The Supreme Court abolished capital punishment for juvenile offenders yesterday, ruling 5 to 4 that it is unconstitutional to sentence anyone to death for a crime he or she committed while younger than 18.
In concluding that the death penalty for minors is cruel and unusual punishment, the court cited a "national consensus" against the practice, along with medical and social-science evidence that teenagers are too immature to be held accountable for their crimes to the same extent as adults.
Christopher Simmons, age 17 when he kidnapped and killed a woman, was spared along with 72 others.
The court said its judgment, which overturned a 1989 ruling that had upheld the death penalty for 16- and 17-year-old offenders, was also influenced by a desire to end the United States' international isolation on the issue.
As of yesterday, 20 states, including Virginia, permitted the death penalty for offenders younger than 18. That is five fewer than allowed the practice in 1989.
"From a moral standpoint, it would be misguided to equate the failings of a minor with those of an adult, for a greater possibility exists that a minor's character deficiencies will be reformed," Justice Anthony M. Kennedy wrote in the opinion for the court.
"Our determination," Kennedy added, "finds confirmation in the stark reality that the United States is the only country in the world that continues to give official sanction to the juvenile death penalty."
The ruling was the second time in three years the court had carved out a new categorical exception to the death penalty, having banned capital punishment for the moderately mentally retarded in 2002.
It came after 59 people were executed in 2004, the fewest since the Supreme Court permitted states to resume the death penalty in 1976. That decline is the result in part of lower murder rates and in part of events such as the exoneration of some death row inmates by DNA evidence.
Thus, the ruling showed that society's reconsideration of capital punishment has penetrated the court, with the four liberal justices who joined Kennedy yesterday -- John Paul Stevens, David H. Souter, Ruth Bader Ginsburg and Stephen G. Breyer -- pushing hardest to change capital punishment with the occasional help of either Kennedy or his fellow moderate conservative on the court, Sandra Day O'Connor.
O'Connor, who voted with the four death penalty skeptics and Kennedy in the 2002 case, dissented yesterday, along with the court's conservatives, Chief Justice William H. Rehnquist and Justices Antonin Scalia and Clarence Thomas.
By striking down yesterday the death sentence a Missouri jury had imposed on Christopher Simmons -- who was 17 on Sept. 8, 1993, when he broke into Shirley Crook's house, kidnapped her and threw her, bound and gagged, into a river -- the court also canceled the death sentences of 72 others for crimes they committed while younger than age 18.
One of those inmates, Shermaine A. Johnson, 26, had been awaiting execution in Virginia for a rape and murder he committed in 1994 at age 16. Virginia set a minimum death-penalty eligibility age at 16, but that is now unconstitutional. Maryland bars the death penalty for those younger than 18; there is no death penalty in the District.
By far the largest impact of yesterday's ruling will be felt in Texas, where there are 29 juvenile offenders awaiting execution, and Alabama, where there are 14. No other state has more than five.
There have been 22 executions of juveniles since 1976, 13 of them in Texas.