In a trilogy of cases, the Supreme Court applied the Eighth Amendment to the entire category of juvenile offenders, repudiated its “death is different” jurisprudence, and required states to consider youthfulness as a mitigating factor in sentencing. Roper v. Simmons prohibited states from executing offenders for murder they committed when younger than eighteen years of age.1 Roper reasoned that immature judgment, susceptibility to negative influences, and transitory personalities reduced youths’ culpability and barred the most severe sentence.2 Graham v. Florida extended Roper’s diminished responsibility rationale and prohibited states from imposing life without parole (LWOP) sentences on youths convicted of nonhomicide offenses,3 and repudiated the Court’s earlier Eighth Amendment position that “death is different.”4 Miller v. Alabama and Jackson v. Hobbs [Miller/Jackson], combined Roper and Graham’s diminished responsibility rationale with another strand of death penalty jurisprudence to bar mandatory LWOP sentences for youths convicted of murder,5 required judges to make individualized sentencing decisions, and emphasized the importance of youthfulness as a mitigating factor
