Roper v. Simmons

Brief Filed: 7/04
Court: U.S. Supreme Court
Year of Decision: 2005

Read the full-text amicus brief (PDF, 222KB)


Whether the imposition of the death penalty on an individual who was 17 years old when he committed a murder constitutes “cruel and unusual” punishment, and is thus barred by the Eighth and Fourteenth Amendments

Index Topic

Death Penalty (Juveniles)


The U.S. Supreme Court granted review in this case to rule on the constitutionality of the death penalty for juvenile defendants (those under the age of 18 at the time of their crime). This case involves Christopher Simmons, who was 17 when he was arrested for the murder of Shirley Crook. He was convicted of first-degree murder and sentenced to death. In 2003, nine years after his conviction, the Missouri Supreme Court reviewed Simmons’ case. The court invalidated the death sentence in this case noting that it believed that the views of the public and national learned organizations reflect a consensus that would not support such executions. The court determined that juvenile executions violated the Eighth Amendment’s provision against cruel and unusual punishment under the “evolving standards of decency” test. The state of Missouri appealed that ruling. The U.S. Supreme Court agreed to hear the case, which could lead to a reversal of a 1989 decision in which the court upheld the death penalty for crimes committed by 16- and 17-year-olds (Stanford v. Kentucky, 492 U.S. 361). Since 1988, the court has barred execution of those 15 and younger (Thompson v. Oklahoma, 487 U.S. 815).

APA's Position

APA submitted an amicus curiae brief together with the Missouri Psychological Association presenting scientific evidence to assist the court in resolving critical empirical questions relevant to the legal standards governing the death penalty including whether the recognized purposes of the death penalty — deterrence and retribution — apply to 16- and 17-year-olds as a group. The brief presented behavioral research on the developmental characteristics of late adolescents, featuring in particular recent studies from the MacArthur Foundation’s Research Network on Adolescent Development and Juvenile Justice, a collection of experts in psychology, sociology, public policy, law and legal practice. The brief also provides the court with research and expert opinion about the characteristics of adolescents such as less mature decision-making, impulsivity, risk-taking, peer orientation, temporal perspective (the extent to which long term and short term consequences are taken into account) and vulnerability to coercion and false confession. In addition, included was recent relevant MRI research on brain function suggesting that the brain continues to develop through young adulthood in areas that may bear on adolescent decision-making. APA’s brief asserts that a categorical exclusion of 16- and 17-year-olds from the death penalty is warranted based on the research and the fact that assessment of character and likelihood of dangerousness as an adult in the death penalty context cannot be sufficiently reliable to satisfy constitutional standards.


In a 5-4 opinion, delivered by Justice Anthony Kennedy in March 2005, the U.S. Supreme Court ruled that standards of decency have evolved so that executing juvenile offenders who committed while younger than 18 is “cruel and unusual punishment” prohibited by the Eighth Amendment. The majority opinion used several of APA’s arguments in reaching its conclusion. In his dissent supporting the death penalty for juveniles, Justice Scalia asserted that research provided by APA in a 1989 case involving parental consent laws was inconsistent with APA’s position in Simmons. An APA briefing was released in March addressing Justice Scalia’s comments.