In the case of Massey v. Moore, 1954, the U.S Supreme Court ruled in favor of a prisoner who claimed that he was mentally ill at the time of his trial and thus unable to adequately participate in his own defense. The petitioner, Massey, had been convicted for murder by an Ohio court and sentenced to death. He appealed on grounds that he was insane during both the commission of crime and trial proceedings which violated his constitutional rights under due process clause as per Fourteenth Amendment. The Supreme Court agreed with him stating that if a person is not competent enough to consult with their lawyer or understand legal proceedings then they cannot be tried fairly according to law standards set forth by Constitution's Due Process Clause.

In the dissenting opinion for Massey v. Moore, it was argued that the majority's decision to grant a new trial based on an alleged denial of due process was unfounded. The dissenters believed that there were no constitutional violations in how Massey's original trial had been conducted and saw no reason why his conviction should be overturned. They pointed out that while he may not have received perfect representation from his court-appointed attorney, this did not necessarily mean he had been denied a fair trial as required by law. Furthermore, they disagreed with the majority's assertion that Massey’s mental illness at the time of his confession made it involuntary and thus inadmissible evidence; instead arguing such determination is best left to jury discretion rather than judicial speculation.