Legal Moralism, Overinclusive Offenses, and the Problem of Wrongfulness Conflation


In the Realm of Criminal Law, Antony Duff seeks to defend the view (termed “legal moralism”) that we should criminalize conduct only if it is wrongful. Skeptics of legal moralism argue that this occurs all the time in supposedly overinclusive offenses whose definitions capture not only the kind of conduct that constitutes the target wrong, but also a wider class of conduct that is not wrongful prior to prohibition. An example is statutory rape. Duff, in response, contends that such offenses need not violate the requirements of legal moralism. Having exploitative sex with juveniles is obviously wrong even prior to its legal regulation (these wrongs are mala in se). But having non-exploitative sex with juveniles is also potentially wrong, inasmuch as it involves a violation of a prohibition that society has decided is justified for instrumental reasons (such wrongs are mala prohibita). While Duff’s analysis offers an ingenious explanation for why offenses like statutory rape need not violate the bare minimum requirements of legal moralism, it simultaneously exposes separate, largely unacknowledged, problems of fair labeling and proportionality. By combining in a single offense wrongs that are primarily malum in se with ones that are primarily malum prohibitum—a process referred to as “wrongfulness conflation”—we risk treating unlike wrongs alike, imposing disproportionate punishments, and blurring offense labels. And such problems occur not just in the context of statutory rape, but also with respect to a host of other supposedly overinclusive offenses, including various forms of sexual assault.

This is a preview of subscription content, access via your institution.


  1. 1.

    Andrew Cornford, Rethinking the Wrongness Constraint on Criminalisation, 36 Law and Philosophy 615, 634 (2017). James Edwards makes a similar argument in his Criminalization Without Punishment, 23 Legal Theory 69 (2017).

  2. 2.

    Cornford, above, at 635.

  3. 3.

    I have argued elsewhere that it is problematic to use the terms mala in se and mala prohibita to refer to “offenses” as such. See, e.g., Stuart P. Green, The Conceptual Utility of Malum Prohibitum, 55 Dialogue: the Canadian Philosophical Review 33 (2016). In my view, we would do better to talk instead about malum in se and malum prohibitum “qualities” that all offenses, to one degree or another, possess. Duff himself acknowledges the scalar quality of such qualities, yet he follows the conventional practice of referring to “offenses” in a binary matter, as being one or the other. For present purposes, therefore, to respond to Duff on his own terms, I will adopt this conventional practice.

  4. 4.

    I have sought to answer these sorts of questions most recently in Stuart P. Green, Tax Evasion as Crime, in Monica Bhandari (ed.), Philosophical Foundations of Tax Law (Oxford University Press, 2017), at 57; and Stuart P. Green, Official Bribery and Commercial Bribery: Should They be Distinguished?, in Jeremy Horder and Peter Alldridge (eds.), Modern Bribery Law: Comparative Perspectives (Cambridge University Press, 2013), at 39.

  5. 5.

    Heidi Hurd, The Moral Magic of Consent, 2 Legal Theory 121, 123 (1996). See also Rollin M. Perkins and Ronald Boyce, Criminal Law (Foundation Press, 3d ed. 1982), at 1075 (making similar point).

  6. 6.

    See generally Michelle Madden Dempsey, The Volenti Maxim, in Andreas Müller and Peter Schaber (eds.), The Routledge Handbook of the Ethics of Consent (Routledge, 2018), at 187.

  7. 7.

    I have discussed this dual malum in se/malum prohibitum character of theft in Stuart P. Green, Thirteen Ways to Steal: Theft Law in the Information Age (Harvard University Press, 2012), at 102–104.

  8. 8.

    See Stuart P. Green, Lies, Rape, and Statutory Rape, in Austin Sarat (ed.), Law and Lies: Deception and Truth-Telling in the American Legal System (Cambridge University Press, 2015), at 194.

  9. 9.

    For examples of each, respectively, see Canada Criminal Code s. 273.1(1) (affirmative consent rule), German Penal Code § 174 (law enforcement officials), Model Penal Code § 213.1(2)(b) (mental incompetence). Each kind of offense is dealt with in much greater detail in my book, Criminalizing Sex: A Unified Liberal Theory (forthcoming, Oxford University Press, 2020).

  10. 10.

    For examples or discussion of each, respectively, see Garnett v. State, 632 A.2d 797 (Md. 1993) (statutory rape); Janet Halley, The Move to Affirmative Consent, Signs (2015),; Graham v. Sheriff of Logan County, 741 F.3d 1118, 1123–1124 (10th Cir. 2013) (sexual relations between guards and inmate); Ann Arstein-Kerslake, Understanding Sex: The Right to Legal Capacity to Consent to Sex, 30 Disability & Society 1459 (2015) (sexual relations with person suffering from mental deficits).

  11. 11.

    In the case of sex between law enforcement officials and persons under their control, there may well be an additional malum in se reason for criminalization, separate from the element of coercion or exploitation—namely, that such conduct constitutes a form of misconduct in office. See generally Law Commission of England and Wales, Reforming Misconduct in Public Office: A Consultation Paper,

  12. 12.

    See generally Andrew Von Hirsch, Proportionality in the Philosophy of Punishment, 16 Crime and Justice 55, 56 (1992); R.A. Duff, Punishment, Communication, and Community 135 (Oxford University Press, 2003).

  13. 13.

    See generally Andrew Ashworth, Principles of Criminal Law (Oxford University Press, 4th ed. 2003) 89–90; James Chalmers and Fiona Leverick, Fair Labelling in Criminal Law, 71 Modern L. Rev. 217, 239 (2008).

Author information



Corresponding author

Correspondence to Stuart P. Green.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Green, S.P. Legal Moralism, Overinclusive Offenses, and the Problem of Wrongfulness Conflation. Criminal Law, Philosophy 14, 417–430 (2020).

Download citation


  • Legal moralism
  • Malum in se
  • Malum prohibitum
  • Overinclusive offenses
  • Statutory rape