SCOTUS to Determine Definition of Intellectual Disability

Takeaways

• The Supreme Court is reviewing a death penalty case, Hamm v. Smith, to decide how “intellectual disability” (ID) is legally defined.
• The definition matters because the Supreme Court previously ruled that people with an intellectual disability cannot be executed.
• The core issue is whether courts should rely only on a single, lowest possible IQ test score (after adjusting for the test’s known margin of error), or if they must take a holistic approach.
• A holistic approach includes all of the person’s IQ scores plus expert testimony on their ability to cope with daily life (adaptive behavior), such as social skills and independent living.
• The Court’s decision will not only affect the inmate in this case but will also provide a clear, lasting standard for all future death penalty cases involving claims of ID.
• The ruling could also influence how ID is defined in other legal areas, such as qualifying for disability benefits (Social Security) and educational services.

The United States Supreme Court could soon give greater clarity to how intellectual disability is determined. On December 10, 2025, the Court will hear oral arguments in Hamm v. Smith, a case that involves an Alabama death-row inmate who may escape the death sentence depending on whether he is found to be intellectually disabled. At issue is whether IQ test scores alone are sufficient when determining if a person is intellectually disabled — a designation that under U.S. law can make someone ineligible for the death penalty.

What This Case Is About

This case involves Joseph Clifton Smith, who was convicted in Alabama of a 1997 murder and sentenced to death. In postconviction proceedings, Smith’s legal team argued that he is intellectually disabled, which, under the 2002 Supreme Court decision Atkins v. Virginia, means he is not allowed to be executed.

Smith has taken five full-scale IQ tests, with scores ranging from 72 to 78. Because IQ tests are not exact, the lowest of his scores (72) could theoretically reflect a “true” IQ as low as 69, once the standard error of measurement is accounted for. That estimate played a big role in a lower court judge’s decision to vacate Smith’s death sentence.

The U.S. Court of Appeals for the Eleventh Circuit affirmed the lower court’s decision, using what it described as a holistic approach. It considered all five IQ scores plus expert testimony about Smith’s difficulties in self-direction, social and interpersonal skills, independent home living, education, and other adaptive deficits.

Why the Supreme Court Is Involved

When Smith’s case first reached the Supreme Court in 2024, the justices did not immediately rule on it. Instead, they vacated (set aside) the Eleventh Circuit’s ruling and sent it back for clarification, noting that the lower court’s opinion was ambiguous. On one reading, it seemed to treat Smith’s lowest possible IQ score (69) as decisive. On another, it suggested a more balanced, evidence-wide analysis.

After the remand, the Eleventh Circuit made clear it was relying on the holistic approach, which included not just the low-end IQ estimate, but all his test results and expert views on his functioning. Alabama then appealed again, asking the Supreme Court to clarify what standard should apply when someone submits multiple IQ scores in a death-penalty case.

What’s at Stake

This case could determine more than just Smith’s life.

Legal Clarity for Capital Cases

If the Supreme Court endorses a holistic standard, courts would be required to consider the full picture — all IQ scores, not just one number, plus how a person functions in daily life. But if the Court instead rules that the lowest possible score after adjusting for error should decide, it could set a stricter rule that makes it harder for some people to qualify as intellectually disabled.

Effects on People With Intellectual Disabilities

For people with borderline or variable IQ test results, this could be a life-or-death decision. A ruling that supports holistic evaluation would validate expert testimony about adaptive behavior (how someone copes, learns, interacts), not just raw test scores. That matters for fairness and dignity, since intellectual disability is more than just a number.

Broader Implications

Though this case directly concerns the death penalty, how the courts treat IQ testing could influence other areas, such as criminal sentencing, disability benefits, and eligibility for services.

Science Meets Law

The case is also a reminder of the limits of standardized testing. IQ tests have known margins of error. Courts must grapple with statistical uncertainty and decide how much weight to give to that uncertainty when making life-altering decisions.

Why It Matters Now

The Supreme Court has recognized that how intellectual disability is defined affects more areas of life than just who is exempt from the death penalty. The outcome of this case could determine how individuals are classified as disabled and are therefore eligible for Social Security benefits, extra educational services, and other accommodations.

Additional Reading

For additional reading on topics related to individuals with disabilities, check out the following articles:

• Intellectual and Developmental Disability: What Is an IDD?
• Bill of Rights for Airline Passengers With Disabilities
• Rideshare Apps: Pros and Cons for People With Disabilities
• People With Disabilities Could Save More Under Proposed Bill
• SSDI for Adults With Disabilities When a Parent Retires
• Employment Up for People With Disabilities But Gaps Remain
• Estate Planning for Parents of Children With Mental Illness