At common law, murder was defined as killing with malice aforethought. Malice could be understood in two ways: express and implied. Express malice murders included killings where a person intended to cause death or grievous bodily harm to another. Implied malice included killings that occurred while a person was committing a felony (also called felony murder) or deaths resulting from an action that displayed a depraved indifference to human life (also called depraved heart murder). Today, malice aforethought is the mental element (or mens rea) required to prove murder in the first degree in federal law and in some states. For example, in 18 U.S. Code § 1111, murder is defined as “the unlawful killing of a human being with malice aforethought.” Generally, a killing does not qualify as murder in the first degree unless it was committed after premeditation and deliberation. Thus, a killing that occurs in the heat of passion would not qualify.
Many states, as well as the Model Penal Code (MPC) have since abandoned the language of malice aforethought in their statutes, preferring for language more precise than “malice.” Most of these jurisdiction instead focus on language of intent and premeditation. Further, some jurisdictions have done away with the premeditation requirement altogether, such as in New York.
[Last updated in June of 2020 by the Wex Definitions Team]