The topic of mens rea has historically played a foundational role in both motivating and guiding criminal code reform efforts. For example, the centerpiece of the most influential criminal code reform project in recent history, the American Law Institute’s Model Penal Code, is its general mens rea provisions, which define and more generally explicate the culpability requirement governing the individual offenses contained in the Code’s Special Part. The drafters of the Model Penal Code intended the element analysis reflected in these general provisions to remedy the “variety, disparity and confusion” surrounding judicial definitions of mens rea that had proliferated during the first half of the twentieth century. And it was due in large part to the drafters’ success in addressing these problems that the second half of the twentieth century witnessed a cascade of criminal code reform projects structured around the Model Penal Code’s general mens rea provisions.
In recent years, the flow of Code-based, mens rea-focused criminal code reform projects has slowed to a trickle. Even still, much of the scholarly literature on criminal code reform remains centered on mens rea issues. For the most part, the reforms proposed in this area are either relatively modest, emphasizing minor adjustments to the Model Penal Code’s general mens rea provisions, or, alternatively, quite controversial, comprising material changes to the threshold mens rea requirements dividing criminal from non-criminal conduct in many criminal codes. Often overlooked, though, is a more fundamental, but paradoxically less controversial, flaw underlying the treatment of mens rea in both model and real-world criminal codes: the pervasive disregard of the principle of proportional mens rea—roughly, the idea that those who act with a more blameworthy state of mind should receive more punishment, while those who act with a less blameworthy state of mind should receive less punishment.
This Article argues that this widespread oversight—the failure to codify legislative sentencing policies that account for key distinctions in mens rea—is normatively problematic from a variety of perspectives, providing a key justification and source of guidance for future criminal code reform efforts.
