Stevenson, who represents Callahan, said he expects both Alabama execution dates to be called off.
"There is every indication these will be stayed. The question is by whom and when?" he said.
The U.S. Supreme Court has allowed only one execution to be carried out since it agreed to hear the Kentucky case. That execution occurred in Texas on Sept. 25, the same day the court agreed to take the Kentucky case.
Assistant Attorney General Clay Crenshaw said the U.S. Supreme Court has not ordered a halt to all executions.
"Hopefully the Supreme Court will allow these to go forward. You are talking about cases that have been litigated over 20 years," Crenshaw said.
Arthur had been scheduled to die Sept. 27, but Gov. Bob Riley delayed the execution temporarily to allow the state Department of Corrections to change its execution procedures. The new procedures provide more checks to make sure an inmate is unconscious before receiving drugs to stop the lungs and heart.
Arthur, 65, who has maintained his innocence, was sentenced to death for the Feb. 1, 1982 killing of Troy Wicker, 35, of Muscle Shoals. The victim's wife, Judy Wicker, testified she had sex with Arthur and paid him $10,000 to kill her husband, who was shot in the face as he lay in bed.
At the time of his arrest for the Wicker killing, Arthur was serving a sentence at a prison work release center for an earlier slaying.
Callahan, 60, was was convicted of the abduction and asphyxiation of Jacksonville State University student Rebecca Suzanne Howell, who disappeared from a Calhoun County washateria on Feb. 4, 1982.
Callahan and death row inmate Willie McNair have filed court suits challenging Alabama's legal injection procedures as unconstitutionally cruel. U.S. District Judge Keith Watkins has combined the two cases and tentatively scheduled them for trial the last week of November.
