAL CODE § 2.02(2)(c) (1985).

Some federal courts may include this further definition in jury instructions as well, recognizing that although

recklessness requires subjective awareness, “the nature of the risk is measured by an objective standard.” United States

v. Rodriguez, 880 F.3d 1151, 1161 (9th Cir. 2018) (emphasis added); but cf. THIRD CIRCUIT JURY INSTRUCTIONS, supra

note 157, at ch. 5, pp. 35-36 (noting that although “the Third Circuit does not seem to have included this further

definition in its few cases discussing recklessly, the trial court could include it in an instruction on recklessly if it thinks

a further explanation is necessary”).

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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

214 Compare Rodriguez, 880 F.3d at 1160 (making clear that for purposes of statutory prohibition on transporting an

illegal alien for financial gain, defendant must not merely be aware of facts “from which the inference of the risk at

issue could be drawn” but must “actually draw the inference”), with United States v. Kendrick, 682 F.3d 974, 984 (11th

Cir. 2012) (stating that “reckless disregard” term in separate subsection of same statute “means to be aware of, but

consciously and carelessly ignore, facts and circumstances clearly indicating that” element exists); see also United

States v. Carson, 870 F.3d 584, 603 (7th Cir. 2017) (recognizing that “[o]ther courts to have considered the question

have concluded that the phrase ‘reckless disregard’ in [a] statute [proscribing sex-trafficking activities] requires only an

awareness of facts and circumstances that give rise to a risk of a . . . violation, not an awareness of the risk itself”).

215 See supra notes 168-169; United States v. Carr, 303 F.3d 539, 547 (4th Cir. 2002) (“From the definitions we see that

‘knowing’ and ‘reckless’ states of mind both require a subjective awareness of risk on the part of the actor. The

difference lies in the degree of the risk that the actor is aware of.”).

216 303 F.3d at 540 (addressing 18 U.S.C. § 844(i)).

217 Id. at 540-41. The state-of-mind distinction was relevant by virtue of the United States Sentencing Guidelines,

which in an application note encouraged a downward departure from the applicable sentencing range if “the defendant

did not cause the death intentionally or knowingly” but caused it through “recklessness or negligence.” Id. at 545-46

(citing U.S. SENT’G GUIDELINES MANUAL § 2A1.1 cmt. n.1 (U.S. SENT’G COMM’N 2001)). A separate application note

defined the term “reckless” in a similar fashion as the MPC. Id.

218 Id. at 544, 545.

219 Id.

220 Id. at 546-47.

221 Id. at 548 (citation and internal quotation marks omitted).

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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

222 United States v. Adamson, 700 F.2d 953, 962 (5th Cir. 1983) (emphasis omitted); see also United States v. Ladish

Malting Co., 135 F.3d 484, 488 (7th Cir. 1998) (“Criminal recklessness may be so close to actual knowledge that proof

of one suffices for proof of the other[.]”).

223 United States v. Krimsky, 230 F.3d 855, 859 (6th Cir. 2000) (quoting United States v. S & Vee Cartage Co., Inc.,

704 F.2d 914, 919 (6th Cir.1983)).

224 See supra note 190.

225 See LAFAVE, supra note 6, § 5.4(a) (indicating that negligence “will usually do for tort liability”).

226 See supra note 157 and accompanying text; William S. Laufer, Culpability and the Sentencing of Corporations, 71

NEB. L. REV. 1049, 1072 (1992) (“referencing “near complete absence of negligence” in Title 18 of U.S. Code).

227 LAFAVE, supra note 6, § 5.4(a).

228 United States v. Zats, 298 F.3d 182, 189 (3d Cir. 2002) (quoting MODEL PENAL CODE § 2.02(2)(d) (1985)).

229 Godwin v. United States, 441 F. Supp. 3d 1243, 1257 n.9 (M.D. Ala. 2020) (citation and internal quotation marks

omitted).

230 See LAFAVE, supra note 6, § 5.4(a)(2) (“All that negligence requires is that [a person] ought to have been aware of

[the risk] (i.e., that a reasonable man would have been aware of it).”).

