In the case of Daniel v. Louisiana, 1974, the U.S. Supreme Court was asked to consider whether a state law that allowed non-unanimous jury verdicts in criminal cases violated the Sixth Amendment's guarantee of a fair trial by an impartial jury. The petitioner, Gary Duncan, had been convicted by a vote of nine to three and argued that this did not meet the constitutional standard for conviction beyond reasonable doubt. However, his appeal was dismissed on procedural grounds without addressing this substantive issue. The court held that because Duncan had failed to raise his objection at trial or on direct review - instead waiting until he filed for post-conviction relief - he could not now challenge his conviction based on this argument. This decision reinforced previous rulings emphasizing defendants' responsibility to assert their rights promptly and properly during legal proceedings.

In the dissenting opinion for Daniel v. Louisiana, it was argued that the majority's decision to uphold a state law allowing non-unanimous jury verdicts in criminal cases violated the Sixth Amendment right to a fair trial by an impartial jury. The dissenting justices believed that this practice undermined the fundamental principle of requiring consensus among jurors before convicting someone of a crime. They contended that permitting convictions based on less than unanimous agreement could lead to unjust outcomes and potentially compromise defendants' rights. Furthermore, they expressed concern about potential racial bias in such decisions given historical context and patterns of discrimination within juries. Therefore, they disagreed with upholding Louisiana's non-unanimous jury rule as constitutional.