Christopher Simmons was tried, convicted, and sentenced to death for first degree murder for a crime that he committed at age 17. He appealed as of right to the Missouri Supreme Court, which exercises exclusive jurisdiction in death penalty case. In 1997, the Missouri Supreme Court affirmed the conviction and the sentence. State v. Simmons, 944 S.W.2d 165, 169 (Mo. 1997). On his initial appeal, Simmons could not argue that his youth prohibited his execution because the United States Supreme Court held in 1989 that there was no national consensus against the execution of young adults who were sixteen or seventeen years old at the time of their crimes, and that, as a result, executing juveniles was not cruel and unusual punishment under the Eighth Amendment. See Simmons v. Roper, 112 S.W.3d 397, 399 (Mo. 2003) (en banc) (discussing Stanford v. Kentucky, 492 U.S. 361 (1989)). The Missouri Supreme Court thus affirmed the Circuit Court of Jefferson County, Missouri on both the conviction and death sentence. See id.
In 2002, the United States Supreme Court reversed Penry v. Lynaugh, 492 U.S. 302 (1989), which held that a national consensus did not exist against execution of the mentally retarded. Atkins v. Virginia, 536 U.S. 304 (2002). In Atkins, the Supreme Court concluded that such a consensus had developed in the thirteen years since Penry and that executing the mentally retarded violates the Eighth Amendment. Id. at 321. Hoping that the Supreme Court's ruling in Atkins might signal a parallel shift in the Court's view toward the execution of juvenile offenders, Simmons appeared before the Missouri Supreme Court again in 2003 on a writ of habeas corpus, arguing that a national consensus opposing the execution of sixteen- and seventeen-year-old offenders had emerged since Stanford v. Kentucky. Simmons, 112 S.W.3d at 399. The Missouri Supreme Court agreed, reasoning that "the Supreme Court would today hold such executions are prohibited by the Eighth and Fourteenth Amendments." Id. at 400.
The United States Supreme Court agreed to hear Simmons' case in order to address two specific issues. First, the Court will consider whether a lower court may contradict a previous ruling by the Supreme Court. Specifically, the Court will decide whether it was permissible for the Missouri Supreme Court to conclude that the execution of juvenile offenders is cruel and unusual punishment and violates the Eighth Amendment, in direct contradiction to the Supreme Court's ruling in Stanford v. Kentucky. Second, the Supreme Court will decide for itself whether a national consensus now opposes the execution of offenders younger than eighteen years and, therefore, whether the practice now violates the Eighth Amendment's prohibition against cruel and unusual punishment.