In 1963, P killed Charles Hurt, a deputy sheriff. P was 17 years old at the time of the crime. He was convicted of murder and sentenced to death, but the Louisiana Supreme Court reversed his conviction after finding that public prejudice had prevented a fair trial. P was retried. The jury returned a verdict of “guilty without capital punishment.” That verdict required the trial court to impose a sentence of life without parole. The sentence was automatic upon the jury’s verdict. P had no opportunity to present mitigation evidence to justify a less severe sentence. P, now 69 years old, has spent almost his entire life in prison. Almost 50 years after P's conviction, Miller v. Alabama held that mandatory life without parole for juvenile homicide offenders violates the Eighth Amendment’s prohibition on “‘cruel and unusual punishments.’” Miller required that sentencing courts consider a child’s “diminished culpability and heightened capacity for change” before condemning him or her to die in prison. The Court explained that a lifetime in prison is a disproportionate sentence for all but the rarest of children, those whose crimes reflect “‘irreparable corruption.’” P sought collateral review of his mandatory life-without-parole sentence. P argued that Miller rendered his mandatory life-without-parole sentence illegal. The trial court denied P’s motion on the ground that Miller is not retroactive on collateral review. P filed an application for a supervisory writ. The Louisiana Supreme Court denied the application. It held that Miller does not have a retroactive effect in cases on state collateral review. P appealed. The petition presented the question of “whether Miller adopts a new substantive rule that applies retroactively on collateral review to people condemned as juveniles to die in prison.” Amicus contends it is for state courts to define applicable principles of retroactivity. Under this view, the Louisiana Supreme Court’s decision does not implicate a federal right; it only determines the scope of relief available in a particular type of state proceeding-a question of state law beyond this Court’s power to review.