The U.S. Supreme Court case Allen Ryan Alleyne v. United States in 2012 revolved around the issue of mandatory minimum sentencing and the role of juries versus judges in determining facts that increase criminal penalties. The petitioner, Alleyne, was convicted for using a firearm during a robbery but disputed his mandatory minimum sentence because it was based on judicial fact-finding rather than jury determination. He argued this violated his Sixth Amendment right to trial by jury as established by Apprendi v New Jersey (2000) which ruled any fact increasing penalty beyond statutory maximum must be submitted to a jury and proved beyond reasonable doubt. In a 5-4 decision, the court sided with Alleyne stating that any fact leading to an increased mandatory minimum sentence is an "element" of the crime and should therefore be determined by a jury not judge alone.

In the dissenting opinion for the case of Allen Ryan Alleyne v. United States, Justice Samuel Alito argued that mandatory minimum sentences should be determined by judges, not juries. He contended that this approach was consistent with historical practice and did not violate a defendant's right to a jury trial under the Sixth Amendment. Alito also disagreed with the majority's application of Apprendi v. New Jersey (2000), which held that any fact increasing a sentence beyond its statutory maximum must be found by a jury beyond reasonable doubt; he believed it didn't apply to mandatory minimums as they don't increase punishment above what law prescribes but rather limit judicial discretion in sentencing within prescribed range. Furthermore, he expressed concern about practical implications of requiring juries to determine specific facts related to sentencing, including potential complications in plea bargaining process and increased burden on court system.