572 U.S. 701 (2014)
On February 21, 1978, Freddie Lee Hall and his accomplice Mark Ruffin kidnapped, beat, raped, and murdered Karol Hurst, a pregnant 21-year-old newlywed.1 Afterward Hall and Ruffin drove to a convenience store they planned to rob and killed Lonnie Coburn, a sheriff’s deputy who attempted to apprehend them.2 Hall received the death penalty for both murders, although his sentence for the Coburn murder was later reduced on account of insufficient evidence of premeditation.3
When Hall was first sentenced, this Court had not yet ruled that the Eighth Amendment prohibits States from imposing the death penalty on persons with intellectual disability.4 After this Court held that capital defendants must be permitted to present nonstatutory mitigating evidence in death penalty proceedings, Hall was resentenced.5 Hall then presented substantial and unchallenged evidence of intellectual disability, including school records in which his teachers identified him on numerous occasions as mentally retarded, testimony from his prior lawyer that he could not understand anything Hall said, and testimony from medical clinicians that Hall was significantly retarded and had levels of understanding typically seen with toddlers.6 Hall’s siblings testified that there was something very wrong with him as a child, that he was slow with speech and slow to learn, and that he walked and talked long after his other brothers and sisters.7 The sentencing court found substantial evidence that Hall had been mentally retarded his entire life yet still imposed a death sentence, which the Florida Supreme Court affirmed.8
In 2002, after this Court ruled that the Eighth Amendment prohibited the execution of persons with intellectual disability, Hall filed a motion claiming that he had intellectual disability and could not be executed.9 More than five years later, Florida held a hearing to consider Hall’s motion.10 Hall again presented evidence of intellectual disability, including an IQ test score of 71.11 Hall had received nine IQ evaluations in 40 years, with scores ranging from 60 to 80, but the sentencing court excluded the two scores below 70 for evidentiary reasons, leaving only scores between 71 and 80.12 In response, Florida argued that Hall could not be found intellectually disabled because Florida law requires that, as a threshold matter, Hall show an IQ test score of 70 or below before presenting any additional evidence of his intellectual disability.13
The Florida Supreme Court rejected Hall’s appeal and held that Florida’s 70-point threshold was constitutional.14 This Court granted certiorari.15
Whether the Eighth and Fourteenth Amendments permit a State to require that a capital defendant establish an IQ score of 70 or below before presenting additional evidence of intellectual disability?16
The Eighth Amendment prohibits execution of persons with intellectual disability because no legitimate penological purpose is served and such persons face special risks in the trial process.17 When a defendant's IQ test score falls within the acknowledged margin of error on the test, the defendant must be permitted to present additional evidence of intellectual disability, including evidence regarding deficits in adaptive functioning drawn from medical histories, behavioral records, school reports, and testimony about past behavior and family circumstances.18 A state rule that treats an IQ score above 70 as conclusive and bars all further inquiry violates the Eighth Amendment.19
No. Hall presented an IQ test score of 71 along with nine evaluations over forty years that ranged from 60 to 80, though only scores between 71 and 80 remained after exclusion of two lower scores.20 This 71 falls within the standard error of measurement that professionals recognize as inherent in IQ testing.21 The established facts detail substantial evidence of adaptive deficits, including school records repeatedly identifying Hall as mentally retarded, prior counsel's testimony that he could not understand anything Hall said, medical clinicians' descriptions of understanding levels comparable to toddlers, siblings' accounts of developmental delays in speech and learning, and the sentencing court's own finding of substantial evidence that Hall had been mentally retarded his entire life.22 Florida's rule, as applied, required a strict threshold of 70 before any of this adaptive-functioning evidence could be considered and therefore foreclosed the inquiry the Eighth Amendment requires.23
Florida's strict 70-point threshold, as interpreted by the Florida Supreme Court, is unconstitutional under the Eighth and Fourteenth Amendments.24
Related opinions on this issue
Joined by Roberts, C. J., And Scalia And Thomas, Jj.
Justice Alito dissented on the ground that no national consensus exists against Florida's approach.25 He noted that at most ten death-penalty states do not require consideration of the standard error of measurement, twelve do require it, and nine have taken no definitive position, so the statistics do not establish a consensus.26 Alito argued that counting the nineteen non-death-penalty states is improper because their abolition of capital punishment says nothing about the proper method for identifying intellectual disability.27
He further contended that the majority improperly elevates the changing views of private professional associations over state legislative judgments, creating instability because those clinical definitions have been altered and sometimes rescinded in the past.28 Alito maintained that Florida's allowance of multiple IQ tests already accounts for measurement error and that the majority's rule improperly permits evidence of adaptive deficits to override a failure to prove significantly subaverage intellectual functioning.29