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  • Heidi M. Hurd (a1) and Michael S. Moore (a2)


This essay undertakes two tasks: first, to describe the differing mens rea requirements for accomplice liability of both Anglo-American common law and the American Law Institute's Model Penal Code; and second, to recommend how the mens rea requirements of both of these two sources of criminal law in America should be amended so as to satisfy the goals of clarity and consistency and so as to more closely conform the criminal law to the requirements of moral blameworthiness. Three "pure models" of the mens rea requirements for complicity are distinguished, based on the three theories of liability conventionally distinguished in the general part of Anglo-American criminal law. One of these, the vicarious responsibility model, is put aside initially because of both its descriptive inaccuracy and its normative undesirability. The analysis proceeds using the other two models: that of the mens rea requirements for principal liability for completed crimes, and that of the mens rea requirements for attempt liability. Both the common law and the Model Penal Code are seen as complicated admixtures of these two models, the common law being too narrow in the scope of its threatened liability and the Model Penal Code being both too broad and too opaque in its demands for accomplice liability. The normative recommendation of the paper is to adopt the model for the mens rea of complicity that treats it as a form of principal liability, recognizing that the overbreadth of liability resulting from adoption of that model would have to be redressed by adopting a "shopkeeper's privilege" as an affirmative defense separate from any mens rea requirement.



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1 This is described in some detail in Moore, “The Specialness of the General Part of the Criminal Law,” in Dennis Baker, ed., The Sanctity of Life and the Criminal Law: Essays in Honour of Glanville Williams (Cambridge: Cambridge University Press, 2012).

2 See generally, Moore, Michael, “Intention as a Marker of Moral Responsibility and Legal Punishability,” in Duff, Antony and Green, Stuart, eds., The Philosophical Foundations of Criminal Law (Oxford: Oxford University Press, 2011); Hurd, Heidi and Moore, Michael “Blaming the Stupid, Clumsy, Selfish, and Weak: The Culpability of Negligence,” Criminal Law and Philosophy 5 (2011): 96148.

3 Why the Model Penal Code follows the common law in hiving off accomplice liability from principal liability is a bit of a mystery here; this, because the Code (Model Penal Code §2.03) does not adopt the version of proximate causation (the direct cause version) that requires it to conceive of accomplices as not being proximate causes of the harms or conduct that they procure or aid.

4 See Hart, H. L. A. and Honoré, Tony, Causation in the Law, 2nd edition (Oxford: Oxford University Press, 1985).

5 Williams, Glanville, Criminal Law — The General Part, 2nd edition (Cambridge: Cambridge University Press, 1960), 391.

6 Model Penal Code §2.06 (2) (a).

7 Kadish, Sanford, “A Theory of Complicity,” in Gavison, Ruth, ed., Issues in Contemporary Legal Philosophy: The Influence of H. L. A. Hart (Oxford: Oxford University Press, 1987); Kadish, Sanford, “Causation and Complicity: A Study in the Interpretation of Doctrine,” California Law Review 73 (1985): 323410, reprinted in Kadish, Sanford, Blame and Punishment (New York: Macmillan, 1987).

8 Moore, Michael, Causation and Responsibility: An Essay in Law, Morals, and Metaphysics (Oxford: Oxford University Press, 2009) 241–42.

9 For an extended discussion of when negligent actions are and are not intervening causes under prevalent doctrine, see id. 242–44.

10 The facts of State v. McVay, 47 R.I. 292, 132 A. 436 (1926).

11 “Specific intent” is a term of art unique to the criminal law, and its meaning is not univocal. Nonetheless we treat it in its dominant usage. See Michael Moore, “Intention as a Marker.”

12 Thacker v. Commonwealth, 134 Va. 767, 114 S. E. 504 (1922).

13 Model Penal Code §1.13 (9).

14 The views of theoreticians of the common law such as John Austin are described in Moore, Michael, Act and Crime: The Implications of the Philosophy of Action for the Criminal Law (Oxford: Oxford University Press, 1993; paperback edition, 2010), 189–91.

