Hamm v. Smith Explained: Can IQ Scores Alone Determine Intellectual Disability in Death Penalty Cases?
In Hamm v. Smith, the U.S. Supreme Court dismissed a closely watched death penalty case about how courts should evaluate intellectual disability. The case asked whether courts can consider multiple IQ test scores as part of a full clinical assessment when deciding whether a person is intellectually disabled and therefore protected from execution under the Eighth Amendment. In a 5-4 decision issued on May 21, 2026, the Court dismissed the case as “improvidently granted,” meaning the justices decided they shouldn’t have agreed to hear it in the first place. As a result, the Court didn’t answer the underlying question, leaving uncertainty about how courts should use multiple IQ scores in future death penalty cases involving intellectual disability.
Bottom line: The Supreme Court didn’t decide whether courts can rely on multiple IQ scores when determining intellectual disability in death penalty cases.
What is Hamm v. Smith about?
Before the Supreme Court dismissed the case, Hamm v. Smith asked an important question about how courts determine whether a person has intellectual disability in death penalty cases.
That question matters because the Supreme Court has already ruled that executing a person with an intellectual disability is unconstitutional. In Hamm v. Smith, the issue wasn’t whether that protection exists. It was how courts should apply it. More specifically, the case asked whether courts can consider multiple IQ test scores as part of a full clinical evaluation, or whether they should give too much weight to the numbers alone.
The Court agreed to review “whether and how courts may consider the cumulative effect of multiple IQ scores in assessing an Atkins claim.”
Can a state execute a person with an intellectual disability?
No. In Atkins v. Virginia, the Supreme Court ruled that the Eighth Amendment’s ban on cruel and unusual punishment prohibits the execution of people with intellectual disability. Later decisions reinforced that courts cannot use an overly rigid or outdated approach when deciding whether someone has an intellectual disability. In Hall v. Florida in 2014, the Court rejected a strict cutoff based only on IQ test scores. In Moore v. Texas in 2017, the Court ruled that courts must use clinical standards, not stereotypes or non-clinical assumptions.
Those rulings are consistent with how intellectual disability is actually diagnosed by experts. It’s not determined by an IQ test alone. Clinicians look at the whole picture, including intellectual functioning, adaptive functioning, and whether the disability began during the developmental period. IQ tests can be part of that picture, but they aren’t the whole picture.
A person may take multiple IQ tests throughout their life. Those scores can be helpful, but they don’t replace clinical judgment. Different tests can produce somewhat different results, and an outlier score doesn’t automatically tell the full story. Courts should look at all the relevant evidence, including how a person functions in daily life.
How did Hamm v. Smith reach the Supreme Court?
Joseph Smith was convicted of murder in Alabama in 1997, before the Supreme Court’s decision in Atkins v. Virginia. After Atkins, Mr. Smith sought post-conviction relief, arguing that he has intellectual disability and cannot be executed.
In 2022, the U.S. Court of Appeals for the Eleventh Circuit ruled in his favor. The court considered Mr. Smith’s history of adaptive deficits dating back to grade school, where he was evaluated for special education services. It also considered five IQ tests, four of which had scores in the low-to-mid 70s. The court concluded that the evidence, viewed together, supported a finding of intellectual disability.
Alabama appealed to the Supreme Court. In November 2024, the Supreme Court sent the case back down to the Eleventh Circuit and asked it to clarify how it used Mr. Smith’s multiple IQ scores. The Eleventh Circuit said it had looked holistically at his scores, not by relying on the lowest score alone. Alabama appealed again, and in June 2025, the Supreme Court agreed to hear the case on a limited question about whether and how courts may consider multiple IQ test scores in an Atkins claim.
What did the Supreme Court decide in Hamm v. Smith?
In a 5-4 vote, the Supreme Court dismissed Hamm v. Smith instead of deciding the question it had agreed to review. The Court’s full order was one sentence: it dismissed the case as “improvidently granted,” meaning the justices concluded they shouldn’t have taken it in the first place. As a result, the lower court’s ruling stands, and Joseph Smith remains protected from execution under the Eighth Amendment.
Justice Sotomayor, joined by Justice Jackson, wrote separately to explain why dismissal was appropriate. She said the case wasn’t the right vehicle for resolving how courts should evaluate multiple IQ scores in death penalty cases. In her view, the parties agreed on an important point: courts can consider multiple IQ scores when determining whether a person has an intellectual disability. She also explained that the lower courts hadn’t actually decided the broader legal rule Alabama wanted the Supreme Court to announce. Because of that, she concluded the Court couldn’t properly answer that question here.
