WASHINGTON – Louisiana prosecutors asked the Supreme Court on Monday to revisit its recent decision outlawing the death penalty for people convicted of raping children.

The unusual request is based on the failure of anyone involved in the case – lawyers on both sides as well as the justices – to take account of a change in federal law in 2006 that authorizes the death penalty for members of the military who are convicted of child rape.

The court almost never grants such requests, but lawyers for Louisiana said their situation was different because the 5-4 decision written by Justice Anthony Kennedy relied in part on what Kennedy called a "national consensus" against executing convicted rapists.

The ruling on June 25 drew harsh criticism from politicians in Louisiana and other states where executing those who rape children was authorized or under consideration. Presidential contenders John McCain and Barack Obama also said they disagreed with the outcome of the case.

But only in the days following the decision did anyone point out that Congress changed the law and that President Bush signed an executive order in September 2007 that implemented the change. It was first discussed on a military law blog.

Louisiana "regrettably did not know of this federal provision," the state's lawyers wrote Monday. "This was a significant error, for which (Louisiana) accepts full responsibility."

In spite of their mistake, however, the lawyers said the federal law is relevant to the case and should be considered by the court.

The main author of Monday's filing with the court was Georgetown University law professor Neal Katyal, who has previously represented Guantanamo Bay detainees at the Supreme Court.

It is unclear when the justices will take up the request. It takes five justices, a majority of the court, to reconsider a ruling.

The decision in June said executions were too severe a punishment for raping children or other crimes against individuals that do not result in the victim's death.

The ruling struck down laws in Louisiana and five other states and spared the only people in the U.S. under sentence of death for raping children – two Louisiana men convicted of raping girls 5 and 8.

However devastating the crime to children, Kennedy wrote in his majority opinion, "the death penalty is not a proportional punishment for the rape of a child."

The Supreme Court banned executions for rape in 1977 in a case in which the victim was an adult woman.

Forty-four states prohibit the death penalty for any kind of rape, and at least four states besides Louisiana permit it for child rape – Montana, Oklahoma, South Carolina and Texas. There's disagreement over the status of a Georgia law permitting execution for child rape, although Kennedy said in his ruling that it was still in effect.

The court previously barred executions for the mentally retarded and people younger than 18 when they committed murder, citing trends in the states away from capital punishment.

In this case, proponents of the Louisiana law said the trend was toward the death penalty, a point mentioned by Justice Samuel Alito in his dissent.

"The harm that is caused to the victims and to society at large by the worst child rapists is grave," Alito wrote. "It is the judgment of the Louisiana lawmakers and those in an increasing number of other states that these harms justify the death penalty."

But Kennedy said the absence of any recent executions for rape and the small number of states that allow it demonstrate "there is a national consensus against capital punishment for the crime of child rape."

When Congress in 1994 expanded the number of federal crimes that could get the death penalty, it did not include raping a child, Kennedy said.

The case is Kennedy v. Louisiana, 07-343.

AP-WS-07-21-08 2040EDT