WASHINGTON -- The Supreme Court Tuesday issued a broad ruling limiting presidential power and the reach of international treaties, saying neither President Bush nor the World Court has the authority to order a Texas court to reopen a death penalty case involving a foreign national.

The court held 6 to 3 that judgments of the international court are not binding on U.S. courts and Bush's 2005 executive order that courts in Texas comply anyway does not change that. The decision, written by Chief Justice John Roberts Jr., was a rebuke to the government in a case that involved the powers of all three branches of government, the intricacies of treaties and the international debate over the death penalty.

It placed the president on the side of Ernesto Medellin, a brutal murderer, and the rulings of the International Court of Justice and against the authority of his home state's courts.

Texas's high court had rejected the World Court's judgment that it "review and reconsider" Medellin's conviction because he is a Mexican national and was not advised after his arrest that he could meet with a consular from his country, as the Vienna Convention requires.

Even though the administration disagreed with the World Court' s decision -- and has withdrawn from the international pact that gave it force -- Bush nonetheless issued a memorandum ordering the Texas courts to rehear Medellin's case.

But Roberts wrote that neither the Optional Protocol of the Vienna Convention nor the operative part of the United Nations charter creates binding law in the absence of implementing legislation from Congress.

And he wrote that the government had not made the case that Bush had the power to issue a directive that "reaches deep into the heart of the state's police powers and compels state courts to reopen final criminal judgments and set aide neutrally applicable state laws."

Joining Roberts were the justices who are most consistently conservative: Antonin Scalia, Anthony Kennedy, Clarence Thomas and Samuel Alito Jr.

Justice John Paul Stevens concurred in the case, but for different reasons than Roberts gave. Stevens agreed Texas could not be forced to reconsider the case, but urged it to do so nonetheless, especially because its failure to advise Medellin of his rights "ensnared the United States in the current controversy."

Justice Stephen Breyer wrote in dissent that the court had misread the Supremacy Clause of the Constitution, which says properly ratified treaties "shall be the supreme law of the land" and that the treaties at issue did not need to be implemented by congressional legislation.

"As a result, the nation may well break its word even though the president seeks to live up to that word and Congress has done nothing to suggest the contrary," Breyer wrote. He was joined by Justices Ruth Bader Ginsburg and David Souter.

Roberts said to accept Medellin's argument would make World Court decisions not only binding domestic law but also "unassailable."

Bush's intentions -- to ensure reciprocal observance of the Vienna Convention with foreign governments, protect international relations and show a commitment to international law -- are "plainly compelling," Roberts wrote. "Such considerations, however, do not allow us to set aside first principles."

Frederick Kirgis, a professor of international law at Washington and Lee University, said he was surprised that the court was not more deferential to the president.

"It is a matter of diplomacy, after all, and the president is the chief diplomat, and he has acted," Kirgis said, adding that the reaction of other governments, especially Mexico's, is "certain to be negative."

The Mexican Foreign Affairs Ministry said it regretted the court's decision and its lawyers are reviewing the implications for "other Mexican nationals facing death sentences, in order to determine immediate legal actions to preserve their rights."

The case involved Medellin and 50 other Mexican nationals who have been convicted in U.S. courts.

Medellin, 33, has lived in the United States since he was 3; he speaks and writes English but is still a Mexican national. He was part of a gang that attacked Jennifer Ertman, 14, and Elizabeth Pena, 16, as they walked home from a friend's house. They were raped and murdered, one strangled with her shoestring.

Medellin signed a waiver of his Miranda right to remain silent and confessed within hours of his arrest. But he was not told of his right to talk to the consulate of his country. Medellin did not raise that right during his trial but did in one of his death penalty appeals.

The administration first argued against Mexico, then in 2005 Bush issued his memorandum to the attorney general saying that the United States will "discharge its international obligations ... by having state courts give effect to the decision" of the World Court.

White House press secretary Dana Perino said Bush was disappointed with the decision and is reviewing it to see how it might influence international relations.

I can't wait for Bush to be gone. He is an ass hat!

I'm very glad they can fry the sick perp!!!!

The President, who negotiates international treaty agreements, probably needs to support the agreements, at least offically.

If Mexico decided to execute an American Citizen and Mexico had denied our embassy access to the person, in violation of the Treaty, and the President of Mexico reaffirmed the violation of the treaty, we might see that as a breach of the Treaty Agreement.

I don't think Mexico has a death penalty, so that situation won't happen. (A country with effective death squads can do without the complications of a death penalty, I suppose.)

But fair is fair.