WASHINGTON — A closely divided Supreme Court on Tuesday struck down Florida’s strict IQ cutoff for determining a convicted criminal’s eligibility for the death penalty.In a 5-4 ruling, the court concluded that Florida’s rigid IQ threshold of 70 “disregards established medical practice” and creates the “unacceptable risk” that an inmate with intellectual disabilities might be executed, in violation of the Constitution.“Our society does not consider this strict cutoff as proper or humane,” Justice Anthony Kennedy wrote.Instead, Kennedy and the court’s four liberal justices concluded, Florida must consider IQ testing’s standard error of measurement, as well as other factors, in evaluating intellectual disability. This is already the practice in most of the nation’s other death-penalty states. Texas does not set a numerical IQ cutoff but applies seven factors that critics call “impressionistic” rather than scientific.“By failing to take into account the [standard error of measurement] and setting a strict cutoff at 70, Florida goes against the unanimous professional consensus,” Kennedy wrote. “The flaws in Florida’s law are the result of the inherent error in IQ tests themselves.”Conservative Justice Samuel Alito, writing for the dissenters, noted that nine other states besides Florida effectively impose strict IQ cutoffs of 70 when determining eligibility for the death penalty. These other states also might face new pressure to change their practices.“It is quite wrong for the court to proclaim that ‘the vast majority of states’ have rejected Florida’s approach,” Alito wrote. “The states have adopted a multitude of approaches to a very difficult question.”The state tally is important to justices on all sides, because it can measure what the Supreme Court calls the “evolving standards of decency” concerning criminal penalties and punishments. Citing these evolving standards, for instance, the high court in 2005 banned the death penalty for those who commit crimes under the age of 18.Kennedy wrote the 2005 opinion, as well.Freddie Lee Hall, the 68-year-old inmate at the heart of the case decided Tuesday, has been on the state’s death row since 1978. He and an accomplice were convicted of killing a 21-year-old pregnant woman and a Hernando County deputy sheriff.The 16th of 17 children, Hall was “tortured by his mother and abused by his neighbors,” according to a 1993 dissenting opinion in the Florida Supreme Court. Hall was “functionally illiterate and has the short-term memory of a first-grader,” the dissenting opinion observed.In nine separate IQ tests conducted throughout the years, Hall’s scores ranged from 60 to 80. Before one crucial hearing, he scored a 71.The Supreme Court has previously decided, in the 2002 case Atkins v. Virginia, that executing those variously called mentally retarded or intellectually disabled violates the Eighth Amendment’s prohibition against cruel and unusual punishment. The court left the definition up to individual states.“No legitimate penological purpose is served by executing a person with intellectual disability,” Kennedy wrote in the decision issued Tuesday. “To impose the harshest of punishments on an intellectually disabled person violates his or her inherent dignity as a human being.”IQ test scoresFlorida imposes a three-part test, which under a state court ruling effectively starts with a rigid requirement that the inmate score 70 or below on the IQ test. If the inmate scores below the cutoff number, the state will also assess for “deficits in adaptive behavior” and an onset before age 18.Medical professionals, Kennedy stressed Tuesday, consider an IQ test score to represent a range rather a fixed point. Test scores may fluctuate from day to day, depending on the testing environment, the test-taker’s health, previous practice or other reasons.The term “standard error of measurement” reflects the range that a single test score may represent. A score of 71, for instance, is generally considered to reflect a range of 66 to 76.“An IQ score is an approximation, not a final and infallible assessment of intellectual functioning,” Kennedy wrote.Texas’ Briseno guidelinesSince the Atkins ruling, the Texas Legislature has repeatedly defeated proposals, many authored by state Sen. Rodney Ellis, D-Houston, to define critieria for intellectual disability.According to the Texas Tribune, in 2004, when Death Row inmate Jose Garcia Briseño’s case came before the Texas Court of Criminal Appeals, the nine judges were without legislative guidance and developed their own standards. Lawyers for Briseño, who remains on Death Row, argued that he was mentally retarded and should not face execution for the 1991 murder of a Dimmit County sheriff’s deputy. The court rejected those arguments and in the process developed the so-called Briseño factors that are used now to determine whether Texas defendants are eligible for the death penalty. The court’s three-part definition requires the convicted inmate to have below average intellectual function, to lack adaptive behavior skills and to have had those problems prior to age 18. Lawyers for at least 90 Texas Death Row inmates have brought so-called Atkins claims before the courts, arguing that their clients’ limited cognitive functioning exempted them from execution. Of those, 14 have been deemed mentally retarded and their sentences commuted to life in prison. Among those who have been executed, one from Tarrant County was Michael Hall, convicted in the 1988 slaying of Amy Robinson of Arlington. His IQ test scores ranged from 64 to 72. Federal appeals courts up to the Supreme Court rejected his appeals, and he was executed on Feb. 15, 2011.Last week, the Supreme Court halted the execution of Robert James Campbell of Houston to allow his attorney to pursue an appeal that Texas Department of Criminal Justice officials failed to turn over three intelligence tests from Campbell’s earlier imprisonment that bolstered his claims of low IQ. His attorney contends that Campbell has an IQ of 69. This report includes material from The Texas Tribune and the Star-Telegram archives.