WASHINGTON — A Floridian with an IQ as high as 75 may be diagnosed as mentally disabled and be eligible for help getting a job.
But on death row, the state says having an IQ higher than 70 categorically means an inmate is not mentally disabled and may be executed.
The Supreme Court barred states from executing mentally disabled inmates in 2002 but until now has left the determination of who is mentally disabled to the states.
In arguments Monday, 68-year-old Florida inmate Freddie Lee Hall is challenging the state’s use of a rigid IQ cutoff to determine mental disability.
Florida is among a few states that use a score of 70, as measured by IQ tests, as the threshold for concluding an inmate is not mentally disabled, even when other evidence indicates he is.
‘‘Simply put, IQ tests are not a perfect measure of a person’s intellectual ability,’’ Hall’s lawyers told the court in written arguments.
In nine tests administered between 1968 and 2008, Hall scored as low as 60 and as high as 80, with his most recent scores between 69 and 74, according to the state.
A judge in an earlier phase of the case concluded Hall ‘‘had been mentally retarded his entire life.’’ Psychiatrists and other medical professionals who examined him said he is mentally disabled.
As far back as the 1950s, Hall was considered ‘‘mentally retarded’’ — then the commonly accepted term for mental disability — according to school records submitted to the Supreme Court.
He was sentenced to death for murdering Karol Hurst, a 21-year-old pregnant woman who was abducted leaving a Florida grocery store in 1978.
Hall also has been convicted of killing a sheriff’s deputy and has been imprisoned for the past 35 years. He earlier served a prison term for assault with intent to commit rape and was on parole when he killed Hurst.
Florida’s regulatory code says individuals with IQs as high as 75 may be diagnosed as mildly intellectually disabled, potentially allowing them to receive state aid.