The partial defense of provocation provides that a person who kills in the heat of passion brought on by legally adequate provocation is guilty of manslaughter rather than murder. The defense traces back to the twelfth century and exists today, in some form, in almost every U.S. state and other common law jurisdictions. But long history and wide application have not produced agreement on the rationale for the doctrine. To the contrary, the search for a coherent and satisfying rationale remains among the main occupations of criminal law
The dominant scholarly view holds that provocation is best explained and defended as a partial excuse on the grounds that the killer’s inflamed emotional state so compromised his ability to conform his conduct to the demands of reason and law as to render him substantially less blameworthy for his conduct. In contrast, a small minority of scholars have maintained, without significant argumentative support, that provocation is best understood as a partial justification on the ground that the provoked killing is less
wrongful than is an unprovoked killing, ceteris paribus. Recently, other commentators have argued that provocation mitigation is neither partial excuse nor partial justification.
Against all of these familiar positions, we argue that partial excuse and partial justification are necessary and sufficient conditions for provocation manslaughter. In our view, an intentional killing deserves to be punished and labeled as manslaughter rather than murder only when, because of provocation, this particular killing is significantly less wrongful than the standard intentional killing and when, because of the actor’s partial lack of control, he is less blameworthy for committing an act that remains all-things-considered wrongful. In elaborating and defending our account, we rebut the oft-repeated but rarely challenged propositions that justification and excuse, even in partial forms, are mutually exclusive, and that the very notion of partial justification is incoherent. We also draw forth implications for how the sentencing ranges for murder and manslaughter should be related.