The ruling, in a pair of cases from Oregon and Virginia, was another by the court's conservative majority that has favored the police. Two weeks ago, the court ruled evidence could be used at trial when the police entered a suspect's home illegally by failing to knock and announce their presence.

Chief Justice John Roberts, one of President George W. Bush's two new conservative appointments to the high court, said for the majority that excluding any statements for a treaty violation would be an inappropriate remedy.

Under the convention, which the United States ratified in 1969 and 169 other nations have ratified, U.S. officials must tell foreign nationals of their right to contact their consulates after their arrest. Americans have the same rights in other countries that signed the treaty.

NO DISPARAGEMENT TO THE VIENNA CONVENTION

Roberts said the ruling "in no way disparages the importance of the Vienna Convention" and that diplomatic avenues remain open for any violation.

He said a failure to tell defendants of their treaty rights was unlikely to produce frequent unreliable confessions or to give the police any practical advantage in obtaining incriminating evidence.

He added that the rights of foreign nationals are effectively protected by other existing constitutional and legal requirements, including the right to a lawyer.

The main dissenters were liberal Justices
Stephen Breyer,
John Paul Stevens and
David Souter.

Breyer wrote that the ruling risked "weakening respect abroad for the rights of foreign nationals, a respect that America in 1969 sought to make effective throughout the world."

Breyer added that it increased the difficulties faced by the United States and treaty-signing nations that want to assure fair treatment around the world.

The Oregon case involved Moises Sanchez-Llamas, a Mexican citizen who was convicted of attempted murder and sentenced to more than 20 years in prison for the 1999 attempted murder of a police officer.

Police told him in English and Spanish of his right to remain silent and to have an attorney present, but not that he could contact the Mexican consulate.

In the Virginia case, Honduran national Mario Bustillo is serving a 30-year sentence for the 1997 murder of an 18-year-old man. Bustillo was not advised of his right to seek legal help from the Honduran consulate.

Virginia courts rejected Bustillo's appeal because he had failed to raise the Vienna Convention claim at trial. The high court upheld that decision.

Several legal groups criticized the ruling.

Barbara Bergman of the National Association of Criminal Defense Lawyers said the decision failed to offer any help "to the hundreds of foreign nationals" in the U.S. criminal justice system every year.

Virginia Sloan of the Constitution Project said, "The fairness and accuracy of our criminal justice system may depend on respecting the Vienna Convention."

Cheered on by Iraq war protester Cindy Sheehan, who has moved to Berkeley, the council voted unanimously on Tuesday to have the city attorney review the measure that would appear on the November ballot.

The Berkeley Peace and Justice Commission, which advises the city on civil rights issues, recommended the measure to the council.

The panel accuses the Republican White House of intentionally misleading Congress to justify an unnecessary war in Iraq, pursuing unlawful surveillance programs and permitting torture of detainees suspected of links to terrorism.

Bush and Cheney "have acted in a manner contrary to their trust as President and Vice President of the United States and subversive of Constitutional government, to the great prejudice of the cause of law and justice and to the manifest injury of the People of the United States of America," the commission said in a statement.

Berkeley has seen its politics march steadily leftward since the 1960s, when the Free Speech Movement and Vietnam War protests at the University of California, Berkeley, drew political activists to the city.

Bush received 4,010 votes in Berkeley in the 2004 presidential election, compared with 54,409 votes for Democratic challenger John Kerry.

Republican National Committee spokesman Tucker Bounds said the city council's move was "absolutely out of step with mainstream American voters ... but entirely predictable for liberals in Berkeley."

Berkeley resident Albert Sukoff said he was not surprised by the council's decision.

"I think they overextend themselves and get into things that aren't their business," said Sukoff. "Berkeley has always had a foreign policy, the national one notwithstanding."

The case before the supreme court focused on Salim Ahmed Hamdan, a Yemeni who worked as a body guard and driver for the al-Qaida leader, Osama bin Laden. Hamdan, 36, has spent four years in the US prison in Cuba. He faces a single count of conspiring against US citizens from 1996 to November 2001.

Inmates endure open-ended interrogation and detention at the prison, which has become a symbol of the Bush administration's aggressive anti-terror policies.

Mr Bush said last week that he would like to close the camp, but was waiting for direction from the US supreme court. "I'd like to end Guantánamo. I'd like it to be over with," he said after meeting European leaders in Vienna last Wednesday.

Two years ago, the court rejected Mr Bush's claim to have the authority to seize and detain terrorism suspects and indefinitely deny them access to courts or lawyers. In this follow-up case, the justices focused solely on the issue of trials for some of the men.

More than 750 inmates have passed through the steel mesh cages of Guantánamo.

Its numbers of prisoners, however, have been reducing, with no new detainees arriving since September 2004. There are currently around 460 inmates and the Pentagon has already said it intends to transfer 120 of these to their home countries.