Supreme Court weighs in on execution, IQ tests

WASHINGTON – Twelve years after barring execution of the mentally disabled, the Supreme Court on Tuesday prohibited states in borderline cases from relying only on intelligence test scores to determine whether a death row inmate is eligible to be executed.

In a 5-4 decision that split the court’s liberal and conservative justices, the court said that Florida and a handful of other states must look beyond IQ scores when inmates test in the range of 70 to 75. IQ tests have a margin of error, and those inmates whose scores fall within the margin must be allowed to present other evidence of mental disability, Justice Anthony Kennedy said in his majority opinion.

A score of 70 is widely accepted as a marker of mental disability, but medical professionals say people who score as high as 75 can be considered intellectually disabled because of the test’s margin of error.

In 2002, the court said that executing mentally disabled inmates violates the Eighth Amendment prohibition on cruel and unusual punishment. But until Tuesday, the justices left to the states the determination of who is mentally disabled.