Moral capacity is a capacity to act for moral reasons and is commonly accepted as a condition of moral responsibility. I consider whether liability to criminal sanctions presupposes moral capacity.
A person lacks moral capacity when, lacking cognitive ability or moral concern, he is not in a position to act for moral reasons. In a range of cases, one might reasonably be skeptical about the moral capacity of persons who act contrary to morality. This includes cases in which persons are insane, mentally ill, highly stressed, or simply indifferent to morality. Many violent criminals fit these profiles. Furthermore, it may be impossible to sort those criminals who do from those who do not.

Nonetheless, persons who lack moral capacity are often capable of complying with the law. Their motivation to comply stems from prudential rather than moral motivation. I argue that the rational capacity of persons to comply with the law for self-interested reasons is sufficient to establish liability to criminal sanctions for criminal behavior, provided that the aim of a system of criminal law is to protect our basic rights and to advance important collective interests. Criminal agency need not presuppose moral capacity, and persons may be criminally liable even when their prudential calculations are poor or nonexistent.

But accepting this rationale for criminal liability means that we must give up retributivist accounts of criminal punishment. Liability to punishment would not establish that criminals morally deserve to suffer.