Back in the 1990s, when the Religious Right was ascendant, the so-called secularization thesis was widely dismissed as a myth arising from the intellectual prejudices of educated elites. “From the beginning,” writes sociologist Rodney Stark, “social scientists have celebrated the secularization thesis despite the fact that it was never consistent with empirical reality.” Secularization, according to Stark, was essentially a European phenomenon. In the United States, respect for religious freedom forced “religious firms” to respond to the demands of believers in an unregulated “religious economy,” which generated high religious participation and made America vibrantly religious. Twenty-five years later, however, the secularization thesis has struck back. Although the United States remains a highly religious country compared to the rest of the world, numerous trends suggest, in the words of sociologist Mark Chaves, that despite “substantial continuity in American religion there are clear signs of decline.” The causes of decline are hard to identify, and the future of religion hard to predict. But that the United States is undergoing some degree of secularization is hard to deny, a reality that portends changes for the role of religion in American public life.

One striking feature about religious commitment today is how closely it aligns with conservative politics. Religiously committed Americans—except Black Protestants—are very likely to vote Republican. Yet it wasn’t always that way, a point argued in great detail by Robert Putnam and David Campbell in their well-received book American Grace. According to these authors, the current alignment between religion and conservative politics traces back to the cultural upheaval of the 1960s. Putnam and Campbell describe a “shock and aftershock.” The 1960s launched a cultural revolution that challenged traditional norms and values; the late 1970s and 1980s produced a conservative reaction that flourished in the Reagan years, and the United States lurched into what many have called the “culture wars.”

For those who were religiously committed, the most important battlefield in the culture wars involved sexual morality, where public attitudes shifted dramatically. Between 1969 and 1973, the number of Americans who said premarital sex was not “wrong” jumped from 24 percent to 47 percent, and 62 percent of Americans no longer disapproved of premarital sex by 1982. Greater acceptance of nonmarital sex was part of a larger package of changing attitudes toward contraception, divorce, single parenthood, and so on. These changes challenged traditional Christian understanding. Culturally conservative Christians constituted an important block within a large segment of American society that resisted the cultural changes wrought by the 1960s. Eventually, that resistance would be channeled by the Republican Party.

According to Putnam and Campbell, the current alignment of religious commitment with the GOP can be explained almost entirely by two issues; abortion and same-sex marriage. Although much about the Sixties sexual revolution bothered culturally conservative Christians, only abortion and same-sex marriage played a key role in reconfiguring politics. The Republican and Democratic Parties took unequivocal and opposing positions on abortion for the first time in 1980. About then the Republican Party also began associating itself with opposition to same-sex marriage. This new political alignment presented religious voters with a clear choice. The Republican Party aligned perfectly with the issues most important to them, and they migrated to the Republican Party.

At the same time—so argue Putnam and Campbell—Christian alignment with Republican politics generated a counter-reaction in the 1990s and early 2000s, which in turn is contributing to the rise of so-called “nones”; that is, Americans with no religious affiliation at all. In 1957 only 3 percent of Americans said they had no religious affiliation; in 2014 that number was 21 percent; in 2019 the number was 26 percent. Today there are more nones in the United States than Roman Catholics, and approximately the same number of nones as evangelicals. The explanation for this accelerated and dramatic rise in nones is no doubt complex, but part of the explanation appears to be widespread distaste with politically motivated Christianity. Surveys from the early 1990s on show increasing numbers of Americans objecting to the influence of religion on politics. The nones, who are represented disproportionately by people to the center or left of the political spectrum, are perhaps especially turned off. Because people associate religion with conservative politics so closely, those who aren’t conservative turn away from religion. As Mark Chaves explains, “After 1990 more people thought that saying you were religious was tantamount to saying you were a conservative Republican. So people who are not particularly religious and who are not conservative Republicans now are more likely to say that they have no religion.” The growth of the nones is thus working to reinforce the conservative-religious and liberal-secular alignment of contemporary American politics.

That alignment is stunning when viewed against the backdrop of American history. Religion in America has always exerted influence, but that influence grew out of its broad purchase in American culture. The famous Frenchman Alexis de Tocqueville, who visited the United States in the 1830s, was surprised by the important role religion played in American democracy. Famously, he attributed the strength of American religion to its distance from politics. In America, Tocqueville notes, the clergy “separate themselves carefully from all parties, and avoid contact with them with all the ardor of personal interest.” Because religion in America distanced itself from politics, it had less power but greater influence. Religion in Europe, by contrast, allied itself with political power but was weak and diminished. The reason, Tocqueville explains, was that religion allied with power was inevitably tainted by factional political interests:

As long as a religion is supported only by sentiments that are the consolation of all miseries, it can attract the hearts of the human race to it. Mixed with the bitter passions of this world, it is sometimes constrained to defend allies given it by interest rather than love; and it must repel as adversaries men who often still love it, while they are combating those with whom it has united. Religion, therefore, cannot share the material force of those who govern without being burdened with a part of the hatreds to which they give rise.

This admonishment against allying religion with politics, which Tocqueville wrote for Europeans, reads today like a lesson for Americans. One of the most striking features of the current American political configuration, in which religious and conservative voters are tightly aligned, is how far it deviates from America’s traditions and how much it resembles Europe.

The “europeanization” of American politics, far from a reason to rejoice, should be the occasion for wailing and gnashing of teeth. Europe’s churches, confronted with the changes of modernity, considered catering to power the best defense against waning influence. Easy prey for reactionary politics, Europe’s churches frequently found themselves allied with the losers of history. Secularization, originally concerned with reducing ecclesiastical privileges, became synonymous with progress itself. Today Europe is most likely the most secular place on earth.

The history of Christianity in the modern period suggests that political alliances bring short-term gains and long-term loss. The Religious Right in America ascended rapidly in the 1990s but subsequently suffered defeat in every battle of the culture war, with the one notable exception of abortion. In the meantime, Christian influence on American culture has waned. A better long-term strategy might heed the advice of Alexis de Tocqueville and return to the politically detached Christianity of America’s founding.

The possibility of detachment is not as far-fetched as it may seem. Insofar as the contemporary religious-conservative alignment in American politics has been driven by the issues of same-sex marriage and abortion, a shift in the salience of those issues could lead to disengagement. The political debate over same-sex marriage in the United States is effectively over. Public attitudes on the question have shifted dramatically, and unlike with Roe v. Wade, the Republican Party has not made overturning Obergefell a vital part of its political platform. Even if religiously committed voters remain opposed to same-sex marriage, neither political party aligns with their preference on this issue. Abortion, admittedly, is a different matter. It remains important to religious voters and to GOP. Even so, one cannot exclude the possibility that abortion might lose its power to configure politics single-handedly. The abortion rate in the United States has declined significantly in recent decades. Easy access to effective contraception, including the so-called morning-after pill, makes recourse to abortion harder to justify, and surveys suggest attitudes toward abortion have grown more restrictive among millennials. Meanwhile, conservative appointments to the Supreme Court have made the issue of abortion less constitutionally urgent for those who oppose it. One can therefore imagine a kind of a societal truce emerging on the issue. Religious voters will continue to oppose abortion, but for younger voters not directly shaped by the cultural upheaval of the Sixties and Seventies, the issue of abortion may prove less neuralgic, such that they are willing to weigh it against other political preferences.

Even if the alignment between religious voters and the Republican Party should begin to loosen, however, that alone would hardly arrest the course of secularization. It would, however