Supreme Court weighs standards for executing inmates with intellectual disability

The Supreme Court confronted a core constitutional question on December 10 when justices considered whether Alabama may proceed with the execution of Joseph Clifton Smith, a man a lower court concluded is intellectually disabled and therefore exempt from capital punishment under long standing precedent. The case centers on how courts should weigh IQ test results and expert testimony when determining intellectual disability for death penalty eligibility.

Since the Court’s 2002 decision in Atkins v. Virginia, executing people with intellectual disability has been barred as cruel and unusual punishment. But significant uncertainty remains about the evidentiary standards states may apply. Lower courts typically evaluate three factors, intellectual functioning, adaptive behavior, and onset before adulthood, with IQ scores considered alongside clinical assessments. Alabama argues that its procedures are consistent with precedent, and the Trump administration has backed the state’s appeal in filings supporting a more constrained approach to disability claims.

At issue is whether rigid adherence to numerical IQ thresholds is required, or whether courts may discount scores that fall below clinical cutoffs when other evidence suggests functioning above those levels. The stakes are immediate for Mr. Smith, but they extend beyond one case. A ruling endorsing state latitude could narrow the scope of Atkins protections, while a decision reinforcing broad judicial deference to clinical assessments would likely make successful challenges to death sentences on disability grounds more common.

The ruling could also have measurable policy and budgetary consequences. Capital prosecutions and death row litigation are among the most resource intensive elements of state criminal justice systems. Research over many years has shown that capital cases generate higher trial and appeals costs than comparable noncapital cases because of expanded motions practice and prolonged postconviction review. A legal environment that produces more disability hearings and extended litigation would tend to increase fiscal pressures on state courts and corrections departments, already grappling with competing demands for Medicaid, education, and infrastructure spending.

More broadly, the case comes amid a long term decline in the use of the death penalty in the United States. Executions and new death sentences have trended downward over the past two decades, driven by changing public opinion, prosecutorial discretion, and legal hurdles to carrying out capital punishment. A decision clarifying intellectual disability standards could shape that trajectory by either removing an important constitutional check or by strengthening protections that have contributed to the broader retreat from capital sentencing.

Legal scholars and state officials will watch the Court for guidance on evidentiary protocols, error margins in IQ testing, and the role of expert clinical judgments. The outcome will determine not only whether Mr. Smith faces execution, but also how courts nationwide will balance medical assessment and constitutional protections in one of the most consequential areas of criminal law. Reuters covered the arguments on December 10.