The 5-4 decision tossed out the death sentence of a Missouri man who was 17 years old when he murdered a St. Louis area woman in 1993. It also overturned laws in 19 states and invalidated the death sentences of some 70 death row inmates who were under 18 at the time of their crimes.

Writing for the majority, Justice Anthony Kennedy cited "society's evolving standard of decency" and a "national consensus against the death penalty for juveniles" in upholding the Missouri Supreme Court judgment setting aside the death penalty imposed on Christopher Simmons.

Simmons planned and committed a murder when he was 17 and a junior in high school. About nine months later, after he had turned 18, he was tried and sentenced to death.

"Our determination that the death penalty is disproportionate punishment for offenders under 18 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," Kennedy wrote.

Supporting Kennedy were justices John Paul Stevens, David Souter, Ruth Bader Ginsburg and Stephen Breyer.

In a dissenting opinion, Justice Antonin Scalia complained, "Words have no meaning if the views of less than 50 percent of death penalty states can constitute a national consensus."

Chief Justice William Rehnquist and justices Sandra Day O'Connor and Clarence Thomas joined Scalia in the dissent.

Former President Jimmy Carter hailed the ruling as acknowledging the "profound inconsistency in prohibiting those under 18 years of age from voting, serving in the military, or buying cigarettes, while allowing them to be sentenced to the ultimate punishment."

"I thank God that the Supreme Court … has at long last ruled against the execution of persons under the age of 18," said the Rev. R. Randy Day, the top mission executive of the United Methodist Church.

The Rev. Sala W.J. Gonzales Nolan, minister for criminal justice and human rights for the United Church of Christ, said the Supreme Court's action is "further evidence that the United States is coming to a new understanding about the immorality of state-sanctioned executions." The United States remains one of the last industrialized countries in the world to impose the death penalty.

"It is one thing to oppose the death penalty because it is unfair," Nolan said. "It is another to oppose it simply because it is wrong."

Tonya McClary, national criminal justice representative for the American Friends Service Committee, said the decision confirms that "Kids are different from adults and by their very nature cannot qualify as the 'worst of the worst' standard used by some to justify a sentence of death."

Many churches oppose the death penalty on moral grounds, including The Evangelical Lutheran Church of America, World Council of Churches, United Methodist Church, Presbyterian Church and Episcopal Church. Pope John Paul II also supports an international campaign against the death penalty.

But not all religious bodies agree.

A resolution adopted by the Southern Baptist Convention in 2000 stated that "God forbids personal revenge and has established capital punishment as a just and appropriate means by which the civil magistrate may punish those guilty of capital crimes."

"For all those who believe juveniles are never culpable enough to deserve capital punishment, consider this: Not everyone in hell is over the age of 18," wrote Mark Creech, executive director of the Christian Action League of North Carolina. "God holds individuals responsible according to their abilities at whatever age to discern right and wrong. In our system of justice, juries are best able to discern all the mitigating factors and determine how culpable a minor is--not high-and-mighty black robed dictators."

Karen England of Capitol Resources Institute, a pro-family group in California, found it "perplexing that the laws in our country, on the one hand, recognize the immaturity of young people to commit crimes while, on the other hand, declare that 12-year-old children in California are allegedly 'mature' enough to make decisions regarding obtaining an abortion or seeking other 'confidential medical services.'"

"If children aren't mature enough to be forced to experience negative consequences of committing a crime, then they certainly aren't mature enough to be forced to experience the negative consequences of making bad medical decisions on their own," England said. "The double standard in our existing law needs to be addressed."

Bob Allen is managing editor of EthicsDaily.com.