In Alleyne v. United States, the court reverses their decision in the 2002 case Harris v. United States, and holds that judges cannot recommend or impose mandatory minimum sentences based on facts that had not been established by the jury in the case at hand. To do so, they ruled, violates the Sixth Amendment right to a jury trial.

Clarence Thomas wrote the opinion for the court, and was joined by Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayhor, and Elena Kagan on four parts. Ginsburg, Sotomayor, and Kagan joined Thomas on two other parts of the ruling, to which Breyer, who wrote his own concurrence, did not agree. John Roberts, joined by Antonin Scalia and Anthony Kennedy, wrote a dissent, as did Samuel Alito.