15 See, e.g., Williams, Glanville, “The Problem of Reckless Attempts,” Criminal Law Review (1983): 365–75, at 366–68; Buxton, Richard, “Circumstances, Consequences, and Attempted Rape,” Criminal Law Review (1984): 2534.

16 The Code’s introduction of “conduct,” conduct crimes, and the “nature” of conduct, is discussed critically in Robinson, Paul and Grall, Jane, “Element Analysis in Defining Criminal Liability: The Model Penal Code and Beyond,” Stanford Law Review 35 (1983): 681762, at 705–19.

17 Moore, Act and Crime, 190 n. 5, 209–210, 213–25.

18 Model Penal Code §5.01. For the common law, see Richard Buxton, “Circumstances, Consequences, and Attempted Rape.”

19 The much quoted language of Judge Learned Hand in two famous opinions. United States v. Peoni, 100 F. 2d 401, 402 (2d Cir. 1938): An accomplice must “associate himself with the venture, that he participate in it as something that he wishes to bring about, that he seek by his actions to make it succeed.” United States v. Falcone, 109 F. 2d 579, 581 (2d Circuit 1940): A co-conspirator (who will often also be an accomplice) “must in some sense promote the venture himself, make it his own, have a stake in its outcome.”

20 For example, for attempts, Cox v. State, 534 A. 2d 1333, 1336 (Md. 1988); for complicity, State v. Etzweiler, 125 N.H. 57, 480 A. 2d 870 (1984). Notice that while cases such as these purport to be based on a conceptual truth, in reality the conclusion is based on a normative argument that one should not be punished for the serious culpability of purpose when one is only negligent or reckless. A well-considered code might punish such unrealized recklessness or negligence as “reckless endangerment” and “reckless aiding,” but the punishment should be the lesser punishment reserved for such crimes and not the more serious punishment for attempt.

21 Supra, n. 12.

22 See Hurd, Heidi M, “The Moral Magic of Consent,” Legal Theory 2 (1996): 121–46.

23 See, for example, Dressler, Joshua, Understanding Criminal Law, 6th edition (LexisNexis, Matthew Bender, 2012), 470 (“an accomplice must possess two states of mind…”). The official Commentary to the Model Penal Code recognizes that accomplice liability “rests upon two factors,” one of which is culpability regarding aiding the conduct of the principal, and the other of which is culpability toward the result element of the underlying offense (321).

24 Model Penal Code §2.06 (3) (a).

25 This is not to say that he must have as his purpose that the act he is aiding will in law be an offense, for this would require knowledge of law on the accomplice’s part. While there are instances of accomplices in fact having such a law-soaked mens rea (e.g., Wilson v. People, 103 Colo. 441, 87 P.2d 5 [1939]), knowledge of law is no more required for accomplices than for principals.

26 These are the facts in United States v. Peoni, the case much discussed by the Code drafters.

27 Model Penal Code §2.06 (4).

28 The Commentaries use McVay to illustrate the intended application of Model Penal Code §2.06 (4). See Commentaries, 312–13 n. 42.

29 Model Penal Code §2.06 (4).

30 This is by using secondary mens rea as both: lessening the requirements of strong primary mens rea; and strengthening the requirements of weak primary mens rea. We chart the possibilities here in the Appendix.

31 Model Penal Code §2.06 (4).

32 Model Penal Code §1.13 (9).

33 Model Penal Code and Commentaries, 321.

34 This is a staple of the philosophy of action. See, e.g., Feinberg, Joel, “Action and Responsibility,” in his Doing and Deserving (Princeton, NJ: Princeton University Press, 1970); Rescher, Nicholas, “On the Characterization of Actions,” in Brand, Myles, ed., The Nature of Human Actions (Glenview, IL: Glencoe Press, 1970).

