As he urged closer ties with Europe Monday, President Bush played down the current political disputes. "No power on earth will ever divide us," he said.
That may be true when it comes to Iran's nuclear program. But his remark ironically hints at a transatlantic chasm over US and European values, and the role each side assigns to a fundamental facet of human life: religious faith.
Two events last year neatly frame the challenge: In the United States, a California man tried to remove "One Nation, Under God" from the Pledge of Allegiance. Americans cried foul - roughly 90 percent wanted to keep the phrase - and on June 15, the Supreme Court halted the bid on procedural grounds.
Three days later, in Brussels, officials agreed on the final text of the European Union's new Constitution. The charter made no mention of God, despite calls that it recognize Europe's Christian roots.
Indeed, its secularism has led to jokes that Europe is one big "blue" state. But Europeans aren't laughing. Buffeted by the crosscurrents of secularism, Christianity, and Islam - and mindful of a history of religious violence - they are wrestling with their values and identity as never before.
"The clash between those who believe and those who don't believe will be a dominant aspect of relations between the US and Europe in the coming years," says Jacques Delors, a former president of the European Commission. "This question of a values gap is being posed more sharply now than at any time in the history of European-US relations since 1945."
Religion's role in public life, and its influence on politics, have been center-stage questions worldwide since Sept. 11, 2001. But the debate in Europe has been complicated by the continent's difficulty in integrating its fast-growing Muslim immigrant minority. It has been sharpened by tragedies such as the bombing of a Madrid train station last March, and the brutal murder of Dutch filmmaker Theo van Gogh by an Islamic extremist last fall.
Those incidents "will reinforce secularism" in Europe, predicts Patrick Weil, a sociologist of religion at the Sorbonne in Paris. "The tendency now in Europe is to say we have to be clear on the limits to religious intervention" in public life. "We are not going to sacrifice women's equality, democracy, and individual freedoms on the altar of a new religion."
Secularists who think like that are swimming in friendly waters in Europe, where religious convictions and practice have dropped sharply in recent decades, and where mainstream churches - especially the Catholic Church - continue to lose members and influence.
Today, just 21 percent of Europeans say religion is "very important" to them, according to the most recent European Values Study, which tracks attitudes in 32 European countries. A survey by the Pew Forum on Religion and Public Life found that nearly three times as many Americans, 59 percent, called their faith "very important."
Although a Gallup poll found last year that 44 percent of Americans say they attend a place of worship once a week, the average figure in Europe is only 15 percent, although the picture varies widely across the Continent. (See map.)
For some Europeans, that slump marks a defeat for moral values at the hands of godless secularism.
"The new soft totalitarianism that is advancing on the left wants to have a state religion," complains Rocco Buttiglione, the Italian politician whose ambition to become the European commissioner for justice was thwarted last year by the European Parliament, which objected to his description of homosexuality as a sin.
"It is an atheist, nihilistic religion - but it is a religion that is obligatory for all," Mr. Buttiglione adds.
Luis Lopez Guerra, the Spanish government's point man in its campaign to wrest from Catholic influence social legislation on questions such as abortion, divorce, and gay marriage, sees things differently.
He wonders why, in a country where less than half the population ever goes to church, he should have found a Bible and a crucifix on his desk, along with the Constitution, when he was sworn in as undersecretary at the Ministry of Justice a year ago.
The Spanish government's plans to legalize gay marriage this spring, to liberalize divorce and abortion laws, and to permit stem-cell research, do not represent an attempt to impose an atheist state religion, he insists. Rather, he says, they "extend civil rights and make the law independent of Catholic dogma.
He adds, "The government has a responsibility to represent the majority of the people. Our policy has to depend on the people's will, not on the preferences of the Catholic church."
Spain is currently the front line in the Vatican's rear-guard battle to retain church influence over public policy in Europe. But with public opinion ranged firmly on the government's side, there seems little it can do but make its displeasure known.
