In Stanford v. Kentucky, the U.S. Supreme Court ruled in a 5-4 decision that it was not unconstitutional for states to impose capital punishment on offenders who were at least 16 years old when they committed their crimes. The case involved Kevin Stanford, who had been sentenced to death in Kentucky for a murder he committed at age 17. He argued that his execution would violate the Eighth Amendment's prohibition of cruel and unusual punishment because of his age at the time of the crime. However, the majority opinion held that there was no national consensus against executing young offenders aged 16 or above and therefore it did not offend "the evolving standards of decency" used to interpret what constitutes cruel and unusual punishment under Eighth Amendment jurisprudence.

In the dissenting opinion for Stanford v. Kentucky, Justice Brennan argued that executing individuals who were under 18 at the time of their crimes was cruel and unusual punishment, violating the Eighth Amendment. He contended that societal standards had evolved to view such executions as unacceptable; therefore, they should be deemed unconstitutional. Brennan also pointed out inconsistencies in determining which juvenile offenders are mature enough to face capital punishment and criticized using age as a determinant for death penalty eligibility. Furthermore, he emphasized international disapproval of executing minors as evidence of evolving standards of decency against it.