What reasons did the Supreme Court give for changing lifetime sentences to youths and How did states react to the changes in laws from the Supreme Court decisions?

Justice Anthony M. Kennedy proclaimed that juveniles that are convicted even of the most heinous crimes should not be treated in the same way as adults. The court back in 2005 eliminated the capital punishment for juveniles and subsequently said that they could not be imprisoned for life for crimes other than murder and their hope living outside prison must be restored. Justice Kennedy also mentioned that, "children's diminished culpability and heightened capacity for change" cast doubt on mandatory sentences, and that this "harshest possible penalty will be uncommon."

The aforementioned change spread quickly across the nation, with individual state, where most juvenile justice issues are settled, which are using the same course of actions that are especially designed to rehabilitate juveniles, so much as the most grave cases. However, new change happened all over the United States when it comes to the treatment and arbitration of juveniles related to delinquency and criminal matters over the past twenty years.