SINCE last week I've been hosting a debate over the virtues of religion between Sam Harris and Mark Oppenheimer. One of our guests in that endeavour has been Damon Linker , who penned a wonderful statement laying out the complexities involved in assessing religion's effects. Mr Linker's new book, " The Religious Test: Why We Must Question the Beliefs of Our Leaders ", focuses on the faiths of America's politicians. He argues that the beliefs of some may not be compatible with our liberal democracy, and that this is something voters should know about before going to the polls. So we should not be shy when asking our candidates about their faith. This week, though, Mr Linker answers some questions, which I posed to him over email, on religion's virtue, the "theocons", atheists and social conservatives.

DiA: Elsewhere on the site we are debating the motion: Religion is a force for good. Let's narrow it down a bit. In America, do you think religion, most notably Christianity, has had a positive affect on our politics and policy?

Mr Linker: As with my answer to the broader question, my answer here falls right down the middle. On the positive side of the ledger, Quakers, Methodists, and members of other Protestant denominations were motivated by their faith to take a risky stand against slavery long before most Americans opposed it. Protestant advocates of the “Social Gospel” helped to inspire such crucially important early 20th-century political movements as Progressivism and the New Deal. Numerous religious groups, especially black Protestant churches in the South, launched the civil-rights movement of the 1950s and 1960s. Catholic activists have worked tirelessly to alleviate poverty while also contributing in decisive ways to the anti-war and anti-death penalty movements of recent decades. And then there is the indisputable connection between piety and philanthropy. As many studies have shown, regular churchgoers of every denomination contribute significantly more of their income to charity than their secular counterparts.

All of this is admirable, but it's not the end of the story. For one thing, many of those on the opposite side of these issues—defenders of slavery, critics of Progressivism and the New Deal, opponents of the civil-rights movement, and supporters of the death penalty—have also appealed to faith. Then there is the fact that at a more fundamental level the comprehensive moral and spiritual truths proclaimed by Christianity can clash with the preconditions of liberal politics. When evangelical homeschoolers treat social and political withdrawal as a preliminary step toward cleansing the nation as a whole of spiritual contaminants, it raises the spectre of theologically-inspired conflict and oppression. When Catholics and Mormons bring into the political realm the authoritarian elements of their faith, it threatens to circumvent norms of democratic deliberation. When evangelical and Pentecostal Protestants denounce the scientific study of nature, they produce a population incapable of acting as thoughtful and informed citizens. When religious groups of every denomination view the nation's politics and history through the lens of divine providence, they promise a false clarity that simplifies and distorts our understanding of the country's actions in the world. When Christian traditionalists attempt to use the law to impose their vision of sexual morality on the nation as a whole, they show that they have failed to comprehend the ineradicably pluralistic character of a modern, liberal society.

So it's a very mixed bag.

DiA: In 2006 you wrote a book called "The Theocons", with the subtitle "Secular America under Siege". Could you briefly explain who the theocons are and whether their influence has waxed or waned since the book was published?

Mr Linker: The theocons are a group of (mostly) Catholic intellectuals who have sought to provide the (mostly) evangelical Protestant religious right with a governing ideology derived largely from the papal encyclicals of Pope John Paul II. They believe the United States is in its essence a Christian nation founded on principles of Catholic natural law. In their view, the sexual revolution (and especially the Roe v Wade decision of 1973) broke from these Catholic principles and began an attempt on the part of secular liberals to institute a "culture of death" in the United States. To the extent that the Democratic Party is the political home base of this effort, it deserves to be considered America's "Party of Death", which is what National Review's Ramesh Ponnuru dubbed it in the subtitle of a recent book.

The leader of the theocons for much of the past three decades was Richard John Neuhaus, who died in January 2009. Since his death, Robert P. George of Princeton University has become the most vocal and influential member of the movement. (Mr George is the co-author, with Notre Dame's Gerard V. Bradley, of the Federal Marriage Amendment that would ban same-sex marriage at the level of the constitution.) The other leading theocons are George Weigel, Michael Novak, Hadley Arkes, and Maggie Gallagher. Supreme Court Justices Antonin Scalia and Clarence Thomas have expressed considerable theocon sympathies over the years. The greatest champions of their ideas in Congress in recent years have been former Senator Rick Santorum or Pennsylvania, Senator Sam Brownback of Kansas, and Senator Jim DeMint of South Carolina.

