In an historic ruling, the United States Supreme Court has ruled that laws requiring youths convicted of murder to be sentenced to die in prison violate the Eighth Amendment’s ban on cruel and unusual punishment.

Writing for the majority in the decision concerning juvenile offenders, Justice Elena Kagan said the Constitution forbids “requiring that all children convicted of homicide receive lifetime incarceration without possibility of parole, regardless of their age and age-related characteristics and the nature of their crimes.”

The New York Times reports:

“In barring the punishment for killings committed before age 18, Justice Kagan drew on two lines of precedent, both rooted in the court’s death penalty jurisprudence.

The first concerned harsh penalties imposed on juvenile offenders. In 2005, in Roper v. Simmons, the court eliminated the juvenile death penalty. In 2010, in Graham v. Florida, the court ruled that sentencing juvenile offenders to life without the possibility of parole was also unconstitutional, but only for crimes that did not involve killings. That decision affected about 130 prisoners convicted of committing, before they turned 18, crimes like rape, armed robbery and kidnapping.

The new decision did not draw a categorical line. Instead, the majority looked to a second line of cases, these barring mandatory death sentences and insisting instead that judges and juries, in Justice Kagan’s words, “consider the characteristics of a defendant and the details of his offense before sentencing.”

The problem with mandatory sentences, Justice Kagan wrote, is that “every juvenile will receive the same sentence as every other — the 17-year-old and the 14-year-old, the shooter and the accomplice, the child from a stable household and the child from a chaotic and abusive one.”

“Mandatory life without parole for a juvenile precludes consideration of his chronological age and its hallmark features — among them, immaturity, impetuosity, and failure to appreciate risks and consequences,” Justice Kagan added. “It prevents taking into account the family and home environment that surrounds him — and from which he cannot usually extricate himself — no matter how brutal or dysfunctional.”

According to the National Conference of State Legislatures, about 2,500 inmates are serving life sentences for crimes committed when they were juveniles, including more than 2,000 — 80 percent — through the kind of mandatory sentencing systems barred on Monday by the court.