Justice Roberts protested, a bit misleadingly, that the majority had deprived state legislators of the power to require LWOP for juveniles "who commit the worst types of murder." In fact, states may continue to prescribe it for the worst juvenile offenders. What's changed is the process by which LWOP will be applied -- after an individualized assessment of the offender and the crime.
Justice Alito objected strongly to this individualized approach to sentencing. The "category of murderers" under 18 consists mostly of older teenagers who engage in "brutal thrill-killing," Alito declared in dissent. The offenders in the cases before the Court in Miller were "very young"; they were "anamolies," for whom it was "hard not to feel sympathy," he acknowledged. But if some members of the juvenile murderer category are atypical and inappropriate candidates for LWOP, that, Alito suggested, is their misfortune. In his view, 8th Amendment strictures against cruel and unusual punishment do not bar states from imposing excessively harsh sentences on a few juveniles who may not deserve them in order to facilitate their imposition on many teenagers who do.
"No one should be confused by the particulars of the two cases before us," Alito admonished, in a remarkable rejection of individualized justice when it arguably matters most, in the imposition of criminal sentences. Should Alito ever be arrested, I imagine he'll expect and demand to be treated as an individual -- not as a Catholic, or an Italian-American of a certain age, or a member of a conservative Supreme Court bloc, who might be sentenced for the sins of Justice Scalia (whatever they may be). I suspect he'll want to be treated as Samuel Alito, a particular person alleged to have committed a particular crime. Should he ever be arrested, Justice Alito will probably want police, prosecutors, jurors and judges to pay close attention to his particulars, which I doubt he'll condemn as "confusing."
Particularized, individualized justice is precisely what mandatory sentences deny. The Court has declined to strike them down under the 8th Amendment in cases involving adults, although they often dictate excessively, disproportionately harsh sentences, and their role in filling our prisons with non-violent drug offenders is a decades old scandal. Long promoted as a means of eliminated discretion in sentencing, mandatory minimums merely transfer discretion from judges to prosecutors. They ensure that prosecutors decide how defendants will be sentenced when they choose the crimes with which defendants will be charged. In juvenile cases, prosecutors may sometimes choose lengthy, mandatory sentences when they choose to transfer juveniles to adult court.
Now, under Miller, prosecutors may still transfer juvenile homicide suspects, who may still face LWOP for "brutal thrill-killings." But their sentences will no longer be determined by generally unaccountable prosecutors or by the crimes of other juveniles in their "category." This is not an obscure principle, difficult to comprehend. Juvenile offenders are individuals too, not interchangeable members of a class.