Earlier this year, only two states still permitted nonunanimous jury convictions—Louisiana and Oregon. The U.S. Supreme Court's Ramos v. Louisiana decision in April 2020 held that unanimity is required under the Sixth Amendment. That decision applied only to cases on direct appeal; it did not apply to cases under collateral review (i.e., habeas corpus petitions filed after direct appeals were exhausted). To address the collateral-review question, the court quickly agreed to consider the issue this term in Edwards v. Vannoy.

Supreme Court decisions are not usually applied retroactively to cases on collateral review. According to the court's 1989 decision of Teague v. Lane, only a "watershed" rule of criminal procedure should apply retroactively to collateral challenges. In the three decades since Teague was decided, not once has the court held that one of its decisions established a watershed rule. The only procedural right the court has decided to apply retroactively, which was decided pre-Teague, was the right to an attorney, as set forth in Gideon v. Wainwright (1963). Most notably, not even Batson v. Kentucky (1986) (prohibiting peremptory challenges to jurors based on race) was applied retroactively.