John Roberts, Clarence Thomas, Antonin Scalia, and Joseph Alito all agree that locking children away in prisons without a scintilla of hope of ever seeing freedom again is a grand thing.
Miller v. Alabama, states that mandatory life without parole sentences for juveniles is cruel and unusual punishment. Specifically, a 14 year-old was an accomplice to a robbery that resulted in murder and was convicted, the law required life without parole. Should there be an allowance that sometime, decades in the future, he might mature into decent human beings?
Thomas, as usual, stayed with his simplistic belief that the moral conscious of the nation was frozen in carbonite in the year 1787. Anything permitted 200 years ago should be allowed today. If children were punished with the whip in 1790 it should be done today too.
Roberts fixates on the word unusual and concludes that any punishment that is common for 40 year-old career criminals cannot possible be cruel when imposed upon a 14 year-old.
Alito enters a fantasy world. He fabricates some fictitious "17½-year-old" fiend as justification for mandatory sentences of life without parole for a real 14 year-old kid. Alito felt so strongly he read his opinion in open court. Scalia, somehow, managed to keep his trap shut.