The political influence of the theocons reached a high point during George W. Bush's 2004 re-election campaign and in the early months of his second term. The Terry Schiavo right-to-die debacle of March 2005—in which prominent Republicans, including the president, conspired to pass a law specifically designed to overrule the Florida judges who had granted Schiavo's husband the right to remove her feeding tube—marked the pinnacle of theocon influence. Today the theocons are an important faction within the Republican Party, exercising a veto over any pro-choice candidate for president. (Just ask Rudy Giuliani.) Their future influence will depend on the electoral success of the GOP—and on the cluster of issues that propel it into power. Among likely Republican candidates for president, Indiana Governor Mitch Daniels, who has spoken of wanting to see a truce in the culture wars and who seems primarily motivated by a desire to trim the federal budget, would seem to have little interest in promoting a theocon agenda. Mitt Romney, Mike Huckabee and Sarah Palin, on the other hand, appear eager to champion theocon ideas.

DiA: A few weeks ago I was at the Values Voters Summit, where social conservatives appeared worried that economic conservatives were drowning out their message in the run up to the mid-term elections. What role, if any, do you think religious concerns are playing in the backlash against Barack Obama and the Democrats?

Mr Linker: With unemployment stuck well above 9%, economic issues are bound to trump other concerns, including the issues near and dear to social conservatives. So their anxiety is well founded. At the same time, though, their cultural outlook has indeed played an important role in fueling the backlash against Barack Obama and the Democrats. The religious right believes that America is a Christian nation—and its Christianity is narrowly defined: staunchly conservative, evangelical in style (even when it has been influenced by Catholic intellectuals), and overwhelmingly white. Put all of this together and you get the assumptions that define social conservatism as well as much of the right's opposition to the president and his party: To be a good American (or even an American at all), you have to be a Christian; and to be a Christian, you need to be a white, evangelical conservative. Since the president is not white and not an evangelical conservative, it follows that he must not be a “real” Christian—and that he may even be a closet Muslim. And since he isn't a “real” Christian, it follows that he must not be a patriotic American. Perhaps he even hates America and wants to see it brought low for its myriad historical crimes. (This is the paranoid conspiracy theorising to which Forbes magazine recently gave legitimacy in its disgraceful cover story by Dinesh D'Souza.)

So social conservatives do contribute in all kinds of important ways toward setting the tone of right-wing opposition to Mr Obama and the Democrats. This was perhaps clearest in Glenn Beck's Washington rally at the end of August. Most commentators remarked on how apolitical the event was, but I disagree. While it's true that Mr Beck didn't attack the president and the Democrats by name, the main point of his lengthy remarks was to portray the country in apocalyptic terms and then to set up himself, his followers, and their Christian piety as the only things that can save the nation from seemingly certain destruction. The choice was clear: Allow the people currently running the government (namely, the Democrats) to continue destroying the country—or put people like “us” (conservative Christians, genuine patriots) in charge to save the day, just like the “Black Robe Regiment” of Protestant clergy who rallied the American colonists to throw off the yoke of the godless British tyranny during the American Revolution. That sounds pretty political—and pretty radical—to me.

DiA: In your new book you say that all politicians should have to take a religious test. That's interesting, because it seems like national candidates already face an unofficial religious test. As David Brooks has written of Americans, “Their President doesn't have to be a saint, but he does have to be a pilgrim. He does have to be engaged, as they are, in a personal voyage toward God.” How would your test be different?

Mr Linker: I take David Brooks to be saying that Americans expect their politicians to be vaguely religious. I agree, but in my book I'm talking about something very different. In recent years an influential minority of Americans—the minority that makes up the religious right—has convinced (usually Republican) candidates for high office that traditionalist religious faith belongs at the core of their identities and at the centre of their political campaigns. I think this is quite wrong. Liberal-democratic politics is a good thing, and so (in many cases) is piety—but not all good things go together.

History shows us that traditionalist religion can be compatible with various forms of non-liberal government (theocracy, absolute monarchy). The same can be said for strident atheism and totalitarianism. Conversely, when religion is liberal—when it makes few supernatural claims, when it is doctrinally minimal, and when it serves mainly as a repository of moral wisdom—it can play a significant role in a liberal society. But the relationship between traditionalist religion and liberal politics is far more contentious—especially as we approach the most intense forms of piety and the most exalted forms of citizenship (which involve serving in high political office). A deeply devout Christian—someone who places his faith at the centre of his life—will tend to think of himself first and foremost as a member of the one true church working toward the establishment of the kingdom of God under Jesus Christ, if not in this life, then in the next. His ultimate loyalty will be to Christ, just as the ultimate loyalty of the most observant Jew will be to God and the Torah, while a Muslim's will be to Allah and the Koran. Liberal citizenship at its peak, by contrast, requires devotion to the liberal institutions and democratically-enacted laws of the political community above all else. That's why American presidents and other high officials swear an oath to uphold the Constitution and not natural or divine law of any kind.

