It can be emotional, spontaneous and contradictory. It has no leader, no platform and no ideology. It varies from country to country in its roots and its manifestations. It doesn't even have an accepted name: Those most strongly identified with it indignantly deny they advocate or practice it.

Still, anti-Americanism, West European-style, is widespread, rising and migrating from its traditional home among left-wing intellectuals, academics and cafe society to the political mainstream, according to analysts, critics and public opinion polls. Countries such as France, Germany and Britain, which for more than five decades have been the closest allies of the United States, are beginning to drift away, propelled by a popular wave of concern, alarm and resentment. The immediate focus might be U.S. policy toward Iraq, but the larger emerging theme is an abiding sense of fear and loathing of American power, policies and motives.

"What shocks someone like me, who's lived here 19 years, is the depth of prejudice and suspicion," said Gary Smith, executive director of the American Academy, a nonprofit institute of advanced studies in Berlin. "People impute the worst possible motives for American behavior. The arguments I'm hearing sometimes are beyond logic, beyond reason."

Even in Britain, the most cherished American ally, Prime Minister Tony Blair felt compelled to defend his support for the United States before a hostile TV audience this past week. Participants derided him as "Vice President" and "the member [of Parliament] from north Texas," dismissed Secretary of State Colin L. Powell's presentation to the U.N. Security Council as "absolutely laughable" and equated President Bush with the Iraqi president, Saddam Hussein.

Scenes of anti-American fervor have become a regular feature of the political landscape. At a recent antiwar rally at Ruskin College in Oxford, England, a packed audience cheered as Ken Nichols O'Keefe, a former U.S. Marine, described the United States as "the most despicable and criminal nation in the world." The recent World Economic Forum in Davos, Switzerland, where the elite met to ponder global issues, morphed into a six-day critique of the Bush administration. After one rancorous session, Sen. Joseph R. Biden Jr. (D-Del.) -- no ally of the Bush administration -- pronounced himself "sick and tired of the lectures. In each of your hearts you know we aren't as bad as you make us out to be."

Some analysts insist that anti-Americanism, like anti-Europeanism in the United States, is nothing new. In 1953 Jean-Paul Sartre, the French philosopher, spoke for European leftists of many generations when he said the United States suffered from "rabies." Others dismiss America as shallow and insignificant. "Scratch an anti-American in Europe," Denis MacShane, Britain's minister for Europe, said recently, "and very often all he wants is a guest professorship at Harvard, or to have an article published in the New York Times."

Polls suggest that anti-Americanism as practiced in Europe begins with disagreement with U.S. policies in Iraq and the Islamic world since the attacks of Sept. 11, 2001. But the sentiment quickly broadens to include a more general sense of alienation from American society, which is seen as gluttonous and greedy. The Pew Research Center has reported that while most people say they admire American movies, music and television programs, they dislike the spread of American ideas and customs.

The rancor directed across the Atlantic today comes as Europeans are struggling to agree on common economic and foreign policies. They are divided over the very size and definition of the European Union, and over how far Europe should go in developing a defense capability. Into this vacuum comes a Bush administration whose self-assured policies and rhetorical style smack to many Europeans of unilateralism and arrogance.

"The Americans are pushing their weight around and doing it with rhetoric that may go down well in some parts of the U.S. but rubs us the wrong way all of the time," said Christoph Bertram, research director of the German Institute for International and Security Affairs. "And the fact we're aware of our continuing dependence on the U.S. doesn't help. It's American power, but also the rhetoric of American power that has exacerbated the sense of weakness, alienation and uneasiness that we see all over Europe."

Recent polls show opposition to war against Iraq at levels of 65 percent and higher throughout Western Europe. And the Pew Center's Global Attitudes Survey of 44 countries in December found growing discontent with the United States throughout the world, with Western Europe just behind the Islamic world in its disaffection. In Germany and France, critical assessments of the United States were much more widespread than in the developing nations of Africa and Asia, according to the survey.

Perhaps most telling were suspicions about U.S. intentions. The poll indicated that 75 percent of the French surveyed, 54 percent of Germans and 44 percent of Britons believed a U.S. desire to control Iraqi oil was the United States' principal reason for considering a war. The numbers might help explain why Powell's U.N. presentation, which generally went over well with Americans, had little impact on Europeans.

Smith, the director of the American Academy, recalled the prosperous and sophisticated German couple who sat next to him on a recent train ride to Berlin. Creators of a successful pharmaceutical research company, they were the kind of people he assumed would be most comfortable with American ideas and values. Instead, he said, they railed against American arrogance and imperial ambitions and refused to concede there might be two sides to the argument.

"I was making the case that if we go into Iraq and discover weapons of mass destruction, then the world would come to realize we'd been right," Smith recalled. "And they told me, 'If that happens, it's only because the CIA planted them.' I was floored."

