Is ignorance of fact an excuse only for the virtuous?

• Author: Kahan, Dan M.
• Position: Response to article by Daniel Yeager in this issue, p. 2113

Professor Yeager's thoughtful response to my essay has convinced me that there is indeed a connection worth noting between the mistake of law doctrine and the mistake of fact doctrine. Yeager suggests that my position on mistake of law reduces to the view that someone who would be guilty of a "lesser wrong" were things as he perceived them to be may be punished for the "greater wrong" that he actually commits -- a conception of mistake of fact that has provoked fierce denunciation from commentators. But I would in fact put things slightly differently: under both doctrines courts excuse a mistaken offender when, but only when, the offender's mistake negates the inference that he has failed to internalize society's moral norms.

Regina v. Prince(1) is an excellent example. The "elopement" statute in that case made it a crime for a man to "take . . . any unmarried girl, being under the age of sixteen years, out of the possession and against the will of her father or mother."(2) Against the background of the traditional moral norms that gave rise to the statute, the critical element was not the age of the female but the absence of consent from the parents; the statute was much more concerned with protecting the "possessory rights" of fathers, who historically had negotiated the betrothal of their daughters in exchange for various kinds of commercial, social, and political benefits(3) than it was with protecting teenage females from sexual predation.(4) Thus, the court tells us, a man who took an unemancipated "girl" he knew to be eighteen years old out of the possession of her parents without the father's consent was just as bad, morally speaking, as a man who ran off with a girl he knew to be fourteen, for both could be deemed to have "trespassed on the father's rights."(5) Consequently, the court reasoned, it made no sense to excuse a man who made a mistake as to whether the girl was fourteen or eighteen.(6) But what about a man who mistakenly believed that he had the consent of the father to take a girl he knew to be only fourteen? Depending on the circumstances, there might be reason to think of him as careless, but he could not be seen as having repudiated the norm of paternal proprietorship. And accordingly, Baron Bramwell tells us, he would have had a mistake of fact defense.(7)

This analysis generalizes. When the fact in question marks the boundary line between socially approved behavior and socially disapproved behavior, courts will likely deem a mistake as to that fact to be a defense. Whether an object that one picks up from the ground is someone else's property or instead an abandoned piece of junk, for example, can mark the boundary line between culpable misappropriation and valuable salvaging; so if someone makes a mistake about that fact, he is afforded a defense to theft.(8) But when, in contrast, a fact doesn't mark that moral boundary line when even the offender's own understanding of his behavior situates him firmly within the interior of what society deems immoral -- then courts will not afford him an excuse despite his ignorance. Whether someone is a federal officer or instead a private citizen, for example, has no bearing on the moral appropriateness of assaulting that person; for that reason, a mistake about the victim's identity is no defense to a charge of assaulting a law enforcement officer.(9)

This account of the...