By Lawrence Hurley
WASHINGTON (Reuters) - The Supreme Court on Friday agreed to review Oklahoma's controversial method of execution by lethal injection, taking up a case brought by three death row inmates who accuse the state of violating the U.S. Constitution's ban on cruel and unusual punishment.
The high court just last week allowed the execution of a convicted killer in Oklahoma over the objection of its four liberal members.
The three-drug process used by Oklahoma prison officials has been under scrutiny since the April 2014 botched execution of convicted murderer Clayton Lockett. He could be seen twisting on the gurney after death chamber staff failed to place the IV properly.
The inmates challenging the state's procedures argue the sedative used by Oklahoma, midazolam, cannot achieve the level of unconsciousness required for surgery, making it unsuitable for executions.
The case draws fresh attention to the ongoing debate over whether the death penalty should continue in the United States at a time when most developed countries have abandoned it.
The Death Penalty Information Center, which compiles execution statistics, says only seven of the 32 states that still have the death penalty on the books executed inmates in 2014, with most coming in just three states: Texas, Missouri and Florida. The group also says the number of executed inmates has hit a 20-year low.
The Supreme Court case directly affects only Oklahoma. But Florida uses a similar protocol so death row inmates there may seek stays based on the pending case.
On Jan. 15, the high court on a 5-4 vote declined to halt Oklahoma's execution of Charles Warner, convicted of raping and murdering an 11-month-old baby.
Although five votes are needed to grant a stay application, only four are required for the court to take up a case.
The inmates say Oklahoma's three-drug protocol can cause extreme pain, violating the Constitution's Eighth Amendment prohibition on cruel and unusual punishment.
After Lockett's execution, Oklahoma revised its protocols by increasing the amount of midazolam used to render an inmate unconscious. Lower courts endorsed the change, as did the divided Supreme Court.
Justice Sonia Sotomayor, one of the liberals who dissented in Warner's case, wrote an opinion at the time saying she was “deeply troubled by this evidence suggesting that midazolam cannot be constitutionally used as the first drug in a three-drug lethal injection protocol.”
But the fact that none of the court's five conservatives, including regular swing vote Anthony Kennedy, voted to grant the stay application suggests the inmates face an uphill battle to win their case.
The inmates want the court to decide whether its 2008 Baze v. Rees ruling upholding Kentucky's three-drug execution protocol applies to Oklahoma's procedures. The inmates' lawyers say Oklahoma's protocol is different, so the reasoning of the 2008 ruling should not apply.
"The drug protocol used in Oklahoma is not capable of producing a humane execution, even if it is administered properly," said Dale Baich, an attorney for the inmates.
Oklahoma Attorney General Scott Pruitt said, "We will continue to defend the constitutionality of this protocol in order to preserve (the Department of Corrections') ability to proceed with the sentences that were given to each inmate by a jury of their peers."
The inmates are Richard Glossip, John Grant and Benjamin Cole. Glossip, who arranged for his employer to be beaten to death, is scheduled to be executed on Jan. 29. Grant, who stabbed a correctional worker to death, is due to be executed on Feb. 19. Cole, convicted of killing his 9-month-old daughter, is scheduled for execution on March 5.
The case will be argued in April, with a decision due by the end of June.
(Reporting by Lawrence Hurley; Editing by Will Dunham)