In a significant decision handed down today by the U.S. Supreme Court, Justice Clarence Thomas, writing for a 5-4 majority that included the Court’s four most liberal justices, held that the Sixth Amendment right to a trial by jury was violated when a judge recommended a mandatory minimum sentence based on a factual finding that had not been reached by the jury.

The case of Alleyne v. United States arose out of an armed robbery committed by Allen Ryan Alleyne and an accomplice. According to federal law, anyone who “uses or carries a firearm” while committing a “crime of violence” is subject to a mandatory minimum sentence of seven years in prison “if the firearm is brandished” and five years if it is not. The jury that convicted Alleyne did not find that he “brandished” a weapon. However, the trial judge in the case still recommended a seven-year sentence.

Pointing to “the historic role of the jury as an intermediary between the State and criminal defendants,” Justice Thomas declared the judge’s actions to be in violation of Alleyne’s constitutional rights. “The essential Sixth Amendment inquiry is whether a fact is an element of the crime,” Thomas wrote. “When a finding of fact alters the legally prescribed punishment so as to aggravate it, the fact necessarily forms a constituent part of a new offense and must be submitted to the jury.”

This ruling is likely to have major ramifications for all criminal suspects facing mandatory minimum sentences.