By Lawrence Hurley
WASHINGTON (Reuters) - U.S. Chief Justice John Roberts provided the pivotal fifth vote on the Supreme Court to block the scheduled execution in Alabama of a 74-year-old man convicted in the 1982 shooting death of his girlfriend's husband.
Roberts said in a brief order issued late on Thursday that his action was a "courtesy" to four justices on the eight-member court who favored putting on hold the lethal injection execution of death row inmate Thomas Douglas Arthur.
The order did not say which justices voted for the stay of execution aside from Roberts, but noted that his fellow conservatives Samuel Alito and Clarence Thomas opposed it. The court is split with four liberals and four conservatives and has remained one justice short since the February death of conservative Antonin Scalia.
"I do not believe that this application meets our ordinary criteria for a stay," Roberts wrote. " ... The claims set out in the application are purely fact-specific, dependent on contested interpretations of state law, insulated from our review by alternative holdings below, or some combination of the three."
But Roberts, who has a record of supporting the death penalty, said he backed the stay so his colleagues can "more fully consider the suitability of this case for review."
Roberts' vote followed a similar action in August by liberal Justice Stephen Breyer to provide a "courtesy vote" when the court blocked a transgender student who was born female but now identifies as male from using the boys' bathroom at his Virginia high school while litigation continues.
The court on Oct. 28 subsequently agreed to hear the school district's appeal of a lower court's ruling favoring the student.
These two courtesy votes indicated the justices may be making a fresh effort to compromise as they navigate a difficult period and remain shorthanded for an extended time. The Republican-led U.S. Senate has refused to consider President Barack Obama's nominee to replace Scalia, appellate judge Merrick Garland, insisting that the winner of Tuesday's U.S. presidential election pitting Democrat Hillary Clinton against Republican Donald Trump should make the appointment.
Arthur has been on death row for more than three decades since being convicted of fatally shooting Troy Wicker as he slept. Prosecutors said Arthur's girlfriend, Judy Wicker, paid him $10,000 to kill her husband.
Arthur's attorneys have challenged the constitutionality of Alabama's lethal injection method of execution on the grounds that it is cruel and unusual punishment in violation of the U.S. Constitution's Eighth Amendment.
His lawyers have said lower courts are divided over how to interpret the Supreme Court's ruling in 2015 upholding Oklahoma's execution procedures. Their challenge focuses on part of that ruling that said an inmate contesting a method of execution based on the risk of severe pain has to show there is a "known and available alternative."
(Reporting by Lawrence Hurley; Editing by Will Dunham)