In the United States, death penalty varies by jurisdiction and is applied rarely. In practice death penalty is applied generally only for aggravated murder and even more rarely for felony murder or contract killing. While some of the states in the U.S. have been without death penalty, other states have carried out death penalty.
The case of William Henry Furman v. State of Georgia, 408 U.S. 238 (1972), is a United States Supreme Court ruling on the requirement for a degree of consistency in the application of the death penalty. The Supreme Court consolidated Jackson v. Georgia and Branch v. Texas with the Furman decision, and thus also invalidated the death penalty for rape.
In the case of Woodson v. North Carolina, 428 U.S. 280(1976) the mmandatory death penalty law was declared unconstitutional.
In Thompson v. Oklahoma, 487 U.S. 815(1988), it was held that youths younger than 16 years old at the time of their offense cannot be constitutionally executed.
In Ford v. Wainwright, 477 U.S. 399 (1986) it was held that it is unconstitutional to execute a person who is insane.