The US Supreme Court [official website] ruled [opinion, PDF] Monday in Montgomery v. Louisiana [SCOTUSblog backgrounder] that a landmark decision banning mandatory sentences of life without parole for juveniles should apply retroactively. The Supreme Court reached that decision [JURIST report] in Miller v. Alabama and Jackson v. Hobbs [SCOTUSblog backgrounders] in 2012, but until now the outcome was being applied retroactively only by certain states. The case involves Henry Montgomery, convicted in 1963 of murdering a deputy sheriff at the age of 17. He was sentenced to life in prison without the possibility of parole. Now, at the age of 70, he is asking for a new sentencing hearing in hopes that the ruling in 2012 will apply to his 1963 life sentence. In a 6-3 opinion authored by Justice Anthony Kennedy, the court concluded Monday:

Henry Montgomery has spent each day of the past 46 years knowing he was condemned to die in prison. Perhaps it can be established that, due to exceptional circumstances, this fate was a just and proportionate punishment for the crime he committed as a 17-year-old boy. In light of what this Court has said in Roper, Graham, and Miller about how children are constitutionally different from adults in their level of culpability, however, prisoners like Montgomery must be given the opportunity to show their crime did not reflect irreparable corruption; and, if it did not, their hope for some years of life outside prison walls must be restored.

Justice Antonin Scalia filed a dissenting opinion, joined by Justices Clarence Thomas and Samuel Alito. Thomas also filed a separate dissent.

The Supreme Court heard arguments in the case in October after granting certiorari [JURIST reports] in May. Monday’s decision could affect more than 2,000 people currently serving life terms for homicides committed as juveniles.