The case of Lee v. Missouri in 1978 revolved around the issue of whether a state could require a defendant to prove his innocence by clear and convincing evidence when raising an insanity defense, or if this violated due process rights under the Fourteenth Amendment. The Supreme Court ruled that it was not unconstitutional for states to place such burden on defendants. This decision came after Charles Lee, who had been convicted of first-degree murder in Missouri, appealed his conviction arguing that he should have only needed to raise reasonable doubt about his sanity at the time of the crime rather than having to provide clear and convincing proof. However, the court disagreed with him stating that while some jurisdictions might choose different standards for proving insanity defenses, it did not violate due process rights for states like Missouri to require more stringent proof.

In the dissenting opinion for Lee v. Missouri, Justice William Rehnquist argued that the majority's decision to overturn a murder conviction based on an alleged violation of the defendant's Sixth Amendment right to counsel was misguided. He contended that there was no constitutional error in admitting into evidence statements made by the defendant during police interrogation before he had been indicted or arraigned, as long as those statements were voluntary and not coerced. Furthermore, he pointed out that at this stage of proceedings, it is common practice for law enforcement officers to question suspects without their attorneys present. The justice also expressed concern about potential negative implications of this ruling on future criminal investigations and prosecutions.