What would make one form of capital punishment cruel and unusual punishment and a different form acceptable?

The 1972 case Furman v. Georgia concerned the subject of capital punishment, which has long been a topic of national debate. Some feel it is a necessary deterrent to crime, while others believe it is morally reprehensible. In Furman v. Georgia, the Supreme Court considered whether the death penalty is subject to the prohibition in the Eighth Amendment against cruel and unusual punishment.
The 1976 case, Gregg v. Georgia upheld states rights to impose capital punishment so long as the decision for sentencing is separate from the jurys deliberations in determining the defendents guilt or innocence. The Gregg case once again, asked the Court to consider whether the death penalty can be considered cruel and unusual punishment.
Furman v. Georgia
https://www.oyez.org/cases/1971/69-5030
Gregg v. Georgia
https://www.oyez.org/cases/1975/74-6257

Click on the links to read about each case, then discuss the following questions:

• In Furman v. Georgia the justices cited both the 8th and 14th amendment. Why did justices consider the death penalty a violation of the Fourteenth Amendment?
• Do you think the death penalty is a necessary deterrent to violent crime and an acceptable social retribution, or do you think capital punishment is excessive and unconstitutional?
• The first execution following the reinstatement of the death penalty was that of Gary Gilmore in Utah, who was executed by firing squad. Many think certain types of capital punishment, such as firing squads, may be cruel and unusual punishment, while other forms, such as lethal injections, may not be.
• What would make one form of capital punishment cruel and unusual punishment and a different form acceptable?
• What constitutes cruel and unusual punishment? What issues did the Supreme Court justices consider as they answered these questions?