Manslaughter is an unlawful killing that doesn’t involve malice aforethought—intent to seriously harm or kill, or extreme, reckless disregard for life. The absence of malice aforethought means that manslaughter involves less moral blame than either first or second degree murder. (But plenty argue that some instances of felony murder, a form of first degree murder, involve less blameworthiness than some instances of manslaughter.) Thus, while manslaughter is a serious crime, the punishment for it is generally less than that for murder.


The two main variations of manslaughter are usually referred to as voluntary and involuntary manslaughter.

Voluntary Manslaughter

This is often called a “heat of passion” crime. Voluntary manslaughter occurs when a person:

  • is strongly provoked (under circumstances that could similarly provoke a reasonable person) and
  • kills in the heat of passion aroused by that provocation.

For “heat of passion” to exist, the person must not have had sufficient time to “cool off” from the provocation. That the killing isn’t considered first or second degree murder is a concession to human weakness. Killers who act in the heat of passion may kill intentionally, but the emotional context is a mitigating factor that reduces their moral blameworthiness.

The classic example of voluntary manslaughter involves a husband who comes home unexpectedly to find his wife committing adultery. If the sight of the affair provokes the husband into such a heat of passion that he kills the paramour right then and there, a judge or jury might very well consider the killing to be voluntary manslaughter.

Involuntary Manslaughter

Involuntary manslaughter often refers to unintentional homicide from criminally negligent or reckless conduct. It can also refer to an unintentional killing through commission of a crime other than a felony.

The subtleties between murder and manslaughter reach their peak with involuntary manslaughter, particularly because an accidental killing through extreme recklessness can constitute second degree murder.

State of Mind

Legislatures and courts have developed an entire body of law relating to the mental state differences between unintentional second degree murder and involuntary manslaughter. The determination basically boils down to how morally blameworthy the fact finder considers the defendant.

For an illustration, suppose that Rosencrantz is driving a car and runs over and kills Guildenstern. Rosencrantz might be:

  • Not guilty of a crime at all. However, if Guildenstern’s family sues Rosencrantz in a civil case, Rosencrantz might have to pay damages to Guildenstern’s heirs if Rosencrantz was negligent—that is, if Rosencrantz failed to use ordinary care.
  • Convicted of involuntary manslaughter. If Rosencrantz acted recklessly—meaning that he was more than ordinarily negligent, by driving under the influence of alcohol, for example—he could be convicted of involuntary manslaughter. (Many states have separate statutes to deal with vehicular manslaughter.)
  • Convicted of second degree murder. If Rosencrantz’s behavior demonstrated such an extreme disregard for human life that a judge or jury considers it malice aforethought, second degree murder would be the crime. For example, if Rosencrantz not only kills Guildenstern as a result of drunk driving, but does so after his license had been taken away for several previous drunk driving convictions, a judge or jury might convict him of second degree murder.