The U.S. Supreme Court considered Thursday whether to let Alabama execute a death row inmate who claims an intellectual disability combined with the state’s inattention cost him a chance to avoid lethal injection and choose a less “torturous,” yet untried, method.

The Alabama attorney general’s office asked the justices to lift a lower court order that blocked prison workers from putting to death Matthew Reeves, who was convicted of killing a driver who gave him a ride and then celebrating the man’s killing at a party with blood still on his hands.

The defense argued that the state, in asking the court to vacate an earlier ruling so it could execute Reeves, was improperly trying to challenge a decision it had lost repeatedly in lower courts.

Meanwhile, the state said it was preparing to execute Reeves, 43, by lethal injection at Holman Prison in case the court allowed it to go forward as scheduled at 6 p.m. CST.

The state previously asked the 11th U.S. Circuit Court of Appeals to lift a lower court injunction and allow the execution, but the panel on Wednesday refused and said a judge didn’t abuse his discretion in ruling that the state couldn’t execute Reeves by any method other than nitrogen hypoxia, which has never been used. Alabama appealed that decision, sending the case to the Supreme Court.