231 MODEL PENAL CODE § 2.02(2)(d) (1985).

232 United States v. Pruett, 681 F.3d 232, 241 (5th Cir. 2012). The MPC and Pruett formulations of ordinary and socalled gross negligence are far from the only ones—as one commentator has noted, “[t]raditional criminal law doctrine

. . . does not employ or emphasize any single conception of negligence” but rather “contains a variety of doctrines that

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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

could be broadly classified as involving negligence[.]” Kenneth W. Simons, Dimensions of Negligence in Criminal and

Tort Law, 3 THEORETICAL INQUIRIES L. 283, 288 n.7 (2002).

233 Brigid Harrington, A Proposed Narrowing of the Clean Water Act’s Criminal Negligence Provisions: It’s Only

Human?, 32 B.C. ENV’T AFFS. L. REV. 643, 657 (2005); see Leslie Yalof Garfield, A More Principled Approach to

Criminalizing Negligence: A Prescription for the Legislature, 65 TENN. L. REV. 875, 910-11 (1998) (identifying a

“prevailing view that punishing ordinary negligent behavior generally should be avoided” as unjust and ineffective).

Sometimes the argument takes on a constitutional dimension. But see United States v. Hanousek, 176 F.3d 1116, 1122

(9th Cir. 1999) (rejecting argument that ordinary negligence standard in Clean Water Act violates due process).

234 Brook B. Andrews, Mens Rea in the CWA, S.C. LAW., July 2016, at 21, 23.

235 See Pruett, 681 F.3d at 243 (agreeing with Ninth and Tenth Circuits that ordinary negligence is sufficient for

misdemeanor Clean Water Act provision); United States v. Alvarez, 809 F. App’x 562, 567-68 (11th Cir. 2020) (per

curiam) (recognizing that plain language of Seaman’s Manslaughter Statute “criminalizes simple negligence”).

236 E.g., 42 U.S.C. § 7413(c)(4) (applying to one who “negligently places another person in imminent danger of death

or serious bodily injury”).

237 18 U.S.C. § 1112(a). Involuntary manslaughter may also occur through “the commission of an unlawful act not

amounting to a felony” or in the commission “in an unlawful manner” of a lawful act which might produce death. Id.

The offense is limited to conduct occurring within the special maritime and territorial jurisdiction of the United States.

Id. § 1112(b).

238 See United States v. Bolman, 956 F.3d 583, 586 (8th Cir. 2020) (defining gross negligence for purposes of

involuntary manslaughter as “wanton or reckless disregard for human life” with knowledge that the defendant’s

“conduct was a threat to the lives of others or having knowledge of such circumstances as could reasonably have

enabled him to foresee the peril to which his act might subject others”); United States v. Pineda-Doval, 614 F.3d 1019,

1038-39 (9th Cir. 2010) (similar).

239 29 U.S.C. § 666(e).

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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

240 135 F.3d 484, 486-87 (7th Cir. 1998). The employer contested “the requirement that it act ‘knowingly’ with respect

to the facts—that is, that the firm be aware” of the hazardous condition. Id. at 487.

241 Id. at 487.

242 Id. at 487-88.

243 Id. at 488.

244 Id.

245 Id.

246 Id.

247 See supra notes 152-154 and accompanying text.

248 E.g., 49 U.S.C. § 5124(b) (defining “knowingly” for purposes of criminal violations of restrictions on transportation

of hazardous material as “actual knowledge of the facts giving rise to the violation” or that “a reasonable person acting

in the circumstances and exercising reasonable care would have that knowledge”).

249 See 18 U.S.C. § 794(a) (proscribing delivery of defense information to foreign government or actor “with intent or

reason to believe that it is to be used to the injury of the United States or to the advantage of a foreign nation”); id. §

1521 (proscribing filing false lien against federal officer or employee “knowing or having reason to know” of falsity);

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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.

21 U.S.C. § 841(c)(2) (proscribing possession or distribution of listed chemicals “knowing, or having reasonable cause

to believe,” they will be used to manufacture controlled substance).

