Nowadays, the mens rea question is more complicated than whether a crime requires proof of just “some mental element.” Though “[t]he common law and older codes often defined an offense to require only a single mental state,” the publication of the Model Penal Code in 1962 led to “a general rethinking of traditional mens-rea analysis.” Among the components of this rethinking was a recognition that the question of mens rea must “be faced separately with respect to each material element of the crime.” In other words, the Model Penal Code showed that the question whether to require proof of “some mental element” must be addressed not in relation to the crime as a whole but rather in relation to each individual objective element of the crime. And so it also showed that the mens rea principle must operate, somehow, at the level of individual material elements.
Unfortunately, nobody seems to know which material elements are subject to the mens rea presumption. Students in the traditional first-year Criminal Law course learn two very different versions of the presumption. The first is the Model Penal Code version, which requires proof of some mental state—purposely, knowingly, recklessly, or negligently—with respect to every material element of the offense, unless the offense is a mere “violation.” The second is the judge-made version, which requires proof of some mental state only with respect to those “statutory elements that criminalize otherwise innocent conduct.” Justice (then Judge) Sotomayor precisely, if somewhat awkwardly, summarized this judge-made version of the presumption in her very first opinion as a judge of the Second Circuit. “Absent clear congressional intent to the contrary,” she said, “statutes defining federal crimes are . . . normally read to contain a mens rea requirement that attaches to enough elements of the crime that together would be sufficient to constitute an act in violation of the law.”
Neither the Model Penal Code’s nor the courts’ version of the mens rea presumption is entirely right.
