In a 2012 U.S. Supreme Court case, Miller v. Alabama, the Justices decided that a mandatory life-without-parole sentence for a juvenile convicted of homicide is cruel and unusual punishment. (567 U. S. ___ (2012).) In an early 2016 decision, Montgomery v. Louisiana, the Court has clarified Miller and determined that the case applies retroactively. (577 U. S. ____ (2016).)
The Court explained that a sentence of life without parole (LWOP) is too much for all but “the rare juvenile offender whose crime reflects irreparable corruption.” In other words, a court has to determine that a juvenile who committed a crime like murder is essentially beyond hope before locking up the juvenile and throwing away the key.
The Court also said that the rule on LWOP for juveniles applies to cases decided before the 2012 Miller decision. Though the procedural rules are complicated in this area and states can throw up roadblocks, the Court has basically allowed affected prisoners whose convictions became final by mid-2012 a chance at release. These prisoners would have, at a minimum, the opportunity to show that, at the time of their sentencing, they weren’t incapable of rehabilitation.