250 United States v. Saffo, 227 F.3d 1260, 1268-69 (10th Cir. 2000).

251 Id. at 1269.

252 United States v. Truong, 425 F.3d 1282, 1289 (10th Cir. 2005).

253 United States v. Williamson, 746 F.3d 987, 994 (10th Cir. 2014).

254 Id.

255 Id. at 994 n.2.

256 United States v. Munguia, 704 F.3d 596, 603 (9th Cir. 2012) (quoting United States v. Johal, 428 F.3d 823, 828 (9th

Cir. 2005)) (emphasis omitted); see also United States v. Galvan, 407 F.3d 954, 957 (8th Cir. 2005) (concluding that

jury instruction treating “reasonable cause to believe” as akin to actual knowledge would incorrectly render the phrase

redundant).

257 United States v. Mallory, 343 F. Supp. 3d 570, 576 (E.D. Va. 2018).

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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

258 See CRS Report R41223, Federal Conspiracy Law: A Brief Overview, by Charles Doyle. 18 U.S.C. § 371 generally

proscribes conspiracies to commit other federal crimes, and dozens of other federal statutes separately criminalize

conspiracies to engage in specific kinds of misconduct. Id. Though Section 371 carries an overt-act requirement, some

of the more specific conspiracy provisions do not. See id. at 2 (“Section 371 and a few others require at least one

conspirator to take some affirmative step in furtherance of the scheme. Many have no such explicit overt act

requirement.”).

259 CRS Report R42001, Attempt: An Overview of Federal Criminal Law, by Charles Doyle.

260 Id. at 13.

261 United States v. Bailey, 444 U.S. 394, 405 (1980).

262 See MODEL PENAL CODE §§ 5.01, 5.03 (1985). The MPC’s attempt provision has “two exceptions” to the purpose

requirement: first, “the culpability otherwise required for commission of the [attempted] crime” is all that is required

for a circumstance element, and for offenses with a result element, either purpose or “a belief that the result will occur

without further conduct on the actor’s part” is sufficient. Id. § 5.01 explanatory note.

263 E.g., United States v. Berckmann, 971 F.3d 999, 1003 (9th Cir. 2020) (“[A]ttempt crimes always require specific

intent.”); United States v. Childress, 58 F.3d 693, 707 (D.C. Cir. 1995) (“[I]t is clear that conspiracy is a ‘specific

intent’ crime.”). Though not technically inchoate, 18 U.S.C. § 2(a) also extends federal criminal liability to anyone who

“aids, abets, counsels, commands, induces or procures” the commission of an offense. Such accomplice or “aiding and

abetting” liability requires an affirmative act in furtherance of the offense and “inten[t] to facilitate that offense’s

commission,” i.e., participation in the underlying crime as “something that [the accomplice] wishes to bring about.”

Rosemond v. United States, 572 U.S. 65, 76-77 (2014). In other words, aiding and abetting liability may be thought of

as requiring a specific intent to advance the offense at issue through, at minimum, active participation “with full

knowledge of the circumstances constituting the charged offense.” Id. (quoting Nye & Nissen v. United States, 336

U.S. 613, 619 (1949)); see also United States v. Gaviria, 116 F.3d 1498, 1535 (D.C. Cir. 1997) (“The elements of

aiding and abetting an offense are (1) the specific intent to facilitate the commission of a crime by another; (2) guilty

knowledge (3) that the other was committing an offense; and (4) assisting or participating in the commission of the

offense.”).

264 United States v. Cote, 504 F.3d 682, 687 (7th Cir. 2007); see also United States v. Gracidas-Ulibarry, 231 F.3d

1188, 1192 (9th Cir. 2000) (recognizing “the doctrine that the crime of attempt requires a showing of specific intent

even if the crime attempted does not” (internal quotation marks omitted)).

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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

265 Childress, 58 F.3d at 708. One prominent treatise notes likely confusion where the objective of the conspiracy is a

separate crime, “for under such circumstances the mental state for that crime must also be taken into account.”