These divergent loyalties may not come into direct conflict every day, but they nonetheless stand in deep and abiding tension with one another, forever threatening to pit the theological duties of the devout believer against the political duties of the citizen. It is possible for someone of liberal or moderate belief to be a great president—because his faith will make few potentially uncompromising, illiberal demands on him. The same cannot be said of the most devout believers. The religious test proposed in my book—which raises pointed questions about the doctrines and dogmas of specific religious traditions and could easily be administered in a special presidential debate devoted to faith and morals—would push candidates to acknowledge the need to draw distinctions between their piety and the nation's politics. The goal of the test is to get candidates to admit that the theological-political synthesis advocated by the religious right is neither possible nor desirable. As long as the United States remains a liberal nation devoted to individual freedom, traditionalist religion at its peak will fail to harmonise with politics at its peak. Our saints will not be statesmen and our statesmen will not be saints.

If David Brooks were right in saying that Americans don't long for their leaders to be saints, my book and its distinctive test would be unnecessary. But alas...

DiA: I feel like atheists would have an easy time passing your test. Do you think some atheistic beliefs—if that's not an oxymoron—are incompatible with liberal democracy?

Mr Linker: Yes, I do. Unlike many Americans, I would have no problem with a non-believer serving in high office. (I see no evidence that moral or political wisdom requires belief in a deity.) Yet I also think that the so-called new atheists present a special case, which is why I devote one of the six chapters in my book to criticising such writers as Sam Harris and Richard Dawkins. Mr Harris has denounced religious toleration, one of the founding ideals of liberal politics. Mr Dawkins, meanwhile, calls religious education a form of child abuse, which seems to imply that devout parents should be thrown in jail and their children placed in protective custody by the state. Such views are profoundly illiberal and have far more in common with the intolerant, ideological atheism of the French Revolutionary Terror and Marxist dialectical materialism than the humanistic scepticism of Socrates, Voltaire, or Camus.

The members of the second, more humanistic tradition of atheism understood and accepted that although an individual may settle the question of God to his personal satisfaction, it is highly unlikely that all human beings will settle it in the same way. They recognised that differences in life experience, psychological makeup, social class, intelligence, the capacity for introspection, and temperament will tend to preclude unanimity about the fundamental mysteries of human existence, including God. Humanistic atheists accept this situation; ideological atheists, including our bestselling new atheists, do not.

I fear that far from shoring up the secular political tradition, the arguments of the new atheists are likely to produce a country poised precariously between opposite and mutually antagonistic forms of illiberalism—as well as one in which traditionalist believers feel vindicated in their suspicion that a liberal society is fundamentally hostile to their convictions. The last thing America needs is a war of attrition between two mutually exclusive, absolute systems of belief. In place of absolute faithlessness, we need intelligent faith and open-minded doubt.

DiA: What do you make of the claim that the country's founders set out to create a Christian nation?

Mr Linker: It depends on what's meant by the claim. If it means that the founders assumed the United States would remain overwhelmingly Christian in a demographic sense, they are quite right—and that assumption has been vindicated. Our Christianity is more Catholic than the founders would have predicted or (in many cases) approved of, and non-Christians (including atheists, Jews, Muslims and other groups) play a significant role in the nation's political culture. But well over two centuries after the country's founding, the United States is a nation still very much dominated by Christianity.

But this is not really what most people mean when they say the founders set out to create a Christian nation. They mean, instead, that in its principles and aspirations—that is, in its national essence—the United States must be understood as an outgrowth and expression of Christian civilisation. On one level, this is trivially true. Two thousand years after Christianity began to spread throughout the Roman Empire, ultimately converting nearly every living soul in the Western world, isn't just about everything in the West in some way an outgrowth and expression of Christian civilisation, from democracy and capitalism to individualism and human rights?

But on the level that the Christian nationalists intend it, the claim is flatly untrue. The Declaration of Independence is, at most, a deist document. And the constitution famously makes no reference whatsoever to a deity of any kind. It is a metaphysically neutral document, taking no position for or against God—or for or against any particular views about God and what he might want or not want from human beings—beyond assuring that individual citizens have the right to believe just about anything about their ultimate ends, provided that they give up the ambition to political rule in the name of those beliefs. If that makes America a Christian nation, then the phrase is meaningless.