In the 1952 case United States ex rel. Smith v. Baldi, Superintendent, Philadelphia County Prison, the U.S. Supreme Court ruled in favor of prison superintendent Baldi and against prisoner Smith who was on death row for murder charges and had petitioned for a writ of habeas corpus claiming that he did not receive adequate psychiatric assistance during his trial which violated his constitutional rights to due process under the Fourteenth Amendment. The court found no evidence that Smith's legal representation or trial were unfair as there was no obligation at the time to provide psychiatric assistance unless it could be proven that defendant was mentally unfit to stand trial or assist in their own defense; something which wasn't demonstrated by Smith's counsel during his original proceedings nor subsequent appeals.

In the dissenting opinion for United States ex rel. Smith v. Baldi, Justice Frankfurter argued that the court had failed to adequately consider whether Smith's constitutional rights were violated due to his mental illness at trial and sentencing. He contended that a defendant’s sanity is fundamental in ensuring a fair trial as it affects their ability to understand proceedings and assist in their defense effectively. The majority decision, he believed, did not sufficiently address this issue or provide adequate safeguards against potential abuses of mentally ill defendants' rights within the criminal justice system.