Churches are meddling in politics. Ministers are leading social movements, backing and attacking candidates, campaigning from the pulpit.

That was the complaint in the 1950s and ’60s, when clergy pushed for civil rights legislation, nuclear disarmament, and withdrawal from Vietnam. Some religious leaders attacked GOP presidential candidate Barry Goldwater for being too close to racists. In 1964 conservative journalist David Lawrence pushed back: “To preach a sermon . . . calculated to have an effect on the current Presidential campaign . . . raises a question of propriety if the principle of separation of church and state is to be maintained.”

Today, however, religion is associated strongly with the right. The transformation is evident not only in headlines, but also in white Americans’ behavior.

Back in the 1970s, the percentage of white liberals who disclaimed any affiliation with organized religion was only about ten points greater than that of white conservatives (14 versus 5 percent). But in the 2000s, the gap more than doubled, and it’s still growing. Between 1972 and 1984, 34 percent of whites who voted for Democratic presidential candidates—McGovern, Carter, Mondale—reported rarely attending church, only six points more than those who voted for the Republican candidates. In the 2000s, 49 percent of white Gore-Kerry-Obama voters were church avoiders, nineteen points more than the white Bush-McCain voters. Put another way, nearly all of the white Americans who drifted away from organized religion in the last few decades were liberals.

The latest election reinforced the trend. Obama lost weekly church attendees (of all races) by 20 points, while winning those who never attended by 28 points. The weekly attendees outnumbered the never-attendees two and a half to one. Similarly, Obama lost white evangelicals by 57 points and won the unaffiliated by 44 points, but white evangelical voters had twice the numbers of the unaffiliated of all races.

What happened between LBJ and BHO?

Starting in the 1970s, Republicans and white fundamentalist leaders moved toward each other. The Republican Party turned away from the liberal, high-church flavor of Wall Street Republicans such as John Lindsay and Henry Cabot Lodge Jr. Episcopal, Congregational, and Lutheran ministers were the sort who joined the King marches, anyway. Nixon’s winning strategy entailed (besides voicing southern whites’ racial resentments) courting the “silent majority” of working-class Americans who disproportionately belonged to conservative congregations, in part by standing up for “traditional” values against the ’60s long-haired, bra-burning counterculture.

At the same time, leaders of conservative denominations and independent churches responded to the era’s cultural threats—remember, Roe v. Wade was decided in 1973—by forgoing their earlier avoidance of politics. Rev. Jerry Falwell’s Moral Majority led the charge against abortion, sexual license, feminism, and the like, partnering with the new GOP. Devout white evangelicals had once voted Democratic, but by the 1980s they had switched sides. Republican-evangelical bonds continued to tighten, energized by the lasting abortion debate and emerging issues such as school prayer and homosexuality.

This is in some ways an odd alliance. Evangelical ministers praise the modern moneychangers and suggest that the rich will lead their camels through the eye of the needle and into the kingdom of God. But it is a powerful alliance.

White liberals reacted to the religious right by discovering the separation of church and state. More profoundly, many responded by separating themselves from churches. Since around 1990, Americans have increasingly announced to pollsters that they are religiously unaffiliated and never attend church. Much of this shift is politically driven. In effect, white liberals are declaring, “If religion means right-wing, anti-abortion, homophobic politics, then count me out.” Note that these people do not usually change their beliefs (or non-beliefs, as the case may be); they just declare their non-affiliation.

The left is not alone in shifting its religious sentiments to match the politics of the day. The rise of the religious right was itself in large part a reaction to the cultural agenda of the left in the 1960s and ’70s—loosening constraints on premarital sex, contraception, and abortion; undermining patriarchal authority; ridiculing bourgeois virtues; and celebrating cultural relativism—in short, sex, drugs, and rock ‘n’ roll.

Liberals continue to stoke believers’ resentments with litmus-test politics, such as hesitation over Pennsylvania’s anti-abortion Democratic Senator Bob Casey Jr.; banning crèches on public land at Christmas; comments such as Obama’s about rural voters who “cling to guns or religion”; and embracing the contemptuous “new atheists” and Jon Stewart–style ridiculing of faith.

The alienation of religion from the left is a problem for both sides. For the churches, it means losing young parishioners. Some leaders sense this loss. In the wake of the 2012 election, one stunned Southern Baptist leader said, “the entire moral landscape has changed. . . . An increasingly secularized America understands our positions, and has rejected them.” And the head of Focus on the Family confessed, “If the Christian message has been too wrapped around the axle of the Republican Party, then a) that’s our fault, and b) we’ve got to rethink that.”

The left should not be celebrating, however. Their separation from the churches means continuing estrangement from middle America. Part of the mythology of the left, rooted in the European experience, is that history is burying religion. Hardly; strong and widespread religiosity will be here in America for a long time.

These days, about 80 percent of white Americans say that they believe the Bible is either the word of God or was inspired by God and also that they believe in life after death. About 60 percent say that they know without a doubt that God exists and that they pray at least once a day. About 40 percent say that they attend church at least twice a month, and more than 30 percent say that they have had a “born again” experience in which they committed themselves to Christ. These percentages have not moved up or down by more than a few points in 30 or 40 years. (Black and Latino Americans are even more religious.)

Moreover, many of the one in six whites who say that they have no religion nonetheless endorse religious beliefs. For example, about 40 percent of the unaffiliated in the 2000s said that the Bible was dictated or inspired by God, and more than half said that they believed in life after death.

Scholars of religion debate the nuances in these numbers—how “true” these declarations of faith are, how much to make of modest declines in church attendance, what calling oneself “religious but not spiritual” means, and the like. Still, Americans overwhelmingly are, and for the foreseeable future will be, people who see themselves as believers.

Democrats probably cannot again attract most highly religious whites as they once did; that would entail regaining the South. But even a modest return—say, regaining one-fifth of the white evangelical vote—would have sizeable consequences.

A white evangelical left, descendants of MLK’s fellow marchers, remains. Historian David R. Swartz writes:

The marriage of [political] conservatism and evangelicalism was not inevitable. Nor is it inevitable that current alignments will persist. . . . To this day, political moderates and leftists—as represented by Sojourners, Evangelicals for Social Action, and the Association for Public Justice—comprise more than a third of American evangelicals.

Can the cosmopolitan left afford to turn them away by disparaging religion?

For the nation as a whole, the estrangement of the left from the religious raises the specter of a society—like many in Europe since the anti-clerical democratic revolutions of the nineteenth century and like many in the developing world today—that is polarized between politically conservative forces allied with religious institutions and progressive forces attacking religion for that very reason. Think of countries where a headscarf or a beard signals a political allegiance precisely because it signals religiosity. In the American context, at least, where so many are so religious, this prospect should be discouraging to all, but especially to the left.

Editors’ Note: This article appeared in the January/February 2013 print issue.