WASHINGTON ― The Supreme Court on Monday gave a new day in court to five Arizona defendants who were sentenced to spend the rest of their days in prison without the possibility of ever getting out.

What the five cases have in common is that every defendant was sentenced to life without the possibility of parole while they were still under the age of 18 ― a type of sentence the high court has said should be given to minors only in extreme circumstances.

In 2012, the justices had ruled that automatically sentencing children to life without parole is unconstitutional, and earlier this year the Supreme Court supplemented that ruling by making it retroactive to earlier cases.

In light of those decisions, the court on Monday decided the five Arizona cases summarily, which means it simply reversed the sentences without the need for oral arguments or issuing a signed opinion.

But in a concurrence, Justice Sonia Sotomayor wrote separately to explain the standard she and her colleagues were applying, and what it means for the sentencing judges who will now have to carry out the “meaningful task” of resentencing these defendants.

“Children are constitutionally different from adults for purposes of sentencing in light of their lack of maturity and underdeveloped sense of responsibility, their susceptibility to negative influences and outside pressure, and their less well-formed character traits,” she wrote.

In view of these developmental differences, Sotomayor said, the Constitution requires judges to determine “whether the juvenile offender ... is a child whose crimes reflect transient immaturity or is one of those rare children whose crimes reflect irreparable corruption for whom a life without parole sentence may be appropriate.”

Joined by Justice Clarence Thomas, Justice Samuel Alito dissented from the court’s determination and said Arizona courts already sentenced these juveniles ― all of whom were convicted of murder and other aggravated offenses ― by taking into account their youth.

“It is not clear why this Court is insisting on a do-over, or why it expects the results to be any different the second time around,” Alito wrote. He dedicated a separate portion of his dissent to recounting the crimes these youth committed.

The Fair Punishment Project, which tracks legal developments with the death penalty and other severe forms of punishment, published an issue brief earlier this month interpreting how the Supreme Court now views life without parole sentences for youth. Its analysis is closer to Sotomayor’s than Alito’s.