The U.S. Supreme Court is hearing arguments Monday on whether executing prisoners by lethal injection violates a constitutional ban on cruel and unusual punishment.
Attorneys for two death row inmates in the eastern state of Kentucky argue that lethal injections can cause unnecessary pain and suffering.
The three-drug cocktail injection that Kentucky uses for executions has one drug to make the prisoner unconscious, another to paralyze the body and a third to stop the heart.
Opponents to the method argue that if the first drug does not work, the inmate would not be able to move but would feel excruciating pain.
Executions in the United States have come to a halt until the court issues its ruling, expected by June.
Last month, the northeastern state of New Jersey became the first U.S. state to abolish the death penalty in more than 40 years. Inmates sentenced to death in New Jersey will now be given life sentences without parole.
Thirty six U.S. states allow the death penalty.
Some information for this report was provided by AP and Reuters.