Pope John Paul II lashed out at Madrid recently, accusing authorities of "restriction of religious freedom" and "relegating faith to the private sphere and opposing its public expression."
The changes in Spain, Catholic church leaders worry, are part of a broader trend. Cardinal Renato Martino, head of the Pontifical Council for Justice and Peace, recently attacked "a new holy inquisition ... motivated predominantly by prejudice toward all that is Christian."
Other traditional churches have felt the same cold winds. The president of the French Protestant Federation, Jean-Arnold de Clermont, warned Prime Minister Jean-Pierre Raffarin last December of a climate of "secularist zeal" that was undermining all faiths.
Such zeal has known peaks and troughs over the centuries, but it is not new to Europe, where political leaders and ordinary citizens experienced religion and felt its weight in ways quite unknown to Americans.
The differences are rooted in the 18th century, when the Enlightenment, the philosophical revolution that laid the foundations of the modern Western world, was interpreted quite differently by Americans and Europeans in one crucial respect.
In Europe, says Grace Davie, an expert on religion at Exeter University in England, "the Enlightenment was seen as freedom from religion ... getting away from dogma, whereas in the [US] it meant freedom to believe."
In America, a country founded in part by religious dissidents fleeing an oppressive government, "religious groups are seen as protecting individuals against the interference of the state," says Mr. Weil.
In Europe, on the other hand, the post-Enlightenment state "is seen as protecting individuals from the intrusion of religious groups," Weil argues, after centuries during which the official church, be it Catholic or Protestant, had always been closely identified with temporal powers.
While religion and democracy have always been intertwined in America, where churches were at the forefront of battles against slavery and in favor of civil rights, this has by no means been the case in Europe. There, estab-lished churches in countries such as Spain and France long opposed political reform.
European mistrust of public religion is heightened even further, however, when it is mixed with patriotism in the kind of rhetoric that President Bush often uses.
"God and patriotism are an explosive mixture," cautions Nicolas Sartorius, an éminence grise of the Spanish left who spent many years in jail during Gen. Francisco Franco's dictatorship. The dictator's guiding ideology, he recalls pointedly, was known as "Catholic nationalism."
After a tortured, centuries-long history of wars fought over religion, in whose name millions died, Europeans are deeply skeptical today of patriotic exhortations infused with religious meaning, says Karsten Voigt, German Chancellor Gerhard Schröder's adviser on relations with Washington.
And nowhere is this truer than in Germany, he adds. "The mixture of patriotism and religion is anathema and heresy in German religious life because it was misused and went too far in the past," Mr. Voigt explains. "Remember, German soldiers in World War I wore belt buckles reading 'Gott Mitt Uns' [God With Us]."
Dominique Moisi, one of France's most respected political analysts, agrees. Viewed from this side of the Atlantic, "the combination of religion and nationalism in America is frightening," he says. "We feel betrayed by God and by nationalism, which is why we are building the European Union as a barrier to religious warfare."
EU members have gone further than any other group of nations in pooling their national sovereignty in the interests of collective security. It's a concept completely foreign to the US, where Bush has repeatedly insisted that he will do whatever he sees fit to protect Americans.
That divergence "is a matter of principle, a matter of values," says Martin Ortega, an analyst at the EU's Institute for Security Studies in Paris. "Europe's history has led Europeans to a more cosmopolitan worldview, which tries to understand 'the other,' " he suggests.
One of the implications of this approach, Mr. Ortega argues, is that a ban on the use of force except in extreme circumstances has become a European value, just like its corollary: reliance on international law.
That, too, sets Europe apart from America in a fundamental way when it comes to coping with world crises.
The differences were stark over the war in Iraq. They persist with regard to Iran, where Europe's three largest nations are pursuing diplomatic efforts to prevent Iran from enriching uranium - efforts the US has refused to join.
The values gap is evident in Washington's wariness of multilateral approaches to world affairs: The US has rejected the Kyoto treaty, designed to slow global warming, which came into force last week, while the EU embraced it. And Europe supports the International Criminal Court, which the US opposes.