35 Another staple of the philosophy of action. See, e.g., Anscombe, G. E. M., Intention, 2nd edition (Ithaca, NY: Cornell University Press, 1963).

36 See, e.g., Goldman, Alvin, A Theory of Human Action (Englewood Cliffs, NJ: Prentice-Hall, 1970), 3537.

37 See Brand, Myles, Intending and Acting (Cambridge, MA: MIT Press, 1984), 66: (“There are events consisting of parts that are themselves events”).

38 Model Penal Code §5.01 (1) (a) and (b).

39 Model Penal Code §2.02 (2) (a) (i).

40 Model Penal Code and Commentaries, 311 n. 37.

41 Ibid., 414. The Code speaks of knowledge of the circumstance elements because “purpose” regarding a circumstance element is satisfied by knowledge that the circumstance exists; one needn’t be motivated by the circumstance to have “purpose” or specific intent regarding such circumstance (Model Penal Code §2.02 [2] [b][ii]).

42 With derivative crimes like complicity and attempt, there is a fourth element about which the accomplice or attempter must have some mens rea. This is the mens rea requirement of the underlying offense if the object of that mens rea goes beyond the actus reus of that underlying offense. (There will typically be specific intent underlying offenses.) Take theft as an example. Theft is taking property of another with intent to deprive that other of his property permanently. What mental state must an accomplice to theft have regarding the intent to deprive permanently? Need he, the accomplice, intend that his principal intend that the owner be deprived permanently? Or must he himself intend that the owner be deprived permanently? Or must he only know that the owner will be deprived permanently? Our own view is that here too the accomplice should have the mens rea of the underlying offense — namely, he should aid the taking with his own intent that the owner be deprived permanently. (This seems also to be the view of the court in Wilson v. People, supra n. 28.) If this is right, then for such mental state elements too, only secondary mens rea that is the same as the mens rea for the underlying offense is needed for accomplice liability.

43 In one notorious instance, the common law’s scope of liability is far too wide. We refer to the “foreseeable second crime” doctrine, according to which an accomplice to one crime is held to be an accomplice to any other crime done by the principal of the first crime, so long as that second crime is a foreseeable (or natural and probable) consequence of the doing of the first crime. As the Model Penal Code recognizes in its rejection of this common law doctrine, this makes for an extensive strict liability that is wildly disproportionate to desert.

44 The law does have some wiggle room here to expand liability slightly, as we show in our charting of strong primary mens rea in the Appendix. There are some cases in which what motivates an accomplice is not the success of his principal in the latter’s criminal actions. Rather, the accomplice could only intend that the principal attempt to do the offense, or intend to do the offense, or risk the doing of the offense; or even merely have the opportunity to try to do the offense. The common law’s specific intent to aid could allow these cases to be cases of accomplice liability. Still, these cases are rare; usually the reason one wants another to try, risk, intend, or have an opportunity, is so that this person succeeds. So these cases do not represent much expansion of common law accomplice liability. Compare Girgis, Sherif, “The Mens Rea of Accomplice Liability: Supporting Intentions,” Yale Law Journal 123 (2013): 460–94, who treats one of these rare and peripheral cases as central.

45 The concession is only arguendo, because there should be crimes of unreasonable risk creation such as reckless endangerment as provided too by the Model Penal Code.

46 Judge Posner reiterates this old suggestion in United States v. Fountain, 768 F.2d 790 (7th Cir. 1985).

47 The Reporter for the Model Penal Code’s general part, Herbert Wechsler, adopted a substantiality-of-aid threshold for his recommended knowledge mens rea for accomplices. He was, however, outvoted by the Institute in its final draft of §2.06. See Model Penal Code §2.04(3) (Tentative Draft No. 1, 1953). The New York “criminal facilitation” statute (New York Penal Code §115) partly adopts this suggestion, however, as do some courts. See United States v. Miller, 552 F. Supp. 827 (N.D Ill. 1982).

