A broad array of individuals and groups ranging from Jimmy Carter to Mikhail Gorbachev and the American Medical Association to the U.S. Conference of Catholic Bishops urged the Supreme Court yesterday to declare that it is unconstitutional to execute people for crimes they committed before turning 18.

The United States is one of five countries that execute juvenile offenders, a practice that shocks European allies and violates "minimum standards of decency shared by virtually every nation in the world," nine eminent former U.S. diplomats told the court in one of 15 briefs filed yesterday. Virginia is one of seven states that execute juvenile offenders.

In 2002 the court, invoking the concept of "evolving standards of decency," abolished capital punishment for mentally retarded offenders. The briefs filed yesterday are part of a campaign by death-penalty opponents to persuade the court to apply similar reasoning in regard to juveniles.

The court is scheduled to hear oral arguments in the fall in the case of Christopher Simmons, now 27, who was sentenced to death for the 1993 drowning of Shirley Crook, 46.

Simmons was 17 when he and a 15-year-old accomplice broke into Crook's mobile home near Fenton, Mo., intending to burglarize it. Fearing that she had recognized them, they bound her with duct tape and electrical wire and kicked her off a bridge into a river.

Missouri's Supreme Court overturned Simmons's death sentence in August, ruling that the execution of juvenile offenders violates the Constitution's ban on cruel and unusual punishment. The state of Missouri appealed that ruling.

The U.S. Supreme Court agreed in January 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. Since 1988, the court has barred execution of those 15 and younger.

Four justices -- Stephen G. Breyer, Ruth Bader Ginsburg, David H. Souter and John Paul Stevens -- have said that imposing the death penalty for offenses by 16- and 17-year-olds is "inconsistent with evolving standards of decency in a civilized society." But thus far, they have not attracted the fifth vote they need to overturn the practice, which is increasingly rare.

Since the Supreme Court allowed executions to resume in 1976, 22 people have been put to death for crimes committed as minors. Thirteen of them were in Texas. Virginia ranked second, with three, and Oklahoma ranked third, with two.

Meanwhile, the federal government, the U.S. military and 31 states, including Maryland, have abolished the death penalty for juveniles. The District of Columbia has banned capital punishment. Forty-three states have not executed a juvenile since 1976.

Virginia's death penalty laws received renewed scrutiny during the sniper prosecutions last year. When Attorney General John D. Ashcroft turned Lee Boyd Malvo, who was 17 during the October 2002 shootings, and fellow sniper John Allen Muhammad over to Virginia authorities, he said they deserved execution if they were convicted -- and Virginia offered the opportunity to execute Malvo.

Malvo was convicted but spared a death sentence. Muhammad, who was sentenced to death, is set to be tried in other shootings, and Virginia prosecutors have said they will wait until the court decides the Missouri case before they decide whether to proceed with a second trial for Malvo.

Prince William County Commonwealth's Attorney Paul B. Ebert, who has sent more killers to death row than any Virginia prosecutor, said age should be taken into account but should not be a "disqualifying factor" for capital punishment.

"I don't think we can . . . say that someone who is 17 years and 6 months old should be treated differently than someone who is 18," Ebert said. "A lot of these kids are a lot more mature than adults. . . . We have outstanding young athletes. We have outstanding young scholars, and unfortunately we have outstanding young murderers."

Lawyers for six states -- Virginia plus Alabama, Delaware, Oklahoma, Texas and Utah -- are supporting Missouri's contention that the death penalty is appropriate for some teenage killers.

A "bright-line rule categorically exempting 16- and 17-year-olds from the death penalty -- no matter how elaborate the plot, how sinister the killing, or how sophisticated the coverup -- would be arbitrary at best and downright perverse at worst," they said in a friend-of-the-court brief filed in April.

In the briefs filed yesterday, 48 nations, 18 Nobel Peace Prize winners, 28 U.S. religious groups and a host of medical, legal and child advocacy groups argued against executing juvenile offenders.

"Adolescents as a group, even at the age of 16 or 17, are more impulsive than adults. They underestimate risks and overvalue short-term benefits. They are more susceptible to stress, more emotionally volatile, and less capable of controlling their emotions than adults," said a brief submitted by the American Medical Association and other medical groups.

The retired diplomats, including former ambassadors Thomas R. Pickering, Stuart E. Eizenstat and Felix G. Rohatyn, wrote that in the last four years only five countries -- China, Congo, Iran, Pakistan and the United States -- have executed juvenile offenders.

"While I was ambassador, I don't think there was any issue, including even when we were bombing Iraq and Bosnia, that elicited as much anger and demonstrations as executions in the United States," Rohatyn, who served as ambassador to France from 1997 to 2000, said in an interview.

"From the elites down to the common man, this is viewed in Europe as a very basic failing of our society," he said.

Mark Chopko, general counsel to the U.S. Conference of Catholic Bishops and author of the brief by religious groups, said all major religions teach that "the young don't have the same moral culpability" as adults.

"There is a great consensus among religious organizations that executing juveniles should offend the sense of decency in any society," he said.

Staff writer Maria Glod contributed to this report.