James Wood, a writer who himself has lived between the tugs of belief and unbelief, made an eloquent call in the New Yorker last August for "a theologically engaged atheism". Concluding a review of Terry Eagleton's recent attack on Richard Dawkins and Christopher Hitchens, he imagines something "only a semitone from faith [which] could give a brother's account of belief, rather than treat it as some unwanted impoverished relative."

At the American Academy of Religion meeting in Montreal last year, he may have gotten his wish, or something resembling it. Following an apocalyptic sermon from "death of God" theologian Thomas J.J. Altizer, to the podium came the ruffled Slovenian philosopher Slavoj Žižek, a self-described atheist and "materialist through and through", before an audience of religion scholars, theologians, and costumed adherents. He spoke of truths Christianity alone possesses and how Christ's death reveals that "the only universality is the universality of struggle." Atheism, he explained, is true Christianity, and one can only be a real atheist by passing through Christianity. "In this sense, I am unconditionally a Christian", said Žižek.

He is one of several leading thinkers in recent years who, though coming out of a deeply secular and often Marxist bent, have made a turn toward theology. In 1997, Alain Badiou published a study of the apostle Paul, whom he took as an exemplar of his own influential philosophy of the "event". Three years later, Giorgio Agamben responded in Italian with The Time That Remains, a painstaking exegesis of the first ten words of Paul's Letter to the Romans. The purpose of both was not a more enlightened piety, but an inquiry into the texture of revolution. Paul is significant to them because he ushered in, and in the process described, a genuinely transformational social movement.

These atheist theologians speak from a sensation of political atrophy; they're assembling a barricade against the onslaught of global capitalism and the tireless inanity of jingoistic violence. But don't expect to find them wafting into church on Sunday morning. Although believers have welcomed literary theorist Terry Eagleton's critique of Dawkins and Hitchens, at a talk in New York this September, he declared he has nothing to say about prayer and is "presently distant from the institutional dimension" of religion, even if falling short of outright atheism. When I asked him, in a subsequent interview, what he wants of his readers, he replied, "I'm certainly not urging them to go to church. I'm urging them, I suppose, to read the Bible because it's very relevant to radical political concerns."

Yet some "real" theologians are starting to follow this phenomenon with interest, seeing in it an opportunity to rejuvenate their own enterprise. The Anglican John Milbank, in a recent book he wrote with Žižek called The Monstrosity of Christ, said of his co-author, "In an important sense, he bears a theological witness". Searching for political answers, Žižek and the others have unearthed some of the forgotten radicalism of earliest Christianity, and they insist on its relevance today. Yet they also represent a threat to the religious status quo. What does it mean, after all, if atheists are doing theology better than believers?

"Žižek's work is hazardous to the health of cardboard theology and the church on which it rests", says Creston Davis of Rollins College in Florida, who edited and orchestrated The Monstrosity of Christ. "It is time we took theology back out of the hands of business-class freeloaders."

There is in this theological turn, also, a dangerous desire. Nobody seems willing to die for a secular philosophy any more, yet in today's "post secular" religion, blood sacrifice abounds. The suicide bombers and abortion-doctor killers whom we all decry seem able to tap into a well of deep conviction like what brought Paul and other early Christians to be martyred for their faith. A politics capable of organizing people to resist the intrusions of capital and ideology would certainly require that kind of commitment. Theology, perhaps, provides a point of access to these ambivalent powers in human nature and the chance to carefully, thoughtfully mobilize them anew.

"It is clear that liberalism has run out of ideas," adds Creston Davis. Philosophy's turn to theology, he believes, is "a step in the right direction toward taking care of the poor and struggling for a better future for the world."