The American Civil Liberties Union and Nevada Coalition Against the Death Penalty have called on the Pardons Board to block Monday's scheduled execution of murderer William Castillo.
"We implore you to halt Monday's execution and delay any other executions in Nevada until the United States Supreme Court has issued a decision on the constitutionality of lethal injection," the letter states.
The Pardons Board consists of the members of the Nevada Supreme Court plus the attorney general, chaired by the governor.
The letter signed by ACLU Nevada President Richard Siegel and Nancy Hart, president of the coalition, said there is even precedent in Nevada for a stay. The board issued a stay in the Thomas Nevius case in 2001 until after the U.S. Supreme Court ruled on the constitutionality of executing mentally retarded offenders.
"Respect for law is best served by allowing the judicial system to fully adjudicate the constitutionality question before acting," they argued.
According to the letter, even Texas, which executes more inmates than any other state, has decided to wait while the high court reviews the Kentucky case charging that lethal injection is unconstitutionally cruel because the inmates are actually aware and in pain as they are dying.
Siegel said executions have been halted in at least 10 states because of those arguments. He said the method of lethal injection used in Nevada is substantially the same as that used in Kentucky.
"The state of Nevada should not be executing any of its prisoners, voluntary or not, while the U.S. Supreme Court is deciding whether the method used violates the constitution."
Gov. Jim Gibbons, who has sole authority to call a meeting of the Pardons Board, was in Hawaii attending the Republican Governors' Convention. Press Secretary Melissa Subbotin said there are no plans to stop the execution.