WASHINGTON (USA TODAY) -- The Supreme Court made it more difficult Tuesday for states to impose the death penalty on prisoners who claim an intellectual disability, marking the first time it has fine-tuned a landmark 2002 decision barring executions of the mentally retarded.
The court ruled that Florida must apply a margin of error to IQ tests administered to Freddie Lee Hall, 68, who killed a 21-year-old pregnant woman and a deputy sheriff in 1978. The state had argued that any test score above 70 made prisoners eligible for a death sentence, despite medical guidelines that permit scores to reach 75.
The 5-4 ruling by Justice Anthony Kennedy and the court's four liberal justices will affect a handful of states with similar policies among the 32 states with death penalties on the books. While very few prisoners with intellectual disabilities will be granted reprieves as a result, the ruling clarifies a delicate area of criminal law.
It also comes at a time when states' capital punishment procedures are under siege, beset by a shortage of drugs needed to perform lethal injections and rejuvenated efforts by disability rights groups to stop executions of prisoners with mental impairments. A federal appeals court last week blocked Texas from executing a death-row prisoner claiming intellectual disability.
"Florida's law contravenes our nation's commitment to dignity and its duty to teach human decency as the mark of a civilized world," Kennedy said. "The states are laboratories for experimentation, but those experiments may not deny the basic dignity the Constitution protects."
The case marked a return for the court to Atkins v. Virginia, its 2002 decision that executing people with intellectual disabilities violates their 8th Amendment rights against cruel and unusual punishment.
The key dispute ever since then has been who gets to define mental retardation, now referred to as intellectual disability -- states or medical professionals. The Supreme Court set a three-prong test that includes intellectual functioning, adaptive behavior and age of onset. But Florida doesn't consider the latter two prongs if the IQ score is above 70.
During oral argument in February, the court's liberal justices denounced the state's rigid cutoff, one that is shared by Alabama, Virginia and Kentucky. Several other states use similar criteria.
No one in Hall's precise situation has been executed in the 12 years since the high court prohibited the death penalty for people with intellectual disabilities. Only four other death-row residents in Florida and Alabama face similar predicaments.
But the court's ruling could have broad repercussions in the future by spelling out exactly what the justices meant when they prohibited executing the mentally retarded without defining specifically who is and who isn't.
The number of executions in the United States peaked at 98 in 1999 but dropped to 39 by last year, according to the Death Penalty Information Center. Twenty prisoners have been executed so far this year. From 1984 to 2001, 44 people with mental retardation were executed.
Since the Atkins ruling, several hundred claims of mental retardation have been filed by prisoners on death row, representing about 7% of all cases, according to John Blume, a Cornell University law professor. Slightly more than 100 sentences have been reduced as a result, a 28% success rate.