Justice Sotomayor also underscored a key point The Arc raised in its amicus brief: intellectual disability cannot be reduced to IQ scores alone. Citing disability and clinical experts, she wrote that “IQ test scores cannot stand alone” and must be considered alongside other evidence, including adaptive functioning and the person’s day-to-day intellectual functioning.
Justice Thomas dissented, arguing that Atkins v. Virginia was wrongly decided.
Justice Alito, joined by Chief Justice Roberts, Justice Gorsuch, and Justice Thomas, also dissented, arguing that the Court should have decided this case and given lower courts more guidance on how to use multiple IQ tests going forward.
What is The Arc’s view on intellectual disability and the death penalty?
The Arc’s position is clear: no person with intellectual disability should be executed, and states must use fair, accurate procedures that follow accepted clinical standards when deciding whether a person has an intellectual disability. Here’s more from our position statement on the criminal justice system:
When death penalty is an issue, individuals with intellectual disability… must: Continue to be exempt from the death penalty because existing case-by-case determinations of competence to stand trial, criminal responsibility, and mitigating factors at sentencing have proved insufficient to protect the rights of individuals with intellectual disability; Have access to expert witnesses and professionals who are knowledgeable about, as well as trained and experienced in, intellectual disability and who can accurately determine the presence and effects of intellectual disability; and [h]ave their intellectual disability determined by state procedures that are accurate… state procedures must be consistent with the national standards on making an intellectual disability determination and ensure that people with intellectual disability are not executed.
Since Atkins v. Virginia, The Arc has filed amicus briefs in every U.S. Supreme Court case involving the death penalty and intellectual disability, including Hamm v. Smith. In this case, The Arc argued that IQ tests have a built-in margin of error and cannot replace clinical judgment. Multiple IQ scores can make the analysis more complicated, especially when one score appears to be an outlier.
That’s why courts must look beyond numbers alone and consider the full clinical record, including adaptive functioning and other evidence of intellectual disability.
Why Hamm v. Smith matters for people with disabilities
This case matters because it’s about whether courts will follow science and accepted clinical standards when deciding who is protected from execution.
Intellectual disability is a lifelong condition. It cannot be reduced to a single IQ score. Experts have made clear that diagnosis requires a full evaluation, including intellectual functioning, adaptive functioning, and other evidence over time.
People with intellectual disability are at greater risk of being targeted, pressured, wrongfully convicted, and failed by the criminal legal system. Without fair, accurate, science-based standards, lives are at risk.
This case isn’t about excusing violent crime. People with intellectual disability can still be held accountable under the law. But the Constitution draws a clear line: people with intellectual disability cannot be executed.
Although the Supreme Court dismissed Hamm v. Smith without answering the question it agreed to review, existing constitutional protections remain in place.
Where can I learn more about Hamm v. Smith?
The Arc’s Hamm v. Smith Case Page
Hamm v. Smith FAQ: Intellectual Disability, IQ Scores, and the Death Penalty
Can a person with an intellectual disability be executed?
No. The Supreme Court ruled in Atkins v. Virginia that the Constitution prohibits executing people with intellectual disability.
What is Hamm v. Smith about?
The case asked whether courts can solely consider multiple IQ scores when deciding whether a person has an intellectual disability in a death penalty case.
What did the Supreme Court decide in Hamm v. Smith?
In a 5-4 decision on May 21, 2026, the Court dismissed the case as “improvidently granted,” meaning the justices decided they should not have taken it in the first place.
Why did the Supreme Court dismiss Hamm v. Smith?
A majority of the justices concluded this wasn’t the right case to resolve a broader rule about how courts should weigh multiple IQ scores. Justice Sotomayor wrote that the question Alabama wanted answered had not been properly decided in the lower courts.
Did the Supreme Court’s dismissal of Hamm v. Smith change the rule that people with intellectual disability cannot be executed?
No. The Supreme Court did not overturn Atkins v. Virginia. The constitutional rule remains the same: people with intellectual disability cannot be executed.
Why are IQ scores not enough by themselves?
Because intellectual disability is diagnosed using a full clinical assessment, not one number alone. Courts and clinicians must also consider adaptive functioning and other evidence.
Written by: Evan Monod, Staff Attorney for The Arc of the United States
Melanie from West Virginia knows this better than most. Her daughter, Kaycee, is 22 years old and full of hope for her future. But getting to this point was not easy. Melanie remembers the years before HCBS, when every day felt like a crisis. As she explains, “Before Kaycee had access to Medicaid and the IDD Waiver, our family was in constant crisis. She needed step-by-step support for daily life… We were doing everything we could, but it was not enough.”
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