HAMDANI_BOOK 3/20/2007 8:12 PM ESSAY MENS REA AND THE COST OF IGNORANCE Assaf Hamdani* HIS Essay advances a new understanding of the controversial T doctrine of strict criminal liability. While the conventional view holds that strict criminal liability aims at alleviating the administra- tive burden of proving defendants’ mental state, this Essay argues that this doctrine also can induce genuinely ignorant offenders to acquire information. The predominant mens rea standard assures ignorant offenders that they can engage in the prohibited conduct without being penalized. This drawback, however, is mitigated when offenders find that the market imposes too high a cost on ignorance. If ignorance is sufficiently costly, offenders will take steps to become (or remain) informed notwithstanding the adverse incentive created by the mens rea standard. The Essay thus predicts that, other things being equal, strict liability is likely to be especially useful in those elements of a criminal offense for which ignorance is virtually cost- less. The Essay demonstrates the illuminating power of this explana- tion by analyzing the application of strict liability to liquor sale to minors, statutory rape, child pornography, regulatory offenses, criminal liability of corporate officers, and mistakes of law and fact. The Essay concludes by exploring whether alternative doctrines may induce offenders to acquire information without producing the harsh and unfair consequences often attributed to strict liability. INTRODUCTION...................................................................................... 416 I. EXISTING EXPLANATIONS ............................................................... 420 * Assistant Professor, Bar Ilan Faculty of Law. This Essay greatly benefited from comments and suggestions by Lucian Bebchuk, Avi Bell, Tsilly Dagan, Miriam Gur- Arye, Dan Kahan, Ruth Kannai, Louis Kaplow, Alon Klement, Reinier Kraakman, Dan Markel, Gideon Parchamovsky, Steve Shavell, and participants at the Law & Economics Workshop at Harvard Law School and the faculty seminar at Tel Aviv Faculty of Law, as well as from the excellent research assistance of Dan Rinot. I would like to thank the John M. Olin Center for Law, Economics, and Business at Harvard Law School for providing financial support. 415 HAMDANI_BOOK 3/20/2007 8:12 PM 416 Virginia Law Review [Vol. 93:415 A. Difficulty of Proof.................................................................... 421 B. Other Justifications ................................................................. 423 II. COSTLY IGNORANCE AND STRICT LIABILITY................................... 425 A. The Drawback of Mens Rea..................................................... 425 B. Introducing the Cost of Ignorance........................................... 430 1. The Impact of Ignorance Costs ......................................... 430 2. When Is Ignorance Costly? ............................................... 433 C. Optimal Ignorance................................................................... 434 D. Taking Stock ............................................................................ 436 III. THE JURISPRUDENCE OF STRICT LIABILITY ..................................... 437 A. Victims’ Age............................................................................. 438 1. Statutory Rape................................................................... 438 2. Liquor Sale to Minors ....................................................... 440 3. Child Pornography............................................................ 441 4. National Firearms Act....................................................... 443 B. Environmental Violations........................................................ 444 C. Corporate Officers................................................................... 445 D. Mistake of Law ........................................................................ 448 IV. IMPLICATIONS ................................................................................. 449 A. Reframing the Debate.............................................................. 450 B. Evaluating Alternatives ........................................................... 451 1. Willful Ignorance............................................................... 452 2. Negligence......................................................................... 453 3. Direct Regulation .............................................................. 455 CONCLUSION......................................................................................... 