Capital punishment, also referred to as the death penalty, has a long history as a feature of human society and has been used in the United States since the colonial era. Under American constitutional law, states have the right to apply their own criminal statutes, including capital punishment. As of June 2017, eighteen US states have abolished the death penalty. In states that continue to enforce capital punishment, the majority of executions are carried out by lethal injection. A limited number of states also authorize a range of other execution methods, including electrocution, gas inhalation, hanging, and firing squad. These methods have become increasingly rare, however.