Introduction

Heat of Passion Manslaughter

Introduction

At common law, murder is the unlawful killing of a human being with malice aforethought.¹ Malice aforethought is the term of art for the guilty mental states that mark a killing as murder, and the most familiar of them is an intent to kill.² A defendant who set out to cause a death therefore satisfies the mental element of murder by definition. Voluntary manslaughter is the label the common law attaches to one group of such killings: an intentional killing that would otherwise be murder, but that occurred in the heat of passion, following adequate provocation, and before a reasonable cooling-off period had elapsed.³ That raises the question this chapter answers: why does the law lower the grade of the offense when the defendant meant to kill?

That scenario is the classic fact pattern for mitigation, and the reason the law mitigates depends on what provocation does and does not do. It does not justify the killing, and it leaves the defendant criminally responsible for a homicide. It lowers the grade because the killing grew out of a temporary breakdown in self-control that the provoking event produced, which makes the defendant less culpable than someone whose killing reflects a settled wickedness of heart. Under the common law, a killing that would otherwise be murder is treated as manslaughter when the victim provoked the defendant, the provocation was of a kind that could lead a reasonable person in the defendant's circumstances to act in the heat of passion, and the defendant had no opportunity to cool off.⁴

The doctrine is applied through a four-part sequence that alternates between objective questions (measured against an ordinary person) and subjective questions (measured by this defendant's actual state of mind). The sequence asks whether the provocation was adequate, whether the defendant was actually provoked, whether a reasonable person would still have been aflame when the killing occurred, and whether this defendant had in fact cooled. Other routes to voluntary manslaughter, such as imperfect self-defense, and the Model Penal Code's extreme emotional disturbance approach are taught elsewhere, because this chapter covers only the common-law heat-of-passion test. The first section below explains why the law mitigates at all and why the test takes this two-sided shape.