The United States initially backed the measure as a means to protect its citizens abroad. It was also the first country to invoke the protocol before the ICJ, also known as the World Court, successfully suing Iran for the taking of 52 U.S. hostages in Tehran in 1979.

But in recent years, other countries, with the support of U.S. opponents of capital punishment, successfully complained before the World Court that their citizens were sentenced to death by U.S. states without receiving access to diplomats from their home countries.

The Supreme Court is scheduled to hear oral arguments March 28 in the case of a Mexican death row inmate in Texas who is asking the justices to enforce an ICJ decision in favor of Mexico last year. That case has attracted wide attention in Mexico and caused a diplomatic rift between the Bush administration and the government of Mexican President Vicente Fox.

Rice is scheduled to meet with Fox today in Mexico in preparation for a summit meeting at President Bush's ranch in Crawford, Tex., later this month.

The administration's decision does not affect the rest of the Vienna Convention, which requires its 166 signatories to inform foreigners of their right to see a home-country diplomat when detained overseas. But it shows that Washington's desire to counteract international pressure on the death penalty now weighs against a long-standing policy of ensuring the United States a forum in which to enforce its citizens' allegations of abuse.

"The International Court of Justice has interpreted the Vienna Consular Convention in ways that we had not anticipated that involved state criminal prosecutions and the death penalty, effectively asking the court to supervise our domestic criminal system," State Department spokeswoman Darla Jordan said yesterday.

Withdrawal from the protocol is a way of "protecting against future International Court of Justice judgments that might similarly interpret the consular convention or disrupt our domestic criminal system in ways we did not anticipate when we joined the convention," Jordan added.

The administration's action comes after its Feb. 28 decision to grant 51 Mexicans on death row in Texas and elsewhere new state court hearings, as the ICJ had ordered.

But withdrawal from the protocol means that the United States will not have to bow to the ICJ again, legal analysts said.

Some said the decision would weaken both protections for U.S. citizens abroad and the idea of reciprocal obligation that the protocol embodied.

"It's encouraging that the president wants to comply with the ICJ judgment" in the Mexicans' case, said Frederic L. Kirgis, a professor of international law at Washington and Lee University. "But it's discouraging that it's now saying we're taking our marbles and going home."

The State Department, however, notes that fewer than 30 percent of the signatories to the Vienna Convention had agreed to the protocol. Among those that had not done so are Spain, Brazil and Canada, officials said.

Bush's decision to enforce the ICJ judgment in the case of the Mexicans "should ensure that our withdrawal is not interpreted as an indication that we will not fulfill our international obligations," said Jordan of the State Department.

Meanwhile, the president's decision has thrown the Supreme Court case regarding the Mexicans into limbo. Some legal analysts suggest the case may now be moot.

Attorneys for Jose Ernesto Medellin, a convicted murderer on death row in Texas who is seeking review of his assertion that a lack of consular access harmed his case at trial, have asked the justices to put the case on hold until after Medellin has had his hearing in Texas state court.

The Texas attorney general's office, meanwhile, issued a statement Tuesday saying, "We respectfully believe" that the president's decision "exceeds constitutional bounds for federal authority."