48 We say this while acknowledging that the Model Penal Code makes precisely this kind of trade-off in its attempt provisions. Model Penal Code §5.01 requires true purpose to succeed for attempters who only do a “substantial step” toward completing the crime, whereas for those who do the last act they believe to be necessary to complete the offense, mere belief that the result will occur will suffice.

49 Yaffe, Gideon, “Intending to Aid,” Law and Philosophy 33 (2014): 140.

50 Yaffe, Gideon, Attempts (Oxford: Oxford University Press, 2011), reviewed on the points raised in the text, in Moore, “Yaffe’s Attempts,” Legal Theory 19 (2013): 136–77. Essentially, for accomplices Yaffe builds on his general analysis of what it minimally requires to have an intention with respect to a circumstance element.

51 Gideon Yaffe, “Intending to Aid,” 15.

52 We each have explored independently Joseph Raz’s reading of what such stickiness of intention comes to (in terms of Raz’s “second-order, exclusionary reasons”), in Hurd, Heidi, “Challenging Authority,” Yale Law Journal 100 (1991): 1611–77, and in Moore, Michael, “Law, Authority, and Razian Reasons,” Southern California Law Review 62 (1989): 827–96.

53 In particular, whether such commitment to nonreconsideration can carry much culpability-enhancing blame with it. See Michael Moore, “Yaffe’s Attempts.” Moore (along with Michael Bratman and Scott Shapiro) voiced this objection to Gideon Yaffe’s general view as it applied to complicity mens rea, as Yaffe acknowledges in his article where Yaffe also attempts to respond to the objection. For a discussion on the adequacy of this response, see Alexander Sarch, “Condoning the Crime: The Elusive Mens Rea for Complicity,” manuscript on file with the authors and not yet submitted.

54 We are not the first to propose some such privilege. See Alexander, Larry and Kessler, Kimberly, “Mens Rea and Inchoate Crimes,” Journal of Criminal Law and Criminology 87 (1997): 1138–93, at 1192.

55 Hurd, Heidi, “Is it Wrong to Do Right When Others Do Wrong?” Legal Theory 7 (2001): 307340. For discussion of another instantiation of this more general privilege, see also Hurd, Heidi, “Stand Your Ground,” in Eric Weber, Michael, ed., The Ethics of Self-Defense (New York: Oxford University Press, 2015).

56 Why this is so is an interesting question. Our supposition is that it has to do with the agent-relativity of nonconsequentialist morality. On such a view of morality, we are to keep our own moral house in order and not let the moral shortcomings of others change our liberties any more than our obligations. But this is pretty inchoate and sketchy.

57 On why allowings are only treated like omissions even though they literally are not omissions, see Moore, Causation and Responsibility, 61–63, 142–44, 459–67. George Fletcher early on suggested that “shopkeepers” (i.e., suppliers of goods and services generally) be treated as omitters when they failed to change a regular practice of selling (Fletcher, Rethinking Criminal Law [Boston: Little, Brown, 1978], 676).

58 This is Thomas Nagel’s terminology, in his The View From Nowhere (New York: Oxford University Press, 1985).

* This essay’s origins in the mid-80’s lie in several three-way conversations over coffee at what was then called Café Roma in Berkeley on just this topic with the now deceased Sanford Kadish. We dedicate this essay to our late friend and University of California-Berkeley colleague Sandy with whom we had many happy hours parsing this and a host of other topics in criminal law theory. A preliminary sketch of this essay was defended by Hurd at the Conference on Comparative Conversations on Causation and Culpability, SUNY-Buffalo Criminal Law Center, Buffalo, New York, May, 2014; Our thanks to the many helpful comments and referee reports made at this conference, and to Alexander Sarch who separately commented on an earlier draft of the essay.


  • Heidi M. Hurd (a1) and Michael S. Moore (a2)


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