Final answer:
The court has used a standard that assesses whether a death penalty statute provides a clear, controlled process for its imposition and isn't applied arbitrarily or capriciously, considering factors like the gravity of the crime and the characteristics of the defendant.
Step-by-step explanation:
The standard used by the court to determine whether a death penalty statute is constitutional has evolved through a series of landmark cases. According to decisions such as Jurek v. Texas, Gregg v. Georgia, and others, constitutionality is determined by whether the statute includes a mechanism for narrowing the class of individuals eligible for the death penalty, often by weighing aggravating and mitigating factors, and ensuring that the death sentence is not applied in an arbitrary or capricious manner.
In the case of Gregg v. Georgia, the Supreme Court held that the death penalty itself is not unconstitutional under the Eighth Amendment, provided that the state's statute narrowly defines and controls the process for imposing a death sentence. This and related rulings from the same period effectively lifted the moratorium on executions that had been in place since Furman v. Georgia (1972), where the Supreme Court found that inconsistent imposition of the death penalty constituted cruel and unusual punishment.
Subsequent rulings such as Kennedy v. Louisiana and Roper v. Simmons have further clarified that the death penalty is unconstitutional when applied to certain crimes or groups, such as non-homicide offenses or juvenile offenders respectively. Moreover, Baze v. Rees confirmed that certain methods of execution, such as the three-drug cocktail used for lethal injections, are constitutional.