Facing certain defeat in the Security Council, the United States, Britain and Spain withdrew their joint resolution that sought U.N. authorization for a war to disarm Iraq and instead fell back on an earlier Security Council resolution that they insisted was sufficient to justify forcibly toppling Saddam Hussein's regime.

But that diplomatic shuffling could not mask the irony noted by dispirited international envoys here: that a war President Bush has long insisted is necessary to restore the Security Council's legitimacy will now be fought without the Security Council's endorsement.

The failure of the Security Council to reach consensus on the best way to disarm Iraq, and the bitter schisms that cracked open between Washington and some of its strongest European allies over the issue, together carry worrying implications for the world body's future relevance in matters of war of peace. In the new world order dominated by the overwhelming power of the United States, the United Nations faces being relegated to a largely humanitarian role.

"I think the time for diplomacy has passed," conceded Secretary of State Colin Powell, declaring an epitaph to his efforts over the last six months to forge agreement in the Security Council on confronting Hussein.

But the Bush administration's failure to persuade much of the world of the merits of its case against Iraq, and its ensuing decision to bypass U.N. approval for a war, carry implications of their own. Critics at home and abroad fear that this first "preventive" war conducted under the Bush administration's doctrine of pre-emptive strikes against potential threats may portend a new era of even greater world instability unmitigated by any international mediating force.

A U.S.-led war against Iraq "will not only bring about human casualties but also destabilize the international community in general," declared Russian President Vladimir Putin, breaking weeks of studied silence on the crisis.

There was no shortage of blame Monday for the diplomatic breakdowns, and it was expressed in distinctly undiplomatic terms.

Washington and London pointed fingers at Paris and its insistence on ruling out the use of force in favor of extending U.N. weapons inspections.

By its vow to veto any Security Council resolution authorizing war, France "inevitably created a sense of paralysis in our negotiations," British Foreign Secretary Jack Straw told his nation's Parliament. "And I deeply regret that France has thereby put Security Council consensus beyond reach."

French Foreign Minister Dominique de Villepin shot back that the U.S., Britain and Spain had decided to abandon diplomacy when it became clear they could not prevail at the UN.

"Despite the will clearly expressed by the international community, the United States, Britain and Spain underlined today their determination to resort to force," de Villepin said in a statement. France "regrets a decision that is not justified today and that risks serious consequences for the region and the world."

Even U.N. Secretary General Kofi Annan, who has been reluctant to insert himself directly into the Iraq debate, criticized the collapse of Security Council diplomacy. He contended that if war is launched "without the support of the council, its legitimacy will be questioned and the support for it will be diminished."

Germany's U.N. ambassador said he thought there was still a "1 percent chance" that diplomacy could avert war when the Security Council meets again on Wednesday to hear a report from the chief weapons inspectors on key remaining disarmament tasks. But with Annan ordering all U.N. inspectors and other humanitarian workers out of Iraq for their own safety, most other diplomats said further Security Council debate appeared moot.

For his part, Powell sought to deflect accusations that American diplomacy had faltered because he had failed to travel extensively and conduct the kind of face-to-face coalition-building his predecessor James Baker had pursued in the run-up to the 1991 Persian Gulf war.

"I believe that I have used my time properly," Powell told reporters, recounting a series of meetings and phone calls he had with foreign leaders in recent weeks. " ... I travel when I believe travel is appropriate."

Another Powell predecessor, Madeleine Albright, suggested the blame lay with administration hawks, such as Vice President Dick Cheney and Defense Secretary Donald Rumsfeld, who had been urging a war against Iraq since shortly after the Sept. 11, 2001, terrorist attacks.

"There was a group that did not want to see diplomacy succeed," Albright, who served in the Clinton administration, said on CNN. "All of a sudden, the U.S. has put itself above every kind of institution that has been the basis of international relations for 50 years."

But one of those hawks, Pentagon adviser Richard Perle, asserted recently that the United States must be willing to go it alone in the world if its security is threatened.

"The U.N. didn't protect us on Sept. 11," Perle told the American Enterprise Institute last month. "There's not a lot of reason to believe that international institutions are going to protect us from the next terrorist attack. So there's been a sobering reaction to multilateralism."

Just two weeks ago, Bush had vowed to demand a Security Council vote on a new Iraq resolution and force each of the 15 nations to show its cards no matter what the "whip count" showed. But as it became clear that the White House could count on only four votes in favor, administration officials decided against pursuing a war in the face of an explicit Security Council rejection.

Instead, they argued that numerous Security Council resolutions demanding Iraqi disarmament over the past 12 years, capped by last November's unanimous resolution threatening Iraq with "serious consequences" if it failed to comply, provide sufficient justification for the use of force. Moreover, Bush has said repeatedly, ending Iraqi defiance is necessary to maintain the credibility of the Security Council.

By withdrawing the doomed resolution, Washington also avoided forcing an open confrontation with Russia and China, each of which had hinted at a potential veto, or with other essential U.S. allies such as Chile, Mexico and Pakistan, which had been leaning toward voting no.

This will scarcely be the first time a nation has waged war without U.N. approval. Among other examples, Washington did it in Vietnam, Grenada and Panama; Britain in the Falklands; and the former Soviet Union in Afghanistan. In the 1990s, the Security Council failed to take action to stop either the genocide in Rwanda or the fighting in Kosovo. In the latter case, the Clinton administration invoked NATO to enter the conflict and halt the attacking Serbs.

But proceeding without a U.N. mandate carries grave risks, critics assert.

"All the threats to the U.S. today are transnational threats, meaning weapons of mass destruction, terrorism, AIDS, global warming," said Judith Kipper, a Middle East expert at the Center for Strategic and International Studies in Washington, D.C. "They all require a multilateral approach. The U.N. Security Council is the vehicle that makes multilateral approaches possible. And it is now broken. This has been nothing short of a diplomatic catastrophe."