In the case of Mays, Warden v. Hines in 2020, the United States Supreme Court ruled on a habeas corpus petition from an inmate named Byron Black who was convicted for three murders and sentenced to death in Tennessee state court. The issue at hand was whether or not Mr. Black's intellectual disability exempted him from capital punishment under Atkins v. Virginia (2002). The Sixth Circuit had granted relief based on evidence that suggested he might be intellectually disabled but did not consider all aspects of his adaptive functioning as required by Moore v Texas (2017). In a per curiam decision, the Supreme Court vacated this judgment and remanded it back to lower courts for further consideration consistent with its opinion in Bobby v Bies (2009) which held that post-Atkins developments do not excuse failure to make a claim of mental incapacity before Atkins if there were no procedural obstacles preventing such claims.

In the dissenting opinion for Mays, Warden v. Hines, Justice Alito disagreed with the majority's decision to grant relief based on ineffective assistance of counsel during sentencing. He argued that there was no reasonable probability that a different sentence would have been imposed if the jury had heard additional mitigating evidence about Hines' troubled childhood and mental health issues. According to him, this is because the aggravating factors in his case were overwhelming: he committed two murders within 48 hours and showed no remorse or empathy for his victims. Furthermore, he pointed out that even though some jurors might have felt sympathy for Hines due to his difficult background, it does not necessarily mean they would have voted against death penalty given these serious crimes. Therefore, Justice Alito concluded that any deficiencies in representation did not prejudice Hines' defense.