LAFAVE, supra note 6, § 12.2(c)(2). Put differently, “in order to sustain a judgment of conviction on a charge of

conspiracy to violate a federal statute, the Government must prove at least the degree of criminal intent necessary for

the substantive offense itself.” United States v. Feola, 420 U.S. 671, 686 (1975); see United States v. Brooks, 681 F.3d

678, 699 (5th Cir. 2012) (“Conspiracy actually has two intent elements—intent to further the unlawful purpose and the

level of intent required for proving the underlying substantive offense.”). As noted in an MPC comment, the

implication of a specific intent requirement for conspiracy appears to be that “when recklessness or negligence

suffices” for a result element of a substantive crime, “there could not be a conspiracy to commit that crime.” MODEL

PENAL CODE § 5.03 cmt. at 408 (1985).

266 See supra notes 31-35 and accompanying text.

267 8 U.S.C. § 1326(a).

268 See United States v. Carlos-Colmenares, 253 F.3d 276, 277-78 (7th Cir. 2001) (collecting cases).

269 Gracidas-Ulibarry, 231 F.3d at 1196.

270 416 F.3d 123, 126 (2d Cir. 2005). The court also held that “nothing in the plain language of the statute or in its

legislative history” suggested that “Congress intended to impose a heightened mens rea requirement in cases of

attempted reentry.” Id. at 127.

271 Id. at 128; see also United States v. Morales-Palacios, 369 F.3d 442, 449 (5th Cir. 2004) (“[I]n proving an attempted

illegal reentry it is sufficient that the government demonstrates that a previously deported alien knowingly intended to

reenter the United States—general intent with respect to the actus reus of the crime[.]”).

272 In a subsequent case, the Ninth Circuit asserted that an intervening Supreme Court decision, United States v.

Resendiz-Ponce, 549 U.S. 102 (2007), supported its view because it appeared to recognize that Section 1326

“incorporates the common law meaning of attempt.” United States v. Argueta-Rosales, 819 F.3d 1149, 1160 (9th Cir.

2016). The Supreme Court has not directly addressed the circuit split regarding Section 1326’s attempt provision,

however.

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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

273 United States v. De Leon, 270 F.3d 90, 92 (1st Cir. 2001).

274 United States v. Henry, 984 F.3d 1343, 1355 (9th Cir. 2021) (quoting United States v. Long, 301 F.3d 1095, 1103

(9th Cir. 2002)); United States v. Hernandez-Roman, 981 F.3d 138, 144 (1st Cir. 2020) (“[I]t is well-established that,

by virtue of the jury’s guilty verdict as to the conspiracy . . . , the defendant became substantively liable for the

foreseeable acts of his coconspirators in furtherance of the conspiracy.”).

275 CRS Report R43293, Corporate Criminal Liability: An Overview of Federal Law, by Charles Doyle.

276 1 U.S.C. § 1. Individual statutes may also specifically define the entities to which they apply. E.g., 18 U.S.C.

§ 1961(3) (specifying that “‘person’ includes any individual or entity capable of holding a legal or beneficial interest in

property”).

277 See, e.g., United States v. Grayson Enters., Inc., 950 F.3d 386, 407 (7th Cir. 2020) (“To prove [the company’s]

liability, the government needed to prove beyond a reasonable doubt that (1) an offense was committed by [the

company’s] agent, (2) in committing the offense, the agent intended, at least in part, to benefit [the company], and (3)

the agent acted within his authority.”); United States v. Oceanic Illsabe Ltd., 889 F.3d 178, 195 (4th Cir. 2018) (“[A]

corporation is liable for the criminal acts of its employees and agents done within the scope of their employment with

the intent to benefit the corporation.”). It is not necessary that the actions actually benefitted the entity, nor must the

employee or agent have been acting solely for the entity’s benefit. United States v. Automated Med. Laboratories, Inc.,

770 F.2d 399, 407 (4th Cir. 1985).

278 E.g., United States v. Philip Morris USA Inc., 566 F.3d 1095, 1118 (D.C. Cir. 2009) (“Because a corporation only

acts and wills by virtue of its employees, the proscribed corporate intent depends on the wrongful intent of specific

employees.”).

279 E.g., United States v. Ionia Mgmt. S.A., 555 F.3d 303, 310 (2d Cir. 2009); United States v. Potter, 463 F.3d 9, 25-26

(1st Cir. 2006). Such policies or programs may be relevant, however, to whether an agent or employee was acting in the

scope of his or her duties. Potter, 463 F.3d at 26.

