Some states, however, thought this decision gave them broader discretion than was warranted to determine disability, he said. States like Texas and Florida used non-clinical standards, which led to later cases like Moore and Hall v. Florida where the Court found those standards unconstitutional.
"I think what the Court intended in Atkins, that discretion was not set up so that states could nullify Atkins by creating inappropriate hurdles for proving intellectual disability," Dunham noted.
The majority opinion in Moore, authored by Justice Ruth Bader Ginsburg who was joined by Justices Stephen Breyer, Anthony Kennedy, Sonia Sotomayor, and Elena Kagan, "said the state's discretion is not unfettered," Dunham said.
"All the members of the Court agreed that the intellectual disability determination needs to be informed by the diagnostic framework."
Texas' Briseno standard for evaluating intellectual disability is "an invention of the CCA [Criminal Court of Appeals] untied to any acknowledged source," the Court stated, saying the standards were an "outlier" as other states had not adopted them and Texas did not even use them for cases other than the death penalty.
"Not aligned with the medical community's information, and drawing no strength from our precedent, the Briseno factors 'creat[e] an unacceptable risk that persons with intellectual disability will be executed'," the opinion stated.
"Mild levels of intellectual disability, although they may fall outside Texas citizens' consensus, nevertheless remain intellectual disabilities," they insisted.
The dissent, written by Chief Justice John Roberts and joined by Justices Clarence Thomas and Samuel Alito, admitted that the Briseno factors "are an unacceptable method of enforcing the guarantee of Atkins."
However, Roberts added that he did not think the appeals court "erred as to Moore's intellectual functioning."
Furthermore, the Court majority set about determining what was the "medical consensus about intellectual disability" when that judgment should be left to "clinicians," Roberts insisted.
Ultimately, the Court sent a strong message not only to Texas but to other states who craft their testing for intellectual disability outside of the clinical consensus, Dunham said.
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"This case, Moore and Hall read together, sends a clear message. That is, if you follow the clinical definitions of intellectual disability, you aren't going to have these kinds of problems. When you start substituting lay stereotypes and myths for the clinical criteria, you're risking having your court judgments overturned."
"This decision sheds light on one of the many broken aspects of the death penalty. Today's Supreme Court ruling is another step towards justice for all life," Clifton stated.
Matt Hadro was the political editor at Catholic News Agency through October 2021. He previously worked as CNA senior D.C. correspondent and as a press secretary for U.S. Congressman Chris Smith.