Hall's lawyers argued that only in five states - Florida, Alabama, Idaho, Kentucky and Virginia - have state courts held that inmates with IQs higher than 70 cannot be considered mentally disabled. Even in Idaho, the ruling appears to give judges some leeway, Hall's lawyers said.

Hall's case has bounced around the Florida courts for decades.

In 1989, the state Supreme Court threw out Hall's original death penalty and ordered a new sentencing hearing. A judge then resentenced Hall to death but declared that Hall was mentally disabled. That took place before the 2002 U.S. Supreme Court ruling that said executing a mentally disabled inmate violates the Eighth Amendment's ban on cruel and unusual punishment, and before Florida passed a law setting the IQ limit.

The Florida Supreme Court's most recent ruling upholding Hall's death sentence was by a 4-2 vote.

It included a dissent by Justice James Perry that noted that the testing below 70 is no guarantee of escape from the death penalty. Perry said the state court has upheld death sentences for inmates with IQs below 70 if other evidence indicates they are not mentally disabled. In one case, the inmate was able to obtain a GED diploma and live independently, Perry said. In another, the prisoner could copy letters written by others, sign his own name and work as a cook, garbage collector and dish washer, he said.

The case is Hall v. Florida, 12-10882.