The Michigan Supreme Court says judges, not juries, have the sole power to decide whether someone under 18 gets life in prison without parole.
The 4-2 opinion, released Wednesday, centers on murder cases from St. Clair County and Genesee County.
Many new sentencing hearings for so-called juvenile lifers have been on hold while a decision was in the works.
The Supreme Court says there are no constitutional violations in allowing a judge to order a no-parole sentence for a teen under 18.
Chief Justice Stephen Markman says a trial judge doesn't need to find any particular fact before choosing the highest punishment.
Justices Bridget McCormack and Richard Bernstein disagreed.
They also said a no-parole sentence for minors should be reviewed by appellate courts under a strict standard.