Eighth Amendment to the United States Constitution in the context of Capital punishment in the United States

Atkins v. Virginia, 536 U.S. 304 (2002), is a case in which the Supreme Court of the United States ruled 6–3 that executing people with intellectual disabilities violates the Eighth Amendment's ban on cruel and unusual punishments, but that states can define who has an intellectual disability. At the time Atkins was decided, 18 of the 38 death penalty states exempted mentally disabled offenders from the death penalty.

Twelve years later in Hall v. Florida the U.S. Supreme Court narrowed the discretion under which U.S. states can designate an individual convicted of murder as too intellectually incapacitated to be executed.

The Judiciary Act of 1789 (ch. 20, 1 Stat. 73) is a United States federal statute enacted on September 24, 1789, during the first session of the First United States Congress. It established the federal judiciary of the United States. Article III, Section 1 of the Constitution prescribed that the "judicial power of the United States, shall be vested in one Supreme Court, and such inferior Courts" as Congress saw fit to establish. It made no provision for the composition or procedures of any of the courts, leaving this to Congress to decide.

The existence of a separate federal judiciary was controversial during the debates over the ratification of the Constitution. Anti-Federalists had denounced the judicial power as a potential instrument of national tyranny. Indeed, of the ten amendments that eventually became the Bill of Rights, five (the fourth through the eighth) dealt primarily with judicial proceedings. Even after ratification, some opponents of a strong judiciary urged that the federal court system be limited to only a Supreme Court and, perhaps, local admiralty judges. Congress, however, decided to establish a system of federal trial courts with broader jurisdiction, thereby creating an arm for enforcement of national laws within each state.

Powell v. Texas, 392 U.S. 514 (1968), was a United States Supreme Court case that ruled that a Texas statute criminalizing public intoxication did not violate the Eighth Amendment protection against cruel and unusual punishment. The 5–4 decision's plurality opinion was by Justice Thurgood Marshall. Justice Hugo Black and Byron White each wrote separate concurring opinions while Justice Abe Fortas dissented.

The United States Constitution contains several provisions regarding the law of criminal procedure.

Petit jury and venue provisions—both traceable to enumerated complaints in the Declaration of Independence—are included in Article Three of the United States Constitution. More criminal procedure provisions are contained in the United States Bill of Rights, specifically the Fifth, Sixth, Seventh and Eighth Amendments. With the exception of the Grand Jury Clause of the Fifth Amendment, the Vicinage Clause of the Sixth Amendment, and (maybe) the Excessive Bail Clause of the Eighth Amendment, all of the criminal procedure provisions of the Bill of Rights have been incorporated to apply to the state governments.

Furman v. Georgia, 408 U.S. 238 (1972), was a landmark criminal case in which the United States Supreme Court decided that arbitrary and inconsistent imposition of the death penalty violates the Eighth and Fourteenth Amendments, and constitutes cruel and unusual punishment. It was a per curiam decision. Five justices each wrote separately in support of the decision. Although the justices did not rule that the death penalty was unconstitutional, the Furman decision invalidated the death sentences of nearly 700 people. The decision mandated a degree of consistency in the application of the death penalty. This case resulted in a de facto moratorium of capital punishment throughout the United States. Dozens of states rewrote their death penalty laws, most of which were upheld in the 1976 case Gregg v. Georgia.

The Supreme Court consolidated the cases Jackson v. Georgia and Branch v. Texas with the Furman decision, thereby invalidating the death penalty for rape; this ruling was confirmed post-Gregg in Coker v. Georgia. The Court had also intended to include the case of Aikens v. California, but between the time Aikens had been heard in oral argument and a decision was to be issued, the Supreme Court of California decided in California v. Anderson that the death penalty violated the state constitution; Aikens was therefore dismissed as moot, since this decision reduced all death sentences in California to life imprisonment.