280 Erin L. Sheley, Tort Answers to the Problem of Corporate Criminal Mens Rea, 97 N.C. L. REV. 773, 782 (2019).

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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

281 See United States v. Bank of New England, N.A., 821 F.2d 844, 856 (1st Cir. 1984) (“[A] corporation cannot plead

innocence by asserting that the information obtained by several employees was not acquired by any one individual who

then would have comprehended its full import. Rather the corporation is considered to have acquired the collective

knowledge of its employees and is held responsible for their failure to act accordingly.” (quoting United States v.

T.I.M.E.–D.C., Inc., 381 F. Supp. 730, 738 (W.D. Va. 1974)).

282 E.g., United States v. Sci. Applications Int’l Corp., 626 F.3d 1257, 1275 (D.C. Cir. 2010). One commentator has

framed criticism of the collective knowledge doctrine as centering on the proposition that the doctrine creates an

“unrealistic requirement that senior management keep track of the knowledge of all of its employees.” Sheley, supra

note 280, at 783.

283 MODEL PENAL CODE § 2.07(1)(c) (1985). Liability extends more broadly to corporate agents for what the MPC

deems “violations,” which generally impose strict liability, among other things. Id. §§ 2.05, 2.07(1)(a).

284 E.g., Mihailis E. Diamantis, Corporate Criminal Minds, 91 NOTRE DAME L. REV. 2049, 2068 (2016). Professor

Diamantis notes, for instance, that those at the top of the corporate hierarchy generally are “uninformed about and

uninvolved in the day-to-day activities of a corporation, where criminal action often takes place[.]” Id. at 2068-69.

285 United States v. Toledo, 739 F.3d 562, 567 (10th Cir. 2014).

286 Id. at 568 (“Self-defense only requires the defendant's reasonable belief that deadly force was necessary, not that he

exercise a duty to retreat or recognize the unavailability of reasonable alternatives.”); United States v. Earth, 984 F.3d

1289, 1300 (8th Cir. 2021) (approving jury instructions stating that if “a person reasonably believes force is necessary

to protect herself from what she reasonably believes to be unlawful physical harm about to be inflicted by another and

uses that force, then she acted in self-defense”); United States v. Biggs, 441 F.3d 1069, 1071 (9th Cir. 2006) (requiring

“a reasonable belief that the use of force was necessary to defend himself or another against the immediate use of

unlawful force”). In the context where self-defense often arises—a federal prosecution for homicide under particular

jurisdictional circumstances—an unreasonable but honest belief that the force used was necessary, amounting to

criminal negligence, may constitute “imperfect self-defense” that permits conviction of involuntary manslaughter rather

than, say, second-degree murder. Toledo, 739 F.3d at 568; United States v. Milk, 447 F.3d 593, 599 (8th Cir. 2006).

The MPC approach makes the defense unavailable where the defendant’s belief as to the unlawfulness of the conduct

being used against him is erroneous due to ignorance or a mistake regarding the law. MODEL PENAL CODE § 3.09

(1985).

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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 fouryear 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

287 Dixon v. United States, 548 U.S. 1, 7 (2006).

288 E.g., United States v. Nwoye, 824 F.3d 1129, 1136-37 (D.C. Cir. 2016) (recognizing that defendant must have had a

“reasonable fear” of imminent danger, among other things); United States v. Dixon, 901 F.3d 1170, 1176 (10th Cir.

2018) (requiring “well-grounded apprehension” of danger and direct causal relationship that could be “reasonably

anticipated” between criminal action and avoiding threatened harm ); United States v. Miller, 59 F.3d 417, 422 (3d Cir.

1995) (additionally requiring that defendant did not “recklessly place herself in a situation in which she would be

forced to engage in criminal conduct”); United States v. Dixon, 413 F.3d 520, (5th Cir. 2005), aff’d, 548 U.S. 1 (2006)

(defendant must not have “recklessly or negligently placed herself in a situation in which it was probable” she would be

forced to commit crime).

289 18 U.S.C. § 2243(a).

290 Id. § 2243(d) (providing that the government “need not prove that the defendant knew” age or requisite age

difference); United

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