Although many states continue to use capital punishment, several Supreme Court decisions heavily factored into when the punishment could be used and which defendants could receive capital punishment. There are three landmark decisions that affected capital punishment.
Atkins v. Virginia
One concern in cases where the defendant is given the death penalty is their ability to comprehend the situation and thereby their amount of culpability in the crime. In Atkins v. Virginia, it was ruled that the death penalty was unconstitutional for people who are intellectually disabled. People who fit the standard of intellectual disability and who were sentenced to death were resentenced to life imprisonment. In some states, there were additional challenges with determining intellectual disability. For example, in Moore v. Texas, it was determined the state's definition of intellectual disability relied on lay standards about intellectual disability and not current medical standards.
Coker v. Georgia
At one point, the death penalty could be imposed for crimes other than murder, such as rape. One of the concerns with this approach is the disproportionate amount of people of color sentenced to death because of rape. A 1977 ruling in Coker v. Georgia determined it was unconstitutional to sentence a defendant to death for rape, but this decision did not include child rape. A subsequent decision in Kennedy v. Louisiana prohibited the imposition of the death penalty for defendants convicted of child rape. Defendants who were on death row for either rape or child rape had their sentences overturned and some went back to court for a new punishment hearing.
Roper v. Simmons
In 2005, the U.S. Supreme Court ruled that it was unconstitutional to impose the death penalty on defendants that were juveniles at the time of their crime. The defendants had their sentences reduced to life without parole (LWOP) after the ruling, which provoked another decision. Juveniles are generally considered impulsive and less cognizant about the consequences of their actions, reducing their culpability. A mandatory LWOP sentence for crimes other than murder was eventually overturned and required judges and juries to take into consideration the offender's age at the time of the offense when recommending a sentence. This ruling does not mean juveniles in murder cases cannot be sentenced to LWOP, but it cannot be mandatory for juveniles.
The arbitrariness and in some types of cases mandated use of the death penalty was overturned by narrowing the scope of capital cases. These cases acknowledged reduced culpability in some instances and increased the fairness in the application of the death penalty.
Reach out to a local criminal defense lawyer if you have more questions about the death penalty.