The Mistake of Fact Defense and the Reasonableness Requirement

This article examines specifically the mistake of fact defense and its disparate treatment under these two systems of justice. The British approach is to retain a subjective element in the mistake of fact defense, while American courts impose an objective reasonableness requirement. The substantive criminal law approach, utilizing the concept of mens rea, will be discussed first, and will be followed by a treatment of recent American constitutional developments in the area of burden of proof standards in their criminal context. Finally, two factually similar rape cases, one British and one American, will be analyzed to show the present contrasting results when the same problem is presented. Some suggestions for legislative or judicial reform will follow. This article suggests that American courts could remedy the situation by eliminating the reasonableness requirement in mistake of fact cases, either for reasons of logic or because the due process requirements of the Constitution require them to do so. American legislatures (or courts construing the mens rea requirements of particular statutes) could alternatively resolve the problem by enacting general intent crimes requiring recklessness, instead of unreasonableness, as a minimum standard for conviction