In 2012, No Religious Center Is Holding IN American religious history, Nov. 8, 1960, is generally regarded as the date when the presidency ceased to be the exclusive property of Protestants. But for decades afterward, the election of the Catholic John F. Kennedy looked more like a temporary aberration. Post-J.F.K., many of America's established churches went into an unexpected decline, struggling to make their message resonate in a more diverse, affluent and sexually permissive America. The country as a whole became more religiously fluid, with more church-switching, more start-up sects, more do-it-yourself forms of faith. Yet a nation that was increasingly nondenominational and postdenominational kept electing Protestants from established denominations to the White House. The six presidents elected before Kennedy's famous breakthrough included two Baptists, an Episcopalian, a Congregationalist, a Presbyterian and a Quaker. The six presidents elected prior to Barack Obama's 2008 victory included two Baptists, two Episcopalians, a Methodist and a Presbyterian. Jimmy Carter's and George W. Bush's self-identification as "born again" added a touch of theological diversity to the mix, as did losing candidates like the Greek Orthodox Michael S. Dukakis. But over all, presidential religious affiliation has been a throwback to the Eisenhower era - or even the McKinley era. That is, until now. In 2012, we finally have a presidential field whose diversity mirrors the diversity of American Christianity as a whole. Barack Obama, Mitt Romney and Rick Santorum all identify as Christians, but their theological traditions and personal experiences of faith diverge more starkly than any group of presidential contenders in recent memory. These divergences reflect America as it actually is: We're neither traditionally Christian nor straightforwardly secular. Instead, we're a nation of heretics in which most people still associate themselves with Christianity but revise its doctrines as they see fit, and nobody can agree on even the most basic definitions of what Christian faith should mean. This diversity is not necessarily a strength. The old Christian establishment - which by the 1950s encompassed Kennedy's Roman Catholic Church as well as the major Protestant denominations - could be exclusivist, snobbish and intolerant. But the existence of a Christian center also helped bind a vast and teeming nation together. It was the hierarchy, discipline and institutional continuity of mainline Protestantism and later Catholicism that built hospitals and schools, orphanages and universities, and assimilated generations of immigrants. At the same time, the kind of "mere Christianity" (in C. S. Lewis's phrase) that the major denominations shared frequently provided a kind of invisible mortar for our culture and a framework for our great debates. Today, that religious common ground has all but disappeared. And the inescapability of religious polarization - whether it pits evangelicals against Mormons, the White House against the Catholic Church, or Rick Santorum against the secular press - during an election year that was expected to be all about the economy is a sign of what happens to a deeply religious country when its theological center cannot hold. Our president embodies this uncentered spiritual landscape in three ways. First, like a growing share of Americans (44 percent), President Obama changed his religion as an adult, joining Chicago's Trinity United Church of Christ in his 20s after a conversion experience brought him out of agnosticism into faith. Second, he was converted by a pastor, the Rev. Jeremiah Wright, whose highly politicized theology was self-consciously at odds with much of historic Christian practice and belief. Finally, since breaking with that pastor, Obama has become a believer without a denomination or a church, which makes him part of one of the country's fastest-growing religious groups - what the Barna Group calls the "unchurched Christian" bloc, consisting of Americans who accept some tenets of Christian faith without participating in any specific religious community. Obama's likely general election rival, Mitt Romney, has had a less eventful religious journey, remaining a loyal practitioner of his childhood faith. But that faith, the Church of Jesus Christ of Latter-day Saints, is the ultimate outsider church, persecuted at its inception and regarded with suspicion even now. Christian theologians wrangle over whether Mormon beliefs should be described as Christianity; Mormons, for their part, implicitly return the favor, since they believe that true Christian faith was restored to earth by Joseph Smith after nearly two millenniums of apostasy. Indeed, between its belief in a special 19th-century revelation and other doctrinal embellishments, Mormonism is arguably as far as Jeremiah Wright's black liberation from what used to be the American religious center. Ross Douthat is an Op-Ed columnist for The New York Times. This article is adapted and excerpted from his new book, "Bad Religion: How We Became a Nation of Heretics."