In Roper v. Simmons, decided March 1, 2005, the U.S. Supreme Court held that the Eighth Amendment forbids executing anyone who was under eighteen when they committed their crime. Justice Anthony Kennedy wrote the 5–4 opinion, which overruled a 1989 precedent, removed roughly 70 people from death rows across the country, and set a constitutional floor no state can drop below no matter how severe the offense.
The Crime and the Defendant
Christopher Simmons was seventeen in September 1993 when he planned a burglary and murder in Missouri. He recruited two friends, one fifteen and one sixteen; the sixteen-year-old backed out. Simmons and the younger boy broke into Shirley Crook’s home in the early morning, bound her with duct tape and electrical wire, drove her in her own minivan to a state park, and threw her from a railroad trestle into the Meramec River, where she drowned. Simmons was arrested after bragging about the killing. A jury convicted him of first-degree murder and recommended death, and the trial court imposed that sentence.
His case moved through the Missouri courts for nearly a decade. In 2002, the Supreme Court decided Atkins v. Virginia, which barred executing people with intellectual disabilities on the ground that a national consensus had shifted. Simmons’ attorneys argued the same logic applied to juveniles. The Missouri Supreme Court agreed, set aside his death sentence, and resentenced him to life without parole. Missouri petitioned the U.S. Supreme Court, which took the case.
The Question Before the Court
The question was whether executing a person for a crime committed while under eighteen violates the Eighth Amendment’s ban on cruel and unusual punishment, as applied to the states through the Fourteenth Amendment. A “yes” required overruling Stanford v. Kentucky (1989), which had permitted the execution of sixteen- and seventeen-year-old offenders. A “no” would reinstate Simmons’ death sentence.
The Holding
Justice Kennedy, joined by Justices Stevens, Souter, Ginsburg, and Breyer, held that the Eighth and Fourteenth Amendments forbid the death penalty for offenders who were under eighteen at the time of their crime. The opinion expressly overruled Stanford v. Kentucky, making eighteen a nationwide constitutional bright line for death-penalty eligibility. Around 70 inmates on death rows across the country had their sentences commuted, most to life without parole.
Why the Court Ruled That Way
Evolving Standards of Decency
Kennedy applied the “evolving standards of decency” doctrine, which treats the Eighth Amendment as reflecting society’s maturing moral judgment. Thirty states prohibited the juvenile death penalty at the time of the ruling: twelve had abolished capital punishment altogether, and eighteen kept it but excluded juveniles. Even in states where juvenile executions remained legal, prosecutors rarely sought them and juries rarely returned them. Formal legislative action combined with practical abandonment, the Court said, showed a genuine national consensus.
Three Ways Juveniles Differ From Adults
The Court identified three characteristics that make juvenile offenders categorically less culpable than adults:
- Immaturity and recklessness. Young people lack the maturity and sense of responsibility of adults, which leads to impulsive decisions. Nearly every state already recognizes this by barring those under eighteen from voting, serving on juries, or marrying without parental consent.
- Vulnerability to outside pressure. Juveniles are more susceptible to peer pressure and negative influences, partly because as legal minors they cannot simply leave a bad environment the way an adult can.
- Character still forming. A teenager’s personality is more transitory than an adult’s, so even a terrible crime at seventeen does not necessarily reflect an irredeemable nature.
Because juveniles are less culpable as a category, the Court reasoned, neither retribution nor deterrence justifies executing them. A brief from the American Psychological Association presented MRI research showing that brain regions governing decision-making, impulse control, and long-term thinking continue developing into young adulthood, and argued that predicting future dangerousness in a teenager is too unreliable to meet constitutional standards.
International Opinion
The majority noted that the United States was one of very few countries that still permitted executing juvenile offenders. Kennedy cited the United Nations Convention on the Rights of the Child, which prohibits capital punishment for offenses committed by anyone under eighteen. He treated the international consensus as confirmatory rather than binding, reinforcing the domestic conclusion.
The Dissents
Justice Scalia
Justice Scalia, joined by Chief Justice Rehnquist and Justice Thomas, argued that five justices had substituted their own moral views for those of elected legislatures. He objected to counting states that had abolished the death penalty entirely as part of the “consensus” against juvenile execution, comparing it to “including old-order Amishmen in a consumer-preference poll on the electric car.” He said the idea that American constitutional interpretation should conform to foreign law “ought to be rejected out of hand,” and pointed out that the Senate and the President had declined to ratify the treaties the majority cited. He also faulted the Missouri Supreme Court for effectively overruling Stanford on its own, a power he said belonged only to the U.S. Supreme Court.
Justice O’Connor
Justice O’Connor wrote separately. She agreed Simmons should not be executed, but rejected a categorical rule. In her view, the evidence of national consensus was too thin, and juries could adequately weigh a defendant’s youth as a mitigating factor at sentencing. She wrote that “some 17-year-old murderers are mature enough to deserve the death penalty in an appropriate case.” She parted with Scalia on international law, saying the Court had consistently consulted foreign sources for nearly half a century; she simply found the combined evidence insufficient for a bright-line ban.
How Roper Shaped Later Juvenile Sentencing
Roper did more than end the juvenile death penalty. It set out a framework the Supreme Court has returned to repeatedly, each time extending the idea that young people are constitutionally different from adults for sentencing purposes.
- Graham v. Florida (2010). Sentencing a juvenile to life without parole for a non-homicide crime violates the Eighth Amendment. Young offenders must have “a meaningful opportunity to rejoin society.”
- Miller v. Alabama (2012). Mandatory life without parole for juvenile homicide offenders is unconstitutional. A court can still impose that sentence, but only after considering the defendant’s youth and individual circumstances.
- Montgomery v. Louisiana (2016). The Miller rule applies retroactively, so inmates already serving mandatory juvenile life-without-parole sentences can seek relief. States can satisfy this by offering parole eligibility instead of full resentencing hearings.
- Jones v. Mississippi (2021). By 6–3, the Court held that a sentencing judge need not make a specific finding that a juvenile is “permanently incorrigible” before imposing life without parole. A discretionary system that allows consideration of youth is enough.
The line from Roper through Jones shows a Court that expanded juvenile protections substantially over fifteen years, then eased the procedural requirements in its most recent word. The core principle from Roper is still in place: children are constitutionally different from adults for sentencing, and the law has to account for that difference. What continues to shift is how much process courts must supply when they apply it.