The availability of a mental health expert independent of the prosecution was critical to the case, Dunham argued.
"An independent mental health expert would have been able to explain that McWilliams had brain damage and other serious mental health impairments," Dunham said, "but without an independent mental health expert, the Alabama trial judge who imposed the sentence found no mitigating evidence at all."
"It's not unusual that the prosecution will present a mental health expert or a forensic expert who offers unscientific or even junk science testimony," he added. "We've had dozens of cases where prosecutors have presented junk science testimony about bite marks" or "microscopic hair comparison."
Justice Samuel Alito wrote the dissenting opinion, joined by Justices Clarence Thomas, John Roberts, and Neil Gorsuch. The question at hand, he argued, was whether the defense is entitled to a mental health expert that it can select.
"We granted review in this case to decide a straightforward legal question on which the lower courts are divided: whether our decision in Ake v. Oklahoma, 470 U. S. 68 (1985), clearly established that an indigent defendant whose mental health will be a significant factor at trial is entitled to the assistance of a psychiatric expert who is a member of the defense team instead of a neutral expert who is available to assist both the prosecution and the defense," he wrote.
"The answer to that question is plain: Ake did not clearly establish that a defendant is entitled to an expert who is a member of the defense team," he stated.
Ultimately, the decision will have wide-ranging effects in the justice system, Dunham said, affecting more inmates than McWilliams.
Two inmates in Arkansas, Bruce Ward and Don Davis, recently received stays of execution based on the outcome of the McWilliams case. Their scheduled executions were two of eight that were planned by the state in the span of 10 days in April, and because of Monday's decision they now have "an opportunity to get relief," Dunham said.
Monday's decision is also significant because the Supreme Court found precedent in the case. Thus, it was able to apply the 1985 Ake decision to McWilliams' case, which began shortly after that decision was issued.
Dozens of inmates have been executed, Dunham said, because "the courts have not applied the Constitution to their cases." Now, this precedent can apply to all cases dating back to 1985.
McWilliams' counsel of record Stephen Bright stated that the decision is ultimately "about fairness."
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"The adversarial process cannot function properly if the prosecution can retain mental health experts, but the defense is not even allowed to consult with an expert," he stated.
"James McWilliams could not have a fair trial without a mental health expert to assess his brain damage and other mental impairments and to help his counsel present that information to the sentencing court. He was denied such assistance."
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.