World & Nation

Supreme Court says IQ cannot determine mental fitness in capital cases

Anthony Kennedy
“Intellectual disability is a condition, not a number,” said Justice Anthony M. Kennedy.
(Matt Slocum / Associated Press)

The Supreme Court put new limits on the death penalty Tuesday, deciding that states may not use a “rigid rule” that denies leniency to defendants with severe mental disabilities simply because they score 70 or above on an IQ test.

“Intellectual disability is a condition, not a number,” said Justice Anthony M. Kennedy. He advised judges to view IQ test scores with “studied skepticism” and instead look closely at how the convict had functioned throughout his life prior to the crime.

The 5-4 decision gives new hope to convicted murderers in Florida and at least eight other states that have relied heavily on IQ scores to decide who should be spared from capital punishment.

The American Psychological Assn. applauded the decision. “We are pleased that a majority of the court agreed that Florida’s use of a fixed cutoff score ... is based on a fundamental misunderstanding of how to interpret IQ scores,” said Nathalie Gilfoyle, the group’s general counsel. She said there was a scientific consensus across professional organizations that an individual’s “adaptive functioning” must be considered along with test scores.


It was the high court’s first decision on the issue since 2002, when it barred the death penalty for those deemed “mentally retarded.” The 2002 ruling did not precisely define who qualified for the exemption. The justices had reasoned at the time that although capital punishment was constitutional, it should be limited to the most deserving.

Because people with mental disabilities may act impulsively and without considering the consequences, it would be “cruel and unusual punishment” to put them to death, the court ruled in 2002. The court noted that an IQ score below 70 was a common sign of intellectual disability.

Since then, Florida, Virginia, Kentucky and Alabama have decided that any convict who scores at least 70 on an IQ test does not have an intellectual disability. Five other states — Arizona, Delaware, Kansas, North Carolina and Washington — appear to use a “bright-line cutoff” based on an IQ test, Kennedy said in the latest ruling.

Kennedy also noted a trend among states to move away from the death penalty. In the last decade, five states — Connecticut, Illinois, Maryland, New Jersey and New Mexico — abolished capital punishment. New York’s death penalty was struck down by a state court in June 2004. Other states, including California, have maintained the death penalty but do not set an IQ cutoff score for deciding who should be spared.


In Tuesday’s decision, Kennedy and the court’s four liberal justices set out what they consider to be the flaws in Florida’s approach to deciding whether a defendant suffers from an intellectual disability.

Freddie Lee Hall was judged by schoolteachers and friends to be severely “retarded” as a child and as a young man. He had difficulty speaking and learning words. He was also horribly abused by his mother because he was “slow.” She beat him with a belt, poked him with sticks, strapped him to his bed at night with a rope thrown over a rafter, and in one incident cited by the court, put him in a sack and swung it over a fire.

In 1978, Hall and another man kidnapped and killed a young woman and then a shot a policeman outside a convenience store. Although a judge agreed Hall “had been mentally retarded his entire life,” he was sentenced to death.

After the Supreme Court’s 2002 ruling, Hall’s death sentence was reconsidered. But judges noted that he had taken several IQ tests and had achieved scores of 71 and 80 at different times and, therefore, could not qualify as “retarded.”

In Hall vs. Florida, the justices set aside this definition.

“This rigid rule, the court now holds, creates an unacceptable risk that persons with an intellectual disability will be executed, and thus is unconstitutional,” Kennedy said. Justices Ruth Bader Ginsburg, Stephen G. Breyer, Sonia Sotomayor and Elena Kagan agreed.

In dissent, Justice Samuel A. Alito Jr. faulted the majority for a “new and unwise turn” in the law by relying on “private professional associations” to establish constitutional values.

In the past, he said, the court had looked to states and to public opinion to judge American values. “Now the court strikes down a state law based on the evolving standards of professional societies, most notably the American Psychiatric Assn.,” he said. Chief Justice John G. Roberts Jr. and Justices Antonin Scalia and Clarence Thomas agreed with him.


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