A death sentence may not be imposed on juvenile offenders. Decided March 1, 2005 (argued October 13, 2004). Opinion of the Court: Anthony Kennedy → go there Dissenting: Scalia, O'Connor. Applied: the Eighth Amendment → go there Applied: the Fourteenth Amendment → go there Topic: Capital punishment. Roper v. Simmons, 543 U.S. 551 (2005), is a landmark decision by the Supreme Court of the United States in which the Court held that it is unconstitutional to impose capital punishment for crimes committed while under the age of 18. The 5–4 decision overruled Stanford v. Kentucky, in which the court had upheld execution of offenders at or above age 16. Roper overturned statutes in 19 states. Wiki link