Faultless mistake of fact: Justification or excuse?

I. Introduction According to Lafave and Scott, "No area of the substantive criminal law has traditionally been surrounded by more confusion than that of ignorance or mistake of fact or law."[1] However, the authors go on to say that "[i]n actuality, the basic rule is extremely simple: ignorance or mistake of fact or law is a defense when it negatives the existence of a mental state essential to the crime charged."[2] Typically then, a mistake of fact on the part of a defendant at the time of the offense serves to undergird a failure of proof defense. In a failure of proof defense, the defense attempts to show that an element essential to the definition of the crime is not present and, thus, that the prosecution has not proved its prima facie case. Regina v. Morgan provides an example of the utilization of a defense of this sort.[3] In Morgan, the Lords concluded that since Morgan's co-appellants sincerely believed that the alleged victim consented to intercourse (although in fact she had not), it cannot be said that they intended the act qua prohibited act, regardless of the reasonableness or unreasonableness of each of their beliefs regarding her consent. Thus, according to the Lords, controversial decision, the mens rea requirement is not met in circumstances in which a defendant charged with rape sincerely believed, at the time of the act, that the intercourse was consensual. In effect, the mistake of fact negatives defendant intent. An affirmative defense may also be founded upon a defendant's mistake of fact. A defense of this sort may concede that the prosecution has made its prima facie case, that is, that the conduct and culpability requirements for the crime are met, but nevertheless contend that the defendant ought to be found not guilty for other reasons, for example, because the defendant's actions were justified or excused. People v. Young serves as an example of the application of such a defense.[4] In this case, Young went to the aid of an eighteen-year-old individual who was struggling against two assailants. According to Young, he intervened because the youth was crying and trying to escape the clutches of the two men who, in the struggle, had nearly removed the young man's pants. As a consequence of Young's intervention, one of the men believed by Young to be an unlawful assailant suffered a broken leg. Unbeknownst to Young, though, the two assailants were in fact plain clothes detectives. So, unfortunately for Young and the detectives, Young was mistaken about the facts of the situation. Specifically, he held the erroneous belief that the two assailants were ordinary civilians, not police officers carrying out their duties. However, although Young knowingly and purposely attacked the two men who turned out to be officers of the law (and, so, mens rea, in addition to the other material elements for assault, was clearly present),[5] Young had an affirmative defense for his conduct.[6] The New York State legislature provides those with reasonable but mistaken beliefs with the following defense: "A person may...use physical force upon another person when and to the extent he reasonably believes such to be necessary to defend himself or a third person from what he reasonably believes to be the use or imminent use of unlawful physical force by such other person."[7] In this paper, I shall focus upon the affirmative defense of actions similar to Young's, actions "based upon a faultless mistake of fact."[8] I shall advance the following thesis: action based upon a faultless mistake of fact are appropriately deemed excused, not justified, by morality and by the law.[9] In Section II, I explicate the basic distinction between the notions of justification and excuse as well as suggest why the distinction is important. In Section III, I provide an analysis of the notion faultless mistake of fact. Next, in Section IV, I criticize the competing analysis of Kent Greenawalt and provide arguments for the central thesis of my paper. …