Morality Influences How People Apply the Ignorance of the Law Defense

In four empirical studies, we showed that laypeople apply the ignorance of the law defense differently depending on the perceived morality of the defen-dant’s course of conduct at the time of the illegal act. Moral and neutral defendants who pled ignorance of the law were afforded leniency, whereas immoral defendants were sentenced as though they were not ignorant, even when defendants in all three conditions violated identical laws. These findings suggest that laypeople adopt a just deserts approach to criminal law, which influences their responsiveness to a criminal defendant’s claim to be ignorant of the law. We discuss the implications of these findings for criminal law and argue that legal doctrine should reflect laypeople’s moral intuitions. The contention that an injury can amount to a crime only when inflicted by intention is no provincial or transient notion. It is as universal and persistent in mature systems of law as belief in freedom of the human will and a consequent ability and duty of the normal individual to choose between good and evil. A relation between some mental element and punishment for a harmful act is almost as instinctive as the child’s familiar exculpatory ‘‘But I didn’t mean to[.]’’ (Morissette v. United States, 342 U.S. 246, 250–51 [1952]) Criminal conviction has two prerequisites: the actus reus (criminal act) combined with mens rea (criminal intent). The mens rea requirement is a hurdle intended to ensure that the criminal law punishes only the blameworthy or culpable, those individuals who consciously choose to do wrong. Consequently, reasonabl