The Supreme Court on Thursday declined to overrule a federal judge’s order that blocked Alabama from executing an inmate accused of murder with nitrogen gas.Jeffery Lee was set to be executed at 6 p.m. Thursday local time under Alabama’s nitrogen hypoxia protocol, but the state chose not to proceed with the execution until the Supreme Court intervened.The high court voted 6-3 to leave the lower court’s stay against the method in place. Justices Clarence Thomas, Samuel Alito, and Neil Gorsuch represented the three votes that sided with Alabama. The court did not provide an explanation.

On Tuesday, U.S. District Judge Emily Marks declared nitrogen hypoxia unconstitutional one day after the U.S. Court of Appeals for the 11th Circuit reversed her initial decision from May in favor of the execution method. The federal appeals court reasoned there was a “substantial risk of serious harm” from nitrogen hypoxia.

Marks originally determined the protocol did not constitute cruel and unusual punishment, which is banned by the Eighth Amendment.

Alabama Attorney General Steve Marshall promptly appealed the federal judge’s second ruling to the Supreme Court this week. The appeal was ultimately unsuccessful.