Current anti-Americanism first moved into electoral politics in Germany. Chancellor Gerhard Schroeder, a Social Democrat, seemed headed for defeat when he began trumpeting his opposition to U.S. military action in Iraq and his distaste for the Bush administration's rhetorical style. At first it seemed a risky strategy -- many Germans remain grateful for the U.S. security umbrella that protected them during the Cold War. But analysts said it caught the opposition Christian Democrats off guard. Their weak, uncertain response gave Schroeder an opening he skillfully exploited.

"It worked for Schroeder because the opposition party mishandled it," said Reinhard Buetikofer, spokesman for the Greens, part of the Social Democrats' ruling coalition. "They were unable to show leadership, and people grew anxious."

Even Schroeder was reluctant to push criticism of the United States too far -- when a cabinet minister compared Bush's political tactics to Adolf Hitler's, Schroeder forced her to resign. But while some European leaders dismissed the chancellor's criticism of U.S. policy as a blatant domestic political ploy, it resonated outside Germany. When the Bush administration reacted with undisguised fury -- with Bush refusing to speak to Schroeder and Defense Secretary Donald H. Rumsfeld snubbing the German defense minister at a NATO summit -- the chancellor seemed to become even more popular. "Many people believed Schroeder was speaking for them, giving voice to their fears and concerns," said John Palmer, director of the European Policy Center, a research group in Brussels.

In Britain, Blair has dismissed anti-Americanism as "a foolish indulgence." But aides say he is increasingly aware that the gap between his views and public opinion is widening, and he has launched a major public relations campaign of speeches and television appearances to try to narrow it. The distance he has to go was suggested by a challenge from one member of the studio audience he addressed last week: "I would say to you, Prime Minister, that [if] the war is to get rid of a despotic dictator who has no real democratic mandate, who's very destabilizing, who commits human rights violations -- is Mr. Bush next, perhaps?"

Similar popular sentiment in France helped make a runaway bestseller of a book that claimed the Sept. 11 attacks were carried out not by al Qaeda, but by a right-wing cabal in the U.S. government. The book, published in English as "The Big Lie," was dismissed as crackpot speculation by even the most left-wing of French journalists. But when its author, Thierry Meyssan, expounded his thesis on a popular late-night television talk show, sales took off. The book sold 100,000 copies in 10 days, according to its publisher, Patrick Pasin of Carnot books, and has sold more than 500,000 copies in France and other countries. Meyssan, the proprietor of a small, activist left-wing Web site, has been hailed in France and in the Arab world as a courageous truth-teller up against the American leviathan.

While some observers here have attributed the popularity of "The Big Lie" to France's obsession with conspiracy theories, others see it as one barometer of just how far anti-Americanism has spread into the mainstream. Guillaume Dasquie, a French journalist who co-wrote a book, "The Horrifying Lie," that dismantled Meyssan's claims page by page, said he has seen a marketing study indicating that many of those who purchased Meyssan's book are newcomers to book buying.

"The idea of Americans as victims was too unsettling for many ordinary people," said Francois d'Alancon, chief foreign correspondent for La Croix, a Catholic newspaper. "It contradicted their normal view of the world. But with Meyssan's theory, the Americans are the villains again. They become the ones responsible for these terrible events. It's much more acceptable."

The irony, says Alain Frachon, a senior editorial writer for the newspaper Le Monde, is that, in many ways, the French and Americans have never been closer. Trade and travel between the two countries are at all-time peaks. "More Frenchmen speak English, travel to the U.S. for vacation or to do business," he said. "The practical understanding of what the United States is has never been greater."

In the end, some analysts insisted, it doesn't matter if West Europeans despise U.S. policies, so long as they buy American products, go to American movies, and remain too weak and divided to challenge American hegemony. But others argue that the divide has both short-term consequences -- Washington needs its allies to take part in the prolonged and costly nation-building exercise likely to follow an overthrow of Hussein -- and long-term ones. A United States estranged from its traditional allies would be increasingly isolated and vulnerable, they argue.

This suggests to some that the ties that bind are still much stronger than the sources of division. "There are issues where we disagree, and Iraq is certainly one," says Buetikofer, the spokesman for the Greens. "But Americans should not misunderstand the criticism when they hear it. People may criticize, they may even use words that can sound offensive, but it does not mean they want to break the friendship with the United States."

Protesters gathered in Munich last weekend to send a message to Defense Secretary Donald H. Rumsfeld, who was there for a security conference.Protesters in Munich expressed discontent with President Bush, who is seen by many in Europe as a symbol of U.S. unilateralism and arrogance.Prime Minister Tony Blair has come under criticism in Britain for his steady support of the White House.