Murder Mitigation in the Fifty-Two American Jurisdictions: A Case Study in Doctrinal Interrelation Analysis

Abstract

The essay surveys the law in the fifty-two American jurisdictions with regard to the three doctrines that commonly provide a mitigation or defense to murder liability: common law provocation and its modern counterpart, extreme mental or emotional disturbance; the so-called diminished capacity defense and its modern counterpart, mental illness negating an offense element; and the insanity defense. The essay then examines the patterns among the jurisdictions in the particular formulation they adopt for the three doctrines, and the combinations in which those formulations commonly appear in different jurisdictions. After this review, the essay steps back to see what kinds of general conclusions can be drawn from the patterns that the survey reveals. The methodology offers a case study in the kinds of insights to be gained from such doctrinal interrelation analysis, insights about not only the doctrines at hand but also about the law-making process that produced them.

Keywords: criminal law, mitigations, defenses, homicide, common law provocation, extreme mental or emotional disturbance, EMED, diminished capacity, mental illness negating an offense element, MINOE, insanity, cognitive and control prongs, Model Penal Code, reforms