Determining Intellectual Disability in Death Penalty Cases: A State-by-State Analysis

In Moore v. Texas (2017), the U.S. Supreme Court ruled that Texas death penalty definitions of intellectual disability were inadequate because they strayed too far from clinical definitions. This study examines how each state defines intellectual disability with regard to death penalty eligibility. It reveals a wide variation in the standards used by states, with no clear consensus on definitions of intellectual disability or who should measure it. Variations pertain to age at onset, proof of intellectual disability status at the time of the crime, burden of proof required to make the intellectual disability determination, and who makes the final decision. Implications and suggestions for the future are discussed.