Introduction

Involuntary Manslaughter at Common Law

Introduction

When a person dies and nobody meant for it to happen, the criminal law still has to decide what the death was. The answer can be no crime at all, if the death was a genuine accident that no careful person could have prevented. It can also be murder, if the defendant's conduct showed an indifference to human life that the law treats as equivalent to an intent to kill. Involuntary manslaughter occupies the ground between those poles, and a prosecutor or an examiner facing an unintended death must decide where on that range the defendant's conduct falls. Manslaughter is the unlawful killing of a human being without malice aforethought, the common-law label for the mental state that makes a killing murder, and the word "involuntary" marks the variety in which the defendant intended neither to kill nor to do grievous bodily harm.¹

At common law, involuntary manslaughter was an unintentional killing that occurred either because the defendant acted with criminal negligence or during the commission of an unlawful act that did not amount to a felony or did not fall within the felony-murder rule.² The offense therefore has two routes: a killing caused by criminal negligence (or by recklessness, in some formulations), and a killing caused by an unlawful act.³ The routes ask different questions. The first looks at how the defendant handled a danger and asks whether the risk-taking was blameworthy enough to answer for a death. The second looks at the legal wrong the defendant was committing when the death occurred, and that wrong supplies the culpability even when the defendant was neither reckless nor grossly careless about the death itself.

This chapter concentrates on the first route, because it raises the hard questions of degree: how far above ordinary carelessness the law's demand for fault must rise, and whether the defendant must actually have perceived the danger. It also follows that route to its upper boundary, where extreme recklessness stops being manslaughter and becomes what the common law calls abandoned and malignant heart murder. The line between manslaughter and murder gets its own section, since the same unintended death can fall on either side of it. The unlawful-act route is taken up afterward. Every one of these questions presupposes the structure of criminal homicide, so the first step is to place manslaughter on that map, beginning with murder and malice aforethought.