IQ Scores and Death Sentences: Supreme Court’s Daring Silence

Sunlight streaming through prison cell bars.

By quietly sidestepping a key case on IQ scores and the death penalty, the Supreme Court just left life-and-death power in the hands of unelected experts and inconsistent state rules.

Story Snapshot

The Supreme Court declined to clarify what IQ level bars execution for intellectually disabled inmates, despite years of confusion in the lower courts.
Existing precedent rejects rigid IQ cutoffs but lets states keep wide discretion, creating a patchwork of justice across the country.
Professional groups push a “holistic” standard that leans heavily on expert judgment, not clear constitutional lines.
This drift risks both wrongful executions and endless appeals, while eroding public trust in equal justice under law.

How We Got Here: From Atkins to the New “IQ Question” the Court Just Dodged

Two decades ago, the Supreme Court held that executing people with intellectual disability violates the Eighth Amendment’s ban on cruel and unusual punishment, in a case called Atkins v. Virginia. That ruling left states room to define intellectual disability, and many turned to IQ tests as the first filter. Florida went furthest, adopting a hard rule that anyone scoring above 70 on an IQ test could not even present additional evidence of disability in a capital case.

In 2014, the Court struck down Florida’s rigid rule in Hall v. Florida, saying it treated an IQ score as “final and conclusive evidence” even though IQ testing is imprecise. The Court held that when a score falls within the test’s margin of error, defendants must be allowed to show adaptive deficits and other proof of disability.^[1] That decision was anchored in medical standards that treat intellectual disability as more than a single number, requiring a broader, clinical assessment.^[2]

What Hall Actually Says About IQ Cutoffs — And What It Does Not Say

Hall explicitly rejected a bright-line IQ threshold that blocks all further evidence, calling such a rigid rule an “unacceptable risk” that someone with intellectual disability will be executed. The Court required courts to consider adaptive functioning and expert testimony when scores fall into a borderline range, instead of using a single IQ score as a guillotine.^[2] At the same time, the decision did not ban states from using IQ numbers as part of their process, or from assigning the burden of proof to the inmate.

Legal summaries note that major professional bodies, like the American Psychological Association and American Psychiatric Association, support a diagnosis framework that allows intellectual disability even when IQ is slightly above 70, if adaptive functioning is seriously limited.^[2] That means medical experts favor multi-factor judgment calls, not simple thresholds. For conservatives who want clear laws and equal treatment, this move from firm rules toward flexible “holistic” assessments raises real concerns about transparency, consistency, and the potential for ideological bias in expert testimony.

Hamm v. Smith and the Rise of “Holistic” Death Penalty Fights

The recent case Hamm v. Smith put this tension back on the Supreme Court’s doorstep. The defendant, an Alabama man on death row, had multiple IQ scores ranging from the low seventies to the upper seventies, with some within the typical error range for intellectual disability. A federal district court reviewed his school records, work history, and everyday functioning, and concluded that his true intellectual level could fall low enough to qualify as disabled, vacating his death sentence.^[1]

The United States Court of Appeals for the Eleventh Circuit affirmed, emphasizing that courts should treat IQ scores as ranges and weigh them alongside adaptive deficits.^[1] Alabama argued that the best and most consistent scores showed IQ above 70, and that the state could reasonably insist that an offender prove his IQ is likely below that mark to escape execution.^[2] When the Supreme Court took up Hamm, it focused on how lower courts should weigh multiple IQ tests, not whether a particular number like 70 must control the outcome.

Supreme Court Caution or Evasion? What the “Duck” Means for Justice

Reporting on the Court’s handling of Hamm and similar disputes describes the justices as declining to set a new nationwide IQ threshold, instead leaving case-by-case balancing in place.^[3] That approach preserves Hall’s rejection of a rigid cutoff while avoiding a clear, updated rule for how multiple scores and expert opinions should be weighed. The Court’s caution may reflect a desire to respect state procedures, but it also leaves prosecutors, judges, and victims’ families with continued uncertainty.

Breaking: The U.S. Supreme Court struck down a stay of execution for Texas death row inmate Edward Busby on Thursday, clearing the way for his execution tonight amid concerns of his ineligibility due to intellectual disability. https://t.co/tB6dqZrut3

— Texas Tribune (@TexasTribune) May 14, 2026

For conservative readers, this is another example of an elite legal system drifting away from firm, knowable rules toward opaque expert-driven standards. On one side, we absolutely must guard against executing genuinely disabled individuals, consistent with basic human dignity and the Eighth Amendment. On the other, states need administrable rules so death sentences do not turn into endless, gameable IQ battles. By punting on a clearer standard, the Court risks undermining both goals instead of reinforcing a principled balance grounded in the Constitution.