European leaders convened an emergency summit on Iraq Monday evening, their divisions over the need for war thrown into stark relief by the unity of their electorates' hostility to the prospect.
The massive weekend antiwar demonstrations across the continent have clearly strengthened the hand of French President Jacques Chirac and German Chancellor Gerhard Schröder, who have led diplomatic efforts to forestall US war plans.
And marchers in London, estimated at between 750,000 and a million people, have complicated the outlook for British Prime Minister Tony Blair - Washington's firmest European ally - as he seeks to rally his European Union colleagues behind a threat of imminent force against Baghdad.
The demonstrations, which gathered an estimated five million protesters in the most impressive showing of European public opinion for decades - and hundreds of thousands more in America, Australia, and other countries - "will definitely strengthen France, because Chirac can see that these are his armies," says Sergio Romano, a prominent Italian political analyst.
In Italy, where premier Silvio Berlusconi has taken a staunchly pro-American stand, the size of the demonstration is expected to move him away from such a clear position, Dr. Romano suggests. "Where before the emphasis was very much on being with the Americans, now it will shift towards being with the United Nations as master of the game," he predicts.
War against Iraq would be "very difficult" with much of the public opposed to military action, British Foreign Secretary Jack Straw said Monday after the London demonstrations, though he also reiterated that for Iraq, "Time is running out."
Coming on the heels of a UN Security Council debate last Friday, at which French and German pleas to give UN weapons inspectors in Iraq more time won applause, the demonstrations appeared to offer the chance of a slower approach to war. But US officials made clear that the expression of European public opinion would not deter them.
Asked on Fox News Channel on Sunday whether the protests had unnerved the administration, US national security adviser Condoleeza Rice said "no, nothing could be further from the truth."
The marches were, however, likely to encourage EU leaders to seek a compromise position that would lean more towards stressing the need for a UN mandate for a war, and away from supporting US threats against Iraqi President Saddam Hussein.
That would answer the complaints of many of the weekend demonstrators, who are not pacifists but who fear the consequences of a unilateral attack by the United States, supported by a "coalition of the willing" such as Britain and Australia.
"A lot of people who went on the march aren't so much against war per se, as against the general approach to going to war," said Tim Ham, a business consultant who joined the London demonstration with his parents.
"Our objection is more that we are not going through the UN route," he added. "It's the undermining of the global institutions and the unilateral approach that is very much my objection."
A hallmark of the British demonstration - the diversity of the marchers - was also apparent in Rome, Berlin, Madrid and Paris, and in New York, where between 100,000 and 500,000 protesters, depending on who was counting, clogged the streets of Manhattan.
Many, like Marie-Louise Jackson-Miller of Quincy, Mass., marched with other members of their families. "Our whole family is united for peace," she said, as she walked alongside her mother and two daughters. It was wonderful being with so many like-minded people. This march gave me a whole lot of hope."
"I don't believe that the UN, France, Russia, and Germany are going to be able to stop the rush to war. I really think the only thing standing between a war and not having a war is a mass movement. It has to be calculated into the plans of the warmakers" said Deirdre Sinnott, an activist with International Answer, one of the demonstration's organizers.
For most of the New York demonstrators, however, war seemed almost a foregone conclusion, and in London, few expected the government to change its mind either.
Though the success of the London march "has obviously consolidated opposition" to Mr. Blair within his ruling Labour party, "his position would only be at risk if the war went very badly," says Wyn Grant, a professor at Warwick University.
As the demonstrators massed in Hyde Park, Blair told a Labour Party conference in Glasgow that they were showing "a right and entirely understandable hatred of war. "It is a moral purpose and I respect that," Blair added. "But the moral case against war has a moral answer; It is the moral case for removing Saddam. If there are 500,000 on that march that is still less than the number of people whose deaths Saddam has been responsible for. If there are one million, that is still less than the number of people who died in the wars he started."
That call for regime change in Iraq - the first by a European leader - moved Blair even further away from his EU counterparts, who were meeting in Brussels Monday in an effort to paper over the cracks in their positions on a war and salvage their dream of a common foreign policy.
That goal receded further into the distance earlier this month, when eight current and prospective European Union countries came out openly in support of Washington, rebuffing French and German aspirations to speak for Europe as a whole.
Hundreds of thousands of people in cities around the world protested over the weekend against military action against Iraq.
General crowd estimates
Rome: 1 million
Dublin, Ireland: 80,000
Seville, Spain: 60,000
Bern, Switzerland: 40,000
Glasgow, Scotland: 30,000
Copenhagen, Denmark: 25,000
Toulouse, France: 10,000
Cape Town, South Africa: 5,000
Johannesburg, South Africa: 4,000
Dhaka, Bangladesh: 2,000
Kiev, Ukraine: 2,000
Tel Aviv: 2,000
SOURCE: Associated Press
• Material from Mark Rice-Oxley in London, Stacy Vanek Smith and Steven Savides in New York, and the Associated Press was used in this report.