In the United States, capital punishment is a legal penalty throughout the country at the federal level, in 27 states, and in American Samoa. It is also a legal penalty for some military offenses. Capital punishment has been abolished in 23 states and in the federal capital, Washington, D.C. It is usually applied for only the most serious crimes, such as aggravated murder. Although it is a legal penalty in 27 states, 20 states currently have the ability to execute death sentences, with the other seven, as well as the federal government, being subject to different types of moratoriums.

Murder is the unlawful killing of another human without justification or valid excuse committed with the necessary intention as defined by the law in a specific jurisdiction. This state of mind may, depending upon the jurisdiction, distinguish murder from other forms of unlawful homicide, such as manslaughter. Manslaughter is killing committed in the absence of malice, such as in the case of voluntary manslaughter brought about by reasonable provocation, or diminished capacity. Involuntary manslaughter, where it is recognized, is a killing that lacks all but the most attenuated guilty intent, recklessness.