High court again blocks pending execution

WASHINGTON (CNN) –The Supreme Court has again blocked a scheduled execution, keeping in place a de facto moratorium on capital punishment while it considers the broader constitutional question over how lethal injection is administered.

The justices without comment Thursday delayed indefinitely the execution of James Harvey Callahan, who sits on Alabama's death row after a 1982 murder. The high court announcement came about an hour before he was scheduled to die at the Holman prison.

A federal appeals court in Atlanta had lifted a previous stay of execution Wednesday, saying Callahan missed crucial deadlines to file briefs challenging the method of execution.

–From CNN Supreme Court Producer Bill Mears