Despite being the first state to abolish the capital punishment of defendants with intellectual disability (ID), Georgia is currently the only state to uphold what is considered to be the most stringent standard of proof of ID in the United States: beyond a reasonable doubt. Other states have implemented less stringent standards of proof (i.e., a preponderance of the evidence and clear and convincing evidence). Although the U.S. Supreme Court ruled the execution of persons with ID unconstitutional in the 2002 Atkins decision, states are at this juncture considered to have a great deal of discretion in defining what constitutes ID. In addition to raising concerns about the Eighth Amendment’s protection against cruel and unusual punishment, variation between state-determined definitions of ID raises important questions of equal protection of the law. On January 27, 2015, Mr. Warren Lee Hill was executed by method of lethal injection in the state of Georgia after the U.S. Supreme Court denied Mr. Hill’s claim to have met the state’s legal definition of ID beyond a reasonable doubt. This article provides a historical and legislative background for the case of Warren Lee Hill, while examining the definitions of ID (including adaptive functioning) in the legal and clinical arenas. Last, this article will take a critical stance with regard to the current diagnostic criteria being used in the state of Georgia.