I n 2007, a few months before the French presidential election, a gleeful Nicolas Sarkozy called the philosopher Bernard-Henri Lévy. André Glucksmann, who had been Lévy’s comrade in the struggles against totalitarianism since the 1970s, had announced in Le Monde that he had had it with the hypocrisies and betrayals of the Left. He was crossing the line and backing Sarkozy, the candidate of the Right he had once opposed.

Sarkozy quickly exhausted his limited supply of small talk and got down to business. "What about you?" he asked Lévy. "When are you going to write your little article for me? Huh, when? Because Glucksmann is fine. But you . . . you, after all, are my friend."

Lévy was embarrassed. He had indeed known Sarkozy for years, and had briefed him before a famous television confrontation with Tariq Ramadan, the leading Muslim Brotherhood apologist in Europe. Sarkozy challenged Ramadan over his support for a "moratorium"–instead of an outright ban–on the stoning of Muslim women found "guilty" of adultery. Soon after their debate, Ramadan moved from France to Britain. Once there, he wasn’t treated as an ideologue for a reactionary movement whose founders had been inspired by European fascism, but was feted by the nominally liberal academics of Oxford University and courted by ministers in the nominally left-of-center Labour government. Was this the European Left Lévy was meant to support?

Nor did Lévy need Sarkozy to tell him (although that didn’t stop Sarkozy from telling him) that Ségolène Royal, the socialist candidate and his leading opponent, had already met one of the leaders of Hezbollah–whose top leader, in 2002, had welcomed the gathering of world Jewry in Israel because it "save[s] us the trouble of going after them worldwide." She also had kind words to say about the sleek efficiency of the Chinese justice system, which condemns up to 10,000 prisoners a year to death. "It’s over, Bernard," Sarkozy told him in effect. "You know it better than I do. The nobility has gone. The altruism fled. All that’s left of the Left is malice and cowardice. Join your friends. Join me."

But Lévy couldn’t. "Personal relations are one thing," he said. "Ideas are another. And no matter how much I like and respect you, the Left is my family." It wasn’t much of an answer–and Lévy knew it. Left in Dark Times is his more considered attempt to explain how the left-liberalism he had dedicated his life to had gone wrong in Europe–and how it could easily be perverted in America as well, if liberals do not heed his warnings.

At first glance, American readers may find it easy to dismiss Lévy. The French leftist culture in which he has flourished will strike most as strange beyond measure. America has no Marxist tradition worth mentioning and no experience of Nazi occupation. The totalitarian temptation of communism which enchanted so many French men and women in the twentieth century never enchanted many Americans. Lévy’s searing assault on the ideology of their successors in twenty-first century France may seem to have little to do with anyone outside Europe.

Lévy adds to the impression of otherness by cutting an exotic figure. I met him when we argued against a motion that "democracy isn’t for everyone" at a debate in London last year. He appeared in the green room in an immaculate white suit, looking every inch the dandy, as beautiful in his way as his wife, the actress Arielle Dombasle, who dazzled by his side. Bob Geldof walked across to talk to him, and as my eyes flitted from Geldof to Lévy and back again, I was hard-pressed to tell which was the rock star and which the philosopher. The audience, exhausted by Iraq, was dead against us when we went on stage, but we swung the meeting around and routed our conservative opponents. I like to think that it was the force of our arguments that won the night, but the spectators may just have been bowled over by Lévy’s glamour.

The celebrity thinker is hardly a feature of American politics–do John McCain and Barack Obama crave the support of the equivalents of Glucksmann and Lévy?

But American readers would be wrong to dismiss Lévy as a glamorous foreigner, for a reason I don’t think many liberals have grasped. Americans on the Left may not thank me for saying so, but they have been lucky in one respect to have had George W. Bush as their enemy. He has united the opposition; he has been the glue that has held men and women with wildly contradictory ideas and aspirations together. Hatred of Bush has given the American Left a new salience and a new power, something it hasn’t had since the early days of the Clinton era, but it has not given it a unified vision.

In January, Bush will be gone, but little else will have changed. A President Barack Obama will still face a psychopathic variant of Islam prepared to murder without limit, an Iran pushing for the bomb, and the newly confident autocracies of China and Russia. If he has the nerve to take them on, he will find that the American leftists or progressives or whatever we are meant to call them these days are nowhere near as united as they now seem. Former allies will soon start raging against him as they raged against his predecessor; in some corners of the movement, the clenching of fists has already begun. The arguments we are having in Europe are about to hit the States. Lévy is worth taking seriously because he forewarns in the hope that his Americans will be forearmed.

The first part of Left in Dark Times explains what Lévy meant when he told Sarkozy that he was still a member of the family of the Left. He sees the best of leftish conscience as a series of responses: the Dreyfusard reflex, which encourages us to defend the individual against church and state; the anti-Vichy reflex, which rejects any version of racism or anti-Semitism; the reflexes of the 1968 protest movement, which opposed authoritarianism and censorship; and finally, an anti-colonial reflex, which revolts against the oppression of one people in the name of another. Lévy knows that from the Dreyfus Affair through the Nazi occupation to 1968, there were many on the French Left who sided with the enemy. But on the whole the causes that inspire him were fought by the Left against the Right.

Not now. As the wily Sarkozy realized, in Europe men and women who believe in universal human rights, the emancipation of women, and freedom from tyranny spend more time fighting leftists than rightists.

What was truly exotic about our debate in London was not Lévy’s tailoring but the fact that our opponents were traditional conservatives. Nine times out of ten, the motion that democracy is not for everyone isn’t sponsored by right-wing, establishment believers in privilege and cultural determinism, but by apparent leftists who regard it an extension of "imperialism" to argue, for instance, that it is always wrong to stone women to death.

What motivates them is anti-Americanism–and here is a second reason why stateside readers should pay attention. Today anti-Americanism is the main, often the sole, defining feature of European leftist opinion. Lévy produces the best analysis I have seen, since Richard Wolin’s 2004 The Seduction of Unreason, of how European liberals are taking over a reactionary idea. In the early twentieth century, fascist and proto-fascist writers were appalled by America’s "unnaturalness," he writes: its rejection of tradition, hierarchy, and organic bonds between people and place; its consumerism, standardization, racial mingling, and mass culture. For good reason, they feared America’s appeal to the European masses. Liberals, by contrast, respected the emancipatory potential of a society built on a social contract rather than racial ideas of blood and soil. Today, it is the leftists of Le Monde Diplomatique who pick up the tropes of the old far right, along with, of course, radical Islamists, and warn that American culture is colonizing our brains, insidiously corrupting innocent Europeans and turning them into the dupes of the supposedly all powerful U.S. corporations. As Lévy says, the only America that most of his comrades want is the isolationist nation of Michael Moore and Pat Buchanan, a far away America; an America that is happy for the rest of the world to go to hell.