The Supreme Court ruled Monday that people sentenced to life in prison as juveniles should be able to petition for a review and possibly earn parole.

In a 6-3 ruling, the court said a 2012 decision prohibiting anyone under the age of 18 from being sentenced to life without parole should be retroactive.

{mosads}The court revisited the 2012 decision in a challenge from Henry Montgomery, who was sentenced to life in prison without parole for killing a sheriff’s deputy in Baton Rouge, La., in 1963 at the age of 17.

In delivering the opinion of the court, Justice Anthony Kennedy said that the court’s decision in Miller v. Alabama made juvenile offenders eligible for parole.

“This would neither impose an onerous burden on the states nor disturb the finality of state convictions,” he said. “And it would afford someone like Montgomery, who submits that he has evolved from a troubled, misguided youth to a model member of the prison community, the opportunity to demonstrate the truth of Miller’s central intuition—that children who commit even heinous crimes are capable of change.”

Kennedy said the court’s ruling does not automatically mean people serving life terms will get new sentences, only the right to a review.

“The opportunity for release will be afforded to those who demonstrate the truth of Miller’s central intuition—that children who commit even heinous crimes are capable of change,” he added.

In his dissenting opinion, Justice Antonin Scalia said the Supreme Court did not have jurisdiction to decide the case.

“Once a conviction has become final, whether new rules or old ones will be applied to revisit the conviction is a matter entirely within the State’s control; the Constitution has nothing to say about that choice,” he said.

His dissent was joined by Justices Clarence Thomas and Samuel Alito.

Monday’s decision reverses the Louisiana Supreme Court court’s ruling and sends the case back to the lower courts.