In the United States, the law for murder varies by jurisdiction. In most US jurisdictions there is a hierarchy of acts, known collectively as homicide, of which first-degree murder and felony murder are the most serious, followed by second-degree murder, followed by voluntary manslaughter and involuntary manslaughter which are not as serious, and ending finally in justifiable homicide, which is not a crime. However, because there are at least 52 relevant jurisdictions, each with its own criminal code, this is a considerable simplification.