How low does an IQ have to be to avoid execution? Supreme Court won’t weigh in on Alabama case

The U.S. Supreme Court declined to intervene in an Alabama death penalty case on Thursday, effectively ending the state’s attempt to challenge a lower court's finding that death row inmate Joseph Smith is intellectually disabled. By choosing not to weigh in, the high court ensured that the existing ruling remains in place, keeping Smith ineligible for execution.

The Legal Stalemate

The case revolves around a long-standing legal battle over whether Alabama can proceed with the execution of Joseph Smith, who was convicted for his role in the 1997 robbery and fatal beating of Durk Van Dam in Mobile County. While Smith’s guilt in the incident—where Van Dam was robbed of power tools, cash, and his shoes—is not in question, the argument before the Supreme Court centered on the interpretation of intellectual disability and the legal thresholds for capital punishment.

Federal courts have repeatedly ruled that Smith is intellectually disabled, meeting the criteria established by the Supreme Court’s 2002 decision in Atkins, which prohibits the execution of intellectually disabled individuals. Despite this, Alabama Attorney General Steve Marshall’s office argued in early 2025 that Smith’s IQ exceeds the typical threshold, maintaining that he should not be exempt from the death penalty.

Justices Spar Over Ruling

The court's decision to dismiss the case as “improvidently granted” sparked sharp disagreement among the justices. Associate Justice Clarence Thomas penned a scathing dissent, arguing that the court should have allowed the execution to proceed. “No one contends that Smith is a common-law idiot,” Thomas wrote, asserting that Smith’s literacy and IQ scores place him above the standard markers for intellectual disability. He further suggested that the court should overturn the Atkins precedent entirely, claiming it has fostered nothing but “confusion and absurdity.”

In contrast, Associate Justice Sonia Sotomayor, joined by Associate Justice Ketanji Brown Jackson, authored a concurring opinion upholding the lower court's determination. Sotomayor defended the ruling, noting that the evidence for Smith’s intellectual disability is “correct, or, at the very least, plausible.” She also pushed back against the state's proposed methods for analyzing IQ, remarking during December’s oral arguments that Alabama appeared to be “making something wholesale up” regarding how to evaluate test scores.

Future Uncertainty

Associate Justice Samuel Alito, who joined Thomas in his dissent, expressed frustration with the court's inaction. He argued that by failing to provide clear rules for capital cases involving intellectual disability, the court leaves lower jurisdictions without necessary guidance. “Our silence on this issue leaves courts without direction on how to address a recurring situation,” Alito wrote.

As medical and psychological standards continue to evolve—with modern manuals placing the diagnostic range for intellectual disability between 65 and 75—the divide between state prosecution and federal standards remains stark. For now, however, the Supreme Court’s refusal to hear the appeal means the attempts to execute Joseph Smith will not move forward.