Final answer:
The Supreme Court case Furman v. Georgia in 1972 declared existing death penalty statutes unconstitutional. Gregg v. Georgia in 1976 upheld a revised statute, reintroducing the death penalty with constitutional safeguards. The death penalty remains legal but is substantially limited by subsequent Supreme Court decisions.
Step-by-step explanation:
Supreme Court and the Death Penalty
The Supreme Court case that declared existing death penalty statutes unconstitutional and effectively abolished the death penalty in the United States was Furman v. Georgia, 408 U.S. 238 (1972). However, this moratorium on executions was short-lived. In Gregg v. Georgia, 428 U.S. 153 (1976), the Court upheld Georgia's revised death penalty statute, which introduced measures to narrow the class of defendants eligible for the death penalty. This decision overturned the prior ruling in Furman by allowing the death penalty under revised state statutes that addressed the previously identified constitutional flaws.
Notably, Kennedy v. Louisiana, 554 U.S. 407 (2008), defined a limitation on the death penalty, declaring it unconstitutional in all cases that do not involve murder or crimes against the state. In recent years, the Supreme Court has continued to narrow the application of the death penalty by prohibiting its application to defendants with intellectual disabilities or those who were minors at the time of their crimes.
Overall, while Furman v. Georgia temporarily abolished the death penalty, the Supreme Court's later rulings allowed it to continue under revised legal frameworks, though with significant restrictions on its application.