Mezzanine Law: The Care of a Mens Rea Presumption
Amelia D. Lewis Professor of Constitutional and
Criminal Law in the Sandra Day O’Connor College of Law
Arizona State University
Many of the modern challenges of mens rea, the mental state element of crime, stem from the purported ambiguities of legislation. Sometimes the issue involves uncertainty in interpreting a specified mental state—whether, for instance, “willfully” requires an appreciation that one is violating the law, thereby allowing claims of ignorance through a mistake-of-law defense. At other times, a mens rea requirement may raise questions as to its application within a statute, like whether to distribute an explicit mental state across the elements of a crime. But when these interpretive possibilities prove impossible as a matter of language or reason, or when a provision is entirely bereft of any culpable mental state, the issue takes on a distinctly normative character: whether to infer a mental state requirement based on a free-floating presumption in favor of mens rea. The presumption is born of a belief that mens rea is not just a matter of legislative grace in enacting criminal statutes. At the same time, it is tempered by a profound judicial ambivalence about imposing constitutional constraints on criminal culpability. The mens rea presumption thus exists in the space between statutory law and constitutional law, providing an example of what I will call “mezzanine law.” This essay sketches the concept and its application to some contemporary problems of culpability.