457 INTRODUCTION Strict criminal liability—that is, criminal liability without proof of mental state, negligence, or other fault—is highly controversial, surprisingly persistent, and notoriously unpredictable. For decades, criminal law scholars have argued that this doctrine punishes inno- 1 cent actors and is thus unjust, unconstitutional, and ineffective. 1 See, e.g., Henry M. Hart, Jr., The Aims of the Criminal Law, 23 Law & Contemp. Probs. 401, 422 (1958) (positing that strict criminal liability condemns the blameless without any justification); James J. Hippard, Sr., The Unconstitutionality of Criminal Liability Without Fault: An Argument for a Constitutional Doctrine of Mens Rea, 10 Hous. L. Rev. 1039, 1040 (1973) (“Strict liability crimes are . unconstitutional anomalies that the Supreme Court should have suppressed long ago.”); Herbert L. Packer, Mens Rea and the Supreme Court, 1962 Sup. Ct. Rev. 107, 109 (“[T]o punish HAMDANI_BOOK 3/20/2007 8:12 PM 2007] Mens Rea and the Cost of Ignorance 417 But despite nearly unanimous vilification, strict liability continues to occupy an important place in modern criminal law.2 Strict liabil- ity is not only normatively questionable; it is also of indeterminate scope. Commentators have thus far failed to explain why it governs only certain elements of specific offenses.3 This disarray leaves troubling uncertainty concerning the reach of many criminal of- fenses, including statutory rape, child pornography, environmental violations, and some terrorism-related crimes.4 This Essay will offer a novel explanation for the role of strict li- ability in criminal law. This new understanding clarifies the juris- prudence of strict liability and illuminates some pieces of criminal law doctrine that have thus far resisted satisfactory explanations. More importantly, by identifying the tradeoff that often underlies the choice between mens rea and strict liability, this new under- standing allows lawmakers to devise less draconian alternatives to strict criminal liability. The conventional view holds that strict liability is designed to overcome the difficulty of proving defendants’ subjective mental states, as required under the predominant mens rea standard.5 But if this is the reason, why use strict liability in selected offenses only? The common answer is that strict liability should govern conduct without reference to the actor’s state of mind is both inefficacious and un- just.”). 2 See John L. Diamond, The Myth of Mortality and Fault in Criminal Law Doctrine, 34 Am. Crim. L. Rev. 111, 116–17 (1996) (“[M]ost states utilize strict liability punish- ments and continue to characterize these acts as crimes.”); Alan C. Michaels, Consti- tutional Innocence, 112 Harv. L. Rev. 828, 831 (1999) (“Strict liability has endured decades of unremitting academic condemnation.”). But cf. Richard Singer & Douglas Husak, Of Innocence and Innocents: The Supreme Court and Mens Rea Since Her- bert Packer, 2 Buff. Crim. L. Rev. 859, 861 (1999) (arguing, in the context of mens rea, “that the United States Supreme Court has recently reinvigorated its concern with protecting innocent persons as the bedrock of federal criminal law”). 3 The frustration produced by the indeterminate jurisprudence of strict criminal li- ability is best captured in the famous quote: “Mens rea is an important requirement, but it is not a constitutional requirement, except sometimes.” Packer, supra note 1, at 107. 4 See, e.g., Randolph N. Jonakait, The Mens Rea for the Crime of Providing Mate- rial Resources to a Foreign Terrorist Organization, 56 Baylor L. Rev. 861, 862 (2004); Susan F. Mandiberg, The Dilemma of Mental State in Federal Regulatory Crimes: The Environmental Example, 25 Envtl. L. 1165, 1166–69 (1995); Jarrod Forster Reich, Note, “No Provincial or Transient Notion”: The Need for a Mistake of Age Defense in Child Rape Prosecutions, 57 Vand. L. Rev. 693, 694–97 (2004). 5 See infra Section I.A. HAMDANI_BOOK 3/20/2007 8:12 PM 418 Virginia Law Review [Vol. 93:415 “public welfare” offenses—modern regulatory violations carrying relatively light penalties.6 This view, however, fails to account for the reality in which strict liability is also used in relatively severe, traditional offenses, such as statutory rape. This account also can- not explain why a single offense requires strict liability for one element but not for others. The explanation I will offer consists of two components. The first highlights a fundamental drawback of the dominant standard of criminal liability: mens rea. By making knowledge of certain facts a precondition for criminal liability, mens rea allows offenders to engage in misconduct and evade liability as long as they are genuinely ignorant. Strict liability, in contrast, deters offenders re- gardless of their state of mind.7 This insight, however, only intensi- fies the mystery surrounding the limited place of strict liability in criminal law. If mens rea is