The Supreme Court says the death penalty is unconstitutionally cruel for juvenile killers. Justices ruled five-to-four that the Constitution forbids executing anyone for a crime committed before the age of 18. The ruling ends a practice used in 19 states and tosses out death sentences of about 70 juvenile murderers. It also blocks states from seeking to execute minors for future crimes. The court had already barred the death penalty for defendants 15 years of age or younger at the time of the crime. In the ruling, Justice Anthony Kennedy writes society sees juveniles "as categorically less culpable than the average criminal." In 2002, justices banned the execution of mentally retarded people.