Law360 (May 21, 2026, 10:36 AM EDT) -- The U.S. Supreme Court on Thursday declined to rule on a case challenging limits on executing people whose IQ test results indicate they may have intellectual disabilities, leaving justices at odds months after oral arguments over how courts should weigh such test scores.

The justices dismissed the writ of certiorari "as improvidently granted" in a one-sentence per curiam opinion. Justice Sonia Sotomayor wrote a concurring opinion, joined by Justice Ketanji Brown Jackson. Justice Clarence Thomas wrote a dissenting opinion, and Justice Samuel Alito wrote another that was joined by Justice Thomas, and joined in part by Chief Justice John Roberts and Justice Neil Gorsuch. 

Justice Sotomayor said in her concurring opinion that the litigation in the lower courts did not focus on whether courts must use a specific methodology to evaluate multiple IQ test scores in determining a defendant's intellectual fitness for execution.

"Without the benefit of an evidentiary record or decisions below trained on the specific theories now advanced by the parties, this court rightly concludes that it should not provide more detailed guidance beyond what this court's cases have previously said," Justice Sotomayor wrote in her concurring opinion.

The dismissal leaves intact an Eleventh Circuit decision to vacate the death sentence of Joseph Clifton Smith, who was convicted of murder and sentenced to death in Alabama. The state brought the dispute to the justices, testing states' ability to set IQ-based limits for determining who can be sentenced to death under the high court's 2002 ruling in Atkins v. Virginia and progeny rulings, including Hall v. Florida  in 2014 and Moore v. Texas  in 2019. 

On Thursday, Justice Thomas argued in his dissent that Atkins should be overruled, writing that Atkins was an "egregious" case of granting relief based on an "unfounded Eighth Amendment claim." He added that the ruling "has denied the justice governments have given to murder victims from time immemorial."

Justice Alito, meanwhile, argued that the Eleventh Circuit's decision was flawed because it gave greater weight to Smith's lowest IQ score.

"At the very least, we should reverse the lower courts' erroneous analysis of Smith's scores and remand for a fresh consideration of his Atkins claim using any sound method," he wrote. "Even if our decision went no further, we would provide clarity and coherence to one aspect of our Atkins doctrine. Instead, the court shies away from its obligation to provide workable rules for capital cases. In doing so, the court disserves its own death-penalty jurisprudence, states' criminal-justice systems, lower courts, and victims of horrific murders."

To establish Smith's IQ, the lower courts relied on his scores on tests administered in 1979, 1982, 1998, 2014 and 2017 — scores that ranged from 74 to 78. Alabama argued that the lower courts did not appropriately analyze the multiple scores when they found that Smith's actual IQ could potentially be as low as 69 after adjusting for standard deviation.

An Alabama jury convicted Smith of murdering a man with a hammer and saw during a robbery in 1997, recommending a death sentence, according to Alabama's petition. The Alabama Court of Criminal Appeals affirmed his sentence, and the Alabama Supreme Court denied his petition for a writ of certiorari.

Initially, the U.S. Supreme Court also denied his petition. But Smith later filed a habeas petition that included a claim under Atkins. Alabama U.S. District Judge Callie Granade held a two-day evidentiary hearing on Smith's Atkins claim in 2015. In 2016, she took on senior status but remained on this case. The trial court denied Smith's habeas petition, but was reversed on appeal. In 2021, after another evidentiary hearing, the district court granted Smith's habeas petition and vacated his death sentence.

The judge found that Smith's scores placed him either in the range that's considered the border between disabled and nondisabled or "at the high end of the required significantly subaverage intellectual functioning." The judge also found that the decision of whether Smith was fit for execution would hinge on whether Smith had deficits in adaptive behavior and whether the problems surfaced during his developmental years.

Adaptive behavior is basically the ability to compensate for a disability and to execute basic tasks of life. The trial court cited Smith's ability to have a girlfriend and communicate with police as evidence that he displayed adaptive behavior. 

Smith had presented testimony from relatives and school records showing he had been in special education and struggled in basic math, reading and writing.

Alabama appealed to the Eleventh Circuit, arguing that the district court had wrongfully put the burden on the state to prove Smith was not intellectually disabled, rather than requiring him to prove he was, and that the district court made erroneous findings of fact without considering evidence he was not disabled. That court sided with Smith.

To succeed under Atkins, defendants must satisfy three prongs: They must have a significant intellectual impairment; they must have significant deficits in adaptive functioning; and their disabilities must have manifested during their developmental periods.

Alabama argued in its petition for a writ of certiorari that the Eleventh Circuit "eviscerated the most important prong of Atkins" by holding that even the possibility of a 70 IQ satisfies the requirement, and then "injected evidence of adaptive deficits into the first prong."

A group of 19 states that allow the death penalty filed an amicus brief supporting Alabama's position. Those states include: Idaho, Arkansas, Florida, Indiana, Kansas, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, and the Arizona state Legislature. The federal government filed its own amicus brief supporting Alabama.

On Thursday, Justice Sotomayor's concurrence backed the Eleventh Circuit's conclusion, saying it had taken a holistic approach that incorporated the test scores and expert testimony. She pointed out that the parties in the case agreed that there was no single approach to weighing multiple IQ test scores, and that the courts below did not meaningfully explore ways in which to do so.

However, she wrote that the issue could potentially be resolved in a future case.

"If a conflict among the states or lower courts emerges and a case properly presents the issue, it may be appropriate for this court to weigh in with more specific guidance about the permissible method or methods by which courts must analyze such scores," Justice Sotomayor wrote.

Alabama is represented by Steve Marshall, Edmund LaCour Jr., Robert Overing and Dylan Mauldin of the office of the Alabama attorney general.

Smith is represented by Seth Waxman of WilmerHale, and Christine Freeman and Kacey Keeton of the Federal Defenders for the Middle District of Alabama.

The case is Hamm v. Smith, case number 24-872, in the Supreme Court of the United States.

--Editing by Amy French.

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