Although the court gave no reason for its order, Mr. Turner, convicted of murdering his adoptive parents in 1998, had appealed to the court after it agreed Tuesday to consider the constitutionality of lethal injection, the most commonly used method of execution in the United States.

Several legal experts said the Supreme Court reprieve would be seen by most states as a signal to halt all executions until the court determined, probably some time next year, whether the current chemical formulation used for lethal injections amounts to cruel and unusual punishment barred by the Eighth Amendment.

Eleven states had halted executions for that reason. On Thursday, Alabama stayed an execution for 45 days to come up with a new formula.

“There is a momentum quality to this,” said Douglas A. Berman, a law professor at Ohio State University who has a blog, Sentencing Law and Policy. “Not only the Supreme Court granting the stay, but also the Alabama governor doing a reprieve that is likely to lead to other states with executions on the horizon waiting to see what the Supreme Court does. I’ll be surprised if many, and arguably if any states other than Texas, go through with executions this year.”

On his blog on Friday, Professor Berman predicted that there would be few if any executions in the country for the next 9 to 18 months, while the court deliberates and, later, as lower courts parse the meaning of its eventual ruling.