Some European leaders, eager to mend diplomatic fences with the US, fear that such different perspectives could tempt Washington to dismiss Europe as an unreliable ally.
"In some segments of conservative US opinion, anti-European feeling is on the rise," worries Mr. Voigt. "They see us as soft on terrorism, or as simply immoral."
On the contrary, retorts Ortega, who describes himself as a Catholic believer, "I interpret my religion in a more modern, humane, and universal manner. I find the American manner quite antiquated. For example, I'm sure that when President Bush applied the death penalty in Texas, or decided to use force in Iraq, he felt it compatible with his religious beliefs."
In fact, the fundamental values that Europe and the US proclaim are almost identical.
Few Americans would quibble over the proposed EU Constitution's declaration that "the Union is founded on the values of respect for human dignity, freedom, democracy, equality, the rule of law and respect for human rights." It goes on to promote "tolerance, justice, solidarity, and equality between women and men."
These shared sentiments, however, flow from different metaphysical head waters. In his inaugural address last month, Bush founded his commitment to human rights on the belief "that every man and woman on this earth ... bear[s] the image of the Maker of Heaven and Earth."
That thinking does not sit well in Europe, where human rights are rooted in a tradition of secular humanism, which holds that mankind is capable of ethical conduct and self-fulfillment without recourse to the supernatural.
In Europe, secularism is not understood as necessarily hostile to religion. In France, the term denotes a level playing field, on which the state allows all religions to operate freely, but stands aside. Elsewhere, it means an indifference to faith. More generally, secularism refers to an approach to life grounded not in religious morality but in human reason and universal ethics.
At the same time, European governments have chosen to adopt a broader set of moral values in setting their foreign policy than they see apparent in US policy, which to them often seems wholly focused on "the war on terror."
That leads them to attach more importance to issues such as the en-vironment and poverty, as British Prime Minister Tony Blair and French President Jacques Chirac stressed in speeches to the World Economic Forum in Davos, Switzerland, earlier this month.
Though the broad moral values at the foundations of public policy in Europe draw clearly on Christian inspiration, the established churches are equally clearly losing their grip on social attitudes to personal moral questions.
A look at the dramatic fall in birthrates all over Europe reveals how faithfully couples are following Catholic teaching on contraception. And as religion's importance fades in people's lives, their permissiveness increases, the European Values Study found.
For example, of the 10 countries where religion is most important to people's lives, eight are among the 10 least tolerant of euthanasia. An increasing number of European governments are following Britain's lead in legalizing stem-cell research, with public support, despite opposition from Catholic leaders.
But even if churches are emptying across Europe, and citizens are reluctant to imbue policy with religious significance, that hardly makes the Continent atheist, pollsters and religious leaders say.
Rather, suggests Archbishop John Foley, the US head of the Vatican's Council for Social Communications, "many people in Europe consider it poor taste to mention your beliefs. It is perceived as rendering other people uncomfortable."
While only 41 percent of Europeans say they believe in a personal God, another 33 percent believe in a spirit, or life force.
It is on that reservoir of spirituality that religious leaders of several faiths hope to draw, in order to bring religion back from the margins of public life in Europe. And they are finding encouragement from some unlikely sources.
In France, perhaps the most militantly secular society in Europe, and which this year celebrates the 100th anniversary of a law separating church and state, one of the men most likely to succeed Jacques Chirac as president broke a strict political taboo late last year.
In a book-length series of interviews entitled "The Republic and Religion: Hope," Nicolas Sarkozy, the president of the ruling conservative Union for a Popular Movement, broached controversial subjects such as state funding for religious institutions.
He was motivated by a feeling that would be banal in the US, but which for a French political leader is almost revolutionary: "That the religious phenomenon is more important than people think, that it can contribute to peace, to balance, to integration, to unity and dialogue," he wrote. "The Republic should debate this, and reflect on it."
• Sophie Arie in Rome and Mark Rice-Oxley in London contributed to this report.