WASHINGTON – The Supreme Court will consider today whether American courts are bound by the decisions of the International Court of Justice, a tribunal created by the United Nations and based in The Hague.

Numerous countries from Latin America and Europe are clashing with the Bush administration, Texas and 20 other states, and various conservative legal groups over how to resolve conflicts between American and international law.

The closely watched case of a Mexican national on death row comes as the relationship between foreign courts and the American judiciary is causing increasing concern among the administration and congressional Republicans.

Senator Cornyn, a Republican of Texas, cited today’s case as one impetus for the introduction last week of a resolution in the Senate that would instruct federal courts to avoid looking to international and foreign law when interpreting the federal Constitution.

Mr. Cornyn filed one of many friend-of-the court briefs in the case, arguing that the Constitution reserves the power of judicial review to federal judges, and not to “super-supreme courts.”

The International Court of Justice “suffers from the very evils that the Framers sought to protect the federal judicial system” from; because the judges are elected by the General Assembly and the Security Council of the United Nations, they are apt to “curry favor” with a majority of members of the U.N., he argued.

The dispute arises out of an appeal by a Mexican national, Jose Ernesto Medellin, who was sentenced to death by Texas in 1994 for the violent rape and murder of two teenage girls.

Medellin protests that America violated an international treaty when authorities did not inform him of his right to contact the Mexican consulate when he was arrested.

The government of Mexico contends that it was not informed of his case until after his conviction and a failed appeal.

The treaty signed by President Nixon and ratified by the Senate in 1969, known as the Vienna Convention on Consular Relations, gives foreign nationals the right to contact their countries’ representatives, who frequently provide legal and financial assistance, including translation and lawyers.

The treaty’s Optional Protocol, which America also ratified, allows states to litigate violations of the treaty before the International Court of Justice in The Hague.

In a dramatic 2004 ruling, the international court ruled that Medellin and 53 other Mexicans had a right to have their convictions reviewed by American criminal courts for treaty violations.

A federal appeals court denied Medellin such a review, arguing that it would contradict a Supreme Court precedent from 1998 that said international treaties do not trump state rules, such as those in Texas, that prevent defendants from appealing a conviction based on issues that were not raised at trial.

The Supreme Court’s decision to hear Medellin’s case – and its growing interest in the rulings of foreign courts – has raised concerns that it might consider overruling its own 1998 precedent.

“There is a serious risk … that the Court will ignore Texas law, ignore U.S. law, and ignore the U.S. Constitution, and decide in effect that the decisions of the U.S. Supreme Court can be overruled by the International Court of Justice,” Mr. Cornyn said in a statement.

“I am concerned about this trend. Step by step, with every case, the American people may be losing their ability to determine what their criminal laws shall be – losing control to the control of foreign courts and foreign governments,” Mr. Cornyn added.

Lawyers for Texas also argue that federal law prohibits federal appeals of death sentences unless a constitutional right has been violated. They are backed by the attorneys general of 20 other states and an association of district attorneys.

But the American Bar Association, various human rights groups, former diplomats, and an array of foreign countries agree with lawyers for Medellin, who argue that rights created by treaty are binding and judicially enforceable in American law. “This case is about the willingness of the United States to keep its word,” argued Medellin’s lawyers in a written brief to the Supreme Court.

The Texas lawyers agreed that America should keep its word, but they countered that the task does not rest with the judiciary. “The choice of how to do so, and how to respond to alleged treaty violations, is left to the political branches of government,” they argue.

In a separate brief, the acting federal solicitor general, Paul Clement, argued that rights under the treaty cannot be enforced in court, but only through diplomatic means, such as formal apologies, for example.

Earlier this month, under diplomatic pressure from Mexico, President Bush ordered that the Mexican cases be reviewed. However, the administration insists on retaining the discretion to decide such matters.

In an attempt to head off similar cases in the future, Secretary of State Rice informed U.N. Secretary General Kofi Annan earlier this month that America “hereby withdraws” from the Optional Protocol.

The American Bar Association also backs Medellin’s contention that he would have been better represented in his trial had the Mexican government found him a lawyer. His court-appointed counsel was suspended from practicing law at the time of the investigation and trial and failed to strike jurors who indicated they would automatically impose the death penalty, the group notes.

To date, 166 countries have ratified the convention, making it one of the most widely ratified multilateral treaties in effect, but only 46 nations have ratified the Optional Protocol.

A group of 13 Latin American countries allege a “pattern of treaty violations” by local authorities in America that sets a “dangerous precedent’ for other countries. American officials have brought 10 cases before the international court, they note. The most significant was after the takeover of the American embassy in Tehran in 1979. America obtained a favorable judgment under the Vienna Convention and condemned Iran for ignoring it.

The charge d’affaires at the U.S. Embassy in Iran who was held during the hostage crisis, L. Bruce Laingen, is one of several individuals who filed a brief in the case supporting Medellin, arguing that “if the judgment below is allowed to stand, it is inevitable that U.S. citizens abroad will soon suffer in kind.”