WASHINGTON - Impasses at the United Nations and within the Atlantic alliance, combined with large anti-war demonstrations around the world yesterday, have created a broad challenge to President Bush's ability to wield American power, including the possible use of military force.
The challenge presents Bush with tough decisions concerning the timing of a war in Iraq and how he will handle other international crises, such as North Korea's nuclear program and the war on terrorism.
While some European countries have long been wary of America's position as the world's lone superpower, the Iraq crisis has brought this undercurrent of distrust to the surface and cast France in a leading role among nations seeking to block action against Iraqi President Saddam Hussein by the United States.
"There's a profound disagreement over Iraq policy that takes place within the larger disquiet over this administration's use of American power," Ivo Daalder, a foreign policy analyst with the Brookings Institution, said yesterday.
Opponents of war against Iraq sought last week to use levers of the international security system - which the United States led the way in creating a half-century ago - to check what they see as unbridled American power.
Yesterday, these efforts were backed by large anti-war demonstrations in New York, London and other cities around the world.
At the U.N. Security Council, veto-wielding members France, Russia and China rebuffed Secretary of State Colin L. Powell's argument Friday that Hussein had stymied U.N. efforts to disarm Iraq peacefully and that the council must contemplate authorizing military action.
At NATO, France, Germany and Belgium blocked an American request to plan assistance for Turkey in the event that Iraq responded to an American-led invasion by launching attacks against its neighbor, a NATO member that has agreed to be host to American troops in the event of a war.
Belgian Prime Minister Guy Verhofstadt underscored Europeans' aim of slowing the march to war yesterday, even as he offered a NATO compromise that could allow the alliance to plan for assisting Turkey. The three nations would support such aid, he said, if NATO makes clear that the action is defensive in nature. The alliance has scheduled an urgent meeting today of the ambassadors of its 19 member states to discuss the proposal.
The point of the compromise, Verhofstadt said, was to "avoid above all that this decision is a first step in a buildup to war."
The strong anti-war sentiment called into question whether the United States can effectively use international organizations in combating threats the Bush administration sees emerging from a combination of terrorists and rogue states with weapons of mass destruction.
Faced with the collapse of international unity, an administration official said Friday that the Bush administration must decide whether it should even try to rally support in the U.N. Security Council behind a new anti-Hussein resolution or abandon the effort.
"I'm not sure we'll do it next week or do it at all," the official said.
Bush has repeatedly said that if the United Nations is unwilling to take the steps necessary to disarm Iraq, he will lead a coalition of nations willing to do so.
Last week, he called on "free nations" to show backbone and courage and not allow the United Nations to "fade into history as an irrelevant debating society."
Timing could play a big role in Bush's decision on whether to spurn the United Nations. Military planners say that early next month would be the optimum time for launching an invasion, given the added hardships that would be imposed on troops fighting in the desert heat of the late spring and summer.
But Bush, in his calculations, will likely have to weigh the difficult consequences of going to war without explicit U.N. authority.
Lack of Security Council support imposes added political risks on British Prime Minister Tony Blair, who faces strong opposition to war within his own Labor Party. It could also cause serious domestic problems for the leaders of Turkey and U.S. allies in the Arab world, all of whom face strong domestic opposition to a war and hope a council resolution will give them political cover for assisting the United States.
Bush also has to weigh whether acting without U.N. approval would diminish chances of other wealthy nations' joining to help rebuild and stabilize Iraq after a war.
An array of nations has supplied soldiers and money to help restore stability to Afghanistan, reducing the need for a large number of U.S. troops to remain in the country and reducing the strain on the American taxpayer. Iraq is likely to require an even bigger international commitment if the United States wants to avoid a long and costly occupation.
A further calculation is whether defying the wishes of other major world governments will cause them to lessen their diplomatic, law enforcement, financial and intelligence cooperation with the United States in the continuing war to dismantle al-Qaida's terrorist network, operating in scores of countries around the world.
A decision to go to war outside the U.N. framework may also have repercussions for America's ability to enlist international help in confronting other threats, including the suspected ambitions of both Iran and North Korea to become nuclear powers.
The split in the United Nations over Iraq came in the same week that the United States pressed for the world body to assume responsibility for the crisis over North Korea's nuclear weapons program.
In the case of North Korea, U.S. officials have sought to avoid a "go it alone" policy, instead insisting that the job of persuading Pyongyang to abandon development of nuclear weapons must be shared by the international community as a whole. The aim of turning the problem over to the Security Council last week was to bring world pressure to bear on North Korea, which until now has insisted on negotiating only with the United States.
Testifying before Congress last week, Powell said, "We have to have a regional settlement. It can't just be the U.S. and the DPRK [Democratic People's Republic of Korea]."
The United States also registered alarm last week over Iran's announcement that it is mining uranium and is about to produce nuclear fuel. The State Department said the announcement "raises serious questions about Iran's supposedly peaceful nuclear program."
The Associated Press contributed to this article.