Christopher Hitchens -- bald from cancer treatments, speaking between doctor's appointments -- has a special disdain for deathbed religious conversions. Appearing before a group of journalists organized by the Pew Forum on Religion and Public Life, he criticized the pressures put on Tom Paine to embrace Christianity and the malicious rumors of faith that followed Charles Darwin's demise. "I've already thought about this a great deal, thanks all the same," he explained. The idea "that you may be terrified" is no reason to "abandon the principles of a lifetime." At this event -- a joint appearance with his brother Peter, a Christian -- Hitchens applied those principles with typical vigor. His arguments on the political dangers of religion are strong. In Turkey or Russia, he notes, " 'faith-based' is not a preface to something positive." In Iraq or Iran, a "secular" ruler would be cause for celebration. The alliance of faith and power is often unholy.

But Christopher Hitchens is weaker on the personal and ethical challenge presented by atheism: Of course we can be good without God, but why the hell bother? If there are no moral lines except the ones we draw ourselves, why not draw and redraw them in places most favorable to our interests? Hitchens parries these concerns instead of answering them: Since all moral rules have exceptions and complications, he said, all moral choices are relative. Peter Hitchens responded, effectively, that any journey becomes difficult when a compass points differently at different times.

The best answer that Christopher Hitchens can offer to this ethical objection is himself. He is a sort of living refutation -- an atheist who is also a moralist. His politics are defined by a hatred of bullies, whether Kim Jong Il, Saddam Hussein or the mullahs in Iran. His affections are reserved for underdogs, from the Kurds to Salman Rushdie. The dreams of totalitarians are his nightmares -- what W.H. Auden described as: "A million eyes, a million boots in line/Without expression, waiting for a sign." Even Hitchens's opposition to God seems less a theological argument than a revolt against celestial tyranny.

All this fire and bleeding passion would seem to require a moral law, even a holy law. But Hitchens produces outrage, empathy and solidarity without it.

At close range, the pitiless controversialist is kind to people he could easily humiliate -- a category to which most of us belong. The ferocious critic of Christianity accepts and seeks the company of Christians. Friendship is a particular talent. One review of his memoir, "Hitch-22," described it as "among the loveliest paeans to the dearness of one's friends . . . I've ever read." In earlier times, without derision or irony, this would have been called "humanism," a delight in all things human -- in wit and wine and good company and conversation and fine writing and debate of large issues. Hitchens's joy and juice put many believers of my acquaintance to shame -- people for whom religion has become a bloodless substitute for life. "The glory of God," said St. Irenaeus, "is man fully alive." Hitchens would hate the quote, but he proves the claim.

Hitchens's career, character and illness have led to an unexpected development -- unexpected, one suspects, particularly by him. While he remains unmellowed, he has seen a flood of affection. His disdain for Christianity, his animus for Islam, can still offend. But we admire the vivid, irreplaceable whole.

Hitchens has now been given his most astounding assignment, a visit to what he calls in a Vanity Fair article "the sick country." His account is raw, honest and impressive. He reports "a gnawing sense of waste" and the loss of "chest hair that was once the toast of two continents."

"To the dumb question 'Why me?' the cosmos barely bothers to return the reply: Why not?" He is, in some ways, a particularly reliable, clear-eyed witness -- unclouded by sentiment, free from comforting illusions, even illusions I view as truths. It is like watching a man assault Everest with only a can opener and a Q-tip. There is honor in the attempt. And the longer the assignment continues, the better for all of us.

At the Pew Forum, Hitchens was asked a mischievous question: What positive lesson have you learned from Christianity? He replied, with great earnestness: the transience and ephemeral nature of power and all things human. But some things may last longer than he imagines, including examples of courage, loyalty and moral conviction.

michaelgerson@washpost.com