The California Supreme Court has unanimously ruled that a defendant may be spared the death penalty because he is mentally deficient in one area, even if his IQ score falls in the normal range. The decision gives judges broader discretion to spare defendants from execution for reasons of mental impairment and clarifies a 2005 ruling that allowed those on death row to challenge their sentences on the grounds of mental retardation. The court ruled that trial courts may give greater weight to certain kinds of evidence than others because the legal definition of mental retardation does not rely on a fixed IQ score.

The California Supreme Court issued the ruling as it rejected a lower court decision that “full scale” IQ scores - composites of tests of various mental faculties - are the best way to measure intellectual functioning. The Justices ruled that courts may give greater weight to one measurement of IQ over another and that the best way to measure intellectual functioning may vary from case to case. It stated that the law should not dictate how to measure intellectual functioning.

“The question of how best to measure intellectual functioning in a given case is thus one of fact to be resolved in each case on the evidence, not by appellate promulgation of a new legal rule,” wrote Justice Katheryn Mickle Werdegar.

The California Supreme Court ruling could affect at least 28 people currently on California’s death row, and another 8 who are facing capital charges and are claiming mental retardation before trial.
(Los Angeles Times, April 13, 2007). See Mental Retardation.
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