The constitutionality of capital punishment has been challenged in the Supreme Court in many cases for more than five decades. The Supreme Court temporarily halted the death penalty in 1972 (Furman v. Georgia) when it ruled that the punishment was administered too arbitrarily. States that sought to use the death penalty rewrote their laws to require more careful deliberation, especially through use of a separate proceeding after conviction focused solely on the sentence (to execute or to imprison?) and using an explicit consideration of aggravating and mitigating factors. Aggravating factors are those that make the crime or the murderer worse than those in other murder cases, such as a killing during the commission of a separate felony or a murderer with a long criminal record. Mitigating factors are those that make the individual or the crime less deserving of the death penalty, such as youthful age, victimization during childhood, or limited mental capacity. The Supreme Court approved a reactivation of the death penalty under these new statutes in 1977 (Gregg v. Georgia).
The Supreme Court has prohibited the application of capital punishment to certain categories of crimes and individuals when such applications were ruled to violate the 8th Amendment prohibition on cruel and unusual punishments. For example:
- No death penalty permitted for the crime of rape of an adult woman (Coker v. Georgia, 1977)
- No death penalty for the rape of a child (Kennedy v. Louisiana, 2008)
- No death penalty for someone who commits a murder prior to attaining the age of 18 (Roper v. Simmons, 2005)
- No death penalty for developmentally disabled individuals who commit murders (Atkins v. Virginia, 2002).
Because the Supreme Court during its 2021-2022 term moved swiftly to reverse longstanding precedents concerning various major issues (e.g., the right to privacy, separation of church and state, and the authority of government agencies), commentators wonder whether the Court might revisit some of these capital punishment issues. The newly constituted majority on the Court, with the addition of three conservative appointees of President Donald Trump, has shown it will decide many issues differently than did justices during prior Supreme Court eras.
The Supreme Court has heard several cases presenting arguments about lethal injection as a method of execution. Because of problems with lethal injections, including whether the method can inflict torturous pain, these cases seek to have the Court declare that this method violates the Cruel and Unusual Punishments Clause. The Court has consistently declared that no one has yet presented sufficient evidence and arguments to justify such a ruling (e.g., Baze v. Rees, 2008).