Iowa’s Supreme Court ruled 4-3 Friday that a sentence of life without parole for juvenile offenders convicted of first-degree murder amounted to cruel and unusual punishment under the state’s constitution.

Here’s the ruling, in part:

In sum, we conclude that sentencing courts should not be required to make speculative up-front decisions on juvenile offenders’ prospects for rehabilitation because they lack adequate predictive information supporting such a decision. The parole board will be better able to discern whether the offender is irreparably corrupt after time has passed, after opportunities for maturation and rehabilitation have been provided, and after a record of success or failure in the rehabilitative process is available.

The court’s decision remanded the case, State of Iowa vs. Isaiah Richard Sweet, to the district court for re-sentencing.

At issue was the case of Sweet, who was 17 when he killed his grandparents at their home in 2012. A lower-court judge sentenced him in 2014 to life in prison without parole, saying Sweet was “extremely dangerous” and unlikely to be rehabilitated.

Friday’s decision overturned that ruling, but the Supreme Court did add:

Nothing in this opinion, of course, suggests that a juvenile offender is entitled to parole. The State is not required to make such a guarantee, and those who over time show irredeemable corruption will no doubt spend their lives in prison. The determination of irredeemable corruption, however, must be made when the information is available to make that determination and not at a time when the juvenile character is a work in progress.

This article is part of our Next America: Criminal Justice project, which is supported by a grant from the John D. and Catherine T. MacArthur Foundation.