The US Supreme Court Wednesday ruled that lethal injection was constitutional in a landmark ruling set to pave the way for executions to resume after a lull of more than six months.
The judges ruled by seven for and two against that the risk of suffering to those executed by lethal injection did not constitute "cruel and unusual punishment" which is barred under the US constitution.
"Petitioners have not carried their burden of showing that the risk of pain from maladministration of a concededly humane lethal injection protocol, and the failure to adopt untried and untested alternatives, constitute cruel and unusual punishment," the judges said in an opinion written by Chief Justice John Roberts.
Lethal injection is the most commonly used form of execution across the United States. Some 53 people were executed in the US in 2006, after the numbers reached a peak of 98 in 1999.
Several death row inmates, led by a pair from Kentucky, had urged the Supreme Court to rule on whether lethal injection violated the constitution.
They had argued that the three-part injection method in which the first part sedates the inmate, the second paralyzes the muscles and the third stops the heart, caused needless suffering in some cases.
If the execution goes according to plan, the inmate quickly loses consciousness and dies in a few minutes. But if the anaesthesia is not properly administered, the inmate can suffer immensely.
In a December 2006 execution, convicted murderer Angel Nieves Diaz had to be given two lethal doses after a needle missed his vein and pierced tissue instead. Grimacing as he struggled to breathe, his execution took 34 minutes.
Following the incident, Florida imposed a temporary moratorium on executions.
After the Supreme Court agreed in September 2007 to hear the case, Michael Richard, 48, became the last person to be executed in the US just hours later. He had been convicted for the rape and murder of a woman 20 years earlier.
Around two-thirds of Americans favor the death penalty, according to the DPIC, in a country where 3,260 detainees are presently on death row.
In December, the northeastern state of New Jersey became the first state in 40 years to abolish the death penalty.