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World opinion and a countervailing U.S. death penalty policy collided once again at the Supreme Court (search).

Just one month ago, the high court outlawed the death penalty for juvenile criminals in a bitterly divided 5-4 decision, citing in part the strong weight of international sentiment against it.

This time, justices were asked to determine the role of international law in U.S. courts in the case of Jose Medellin, a Mexican national who says he was denied access to legal help from his consulate on a rape and murder charge in violation of a U.S. treaty.

Medellin says he is entitled to a federal court hearing based on a violation of the Constitution's clause making treaties the "supreme law of the land."

In their comments from the bench Monday, several justices seemed reluctant to decide who has final say over interpreting that treaty — state or federal courts, the U.S. president or an international tribunal — after President George W. Bush (search) last month ordered new state court hearings for Medellin and 50 other Mexicans on death row.

"Isn't it true that the Texas proceeding could make this moot?" asked Justice John Paul Stevens (search). "We may be engaged in a lot of useless actions."

But Chief Justice William H. Rehnquist, appearing in his second week of arguments after a five-month absence from the bench due to thyroid cancer, wondered whether delaying the case after Bush's unexpected move would send the wrong message that justices endorsed his actions.

"I think granting a stay would be seen as validating the position of the government without having any opinion on it," he said.

Medellin was one of five gang members sentenced to death by a state court for raping and murdering Jennifer Ertman, 14, and Elizabeth Pena, 16, in Houston in 1993. Under the 1963 Vienna Convention, which the Senate ratified in 1969, Medellin was entitled to notify Mexican diplomats when he was arrested.

It wasn't until four years later, after his death sentence was affirmed by a Texas appeals court, that Medellin learned of that right. Texas now contends that Medellin's claim is barred in federal court because he failed to raise that objection at the state trial.

The case, which has attracted worldwide attention, is seen as a test of how much weight the Supreme Court will give in domestic death penalty cases to the International Court of Justice, or ICJ, in The Hague, which ruled last year that the 51 convictions violated the Vienna Convention.

After Medellin appealed to the Supreme Court, Bush ordered the states to comply with the ICJ ruling. At the same time, however, he made clear that it was a president's — not the judicial branch's — decision whether to abide by international law.

The administration also announced it was withdrawing from a section of the Vienna Convention that gave the ICJ authority to hear U.S. disputes, to avoid future questions about the role of international tribunals in domestic death penalty cases.

After Bush ordered the new hearings, Medellin's attorneys asked the Supreme Court this month to put his case on hold so they could pursue relief in state court first. But the justices did not immediately act on that request.

During arguments Monday, attorneys for the Bush administration and Texas urged the court to rule that Medellin and other foreigners have no rights in federal courts, even with the ICJ ruling, because of his failure to raise the claim earlier.

An international ruling gives foreigners no additional rights under the U.S. Constitution, and so putting the case on hold — or even dismissing it outright — could hamstring their case since Medellin could raise the issue again if he loses in a new state hearing, they said.

Last year, the New Orleans-based 5th U.S. Circuit Court of Appeals sided with Texas, ruling that federal relief for Medellin was barred because he failed at trial to file objections about consular access. It cited a 1998 Supreme Court case that suggested treaties were subject to each country's procedural rules.

Giving Medellin access to federal court based on an international ruling would have "detrimental consequences" because it would rob the president of his power in foreign affairs to "respond to international tribunals in a manner he sees fit," said Michael Dreeben, U.S. deputy solicitor general.

According to Amnesty International, the Mexicans on death row affected by the ICJ ruling are held in nine states, although some of the punishments were recently reduced to life sentences. The states are California (27); Texas (15); Illinois (3); and Nevada, Ohio, Oklahoma, Oregon, Arizona and Arkansas (1 each).

Medellin is supported in his appeal by dozens of countries, legal groups and human rights organizations, as well as former American diplomats and the European Union.

In all, 118 foreigners from 32 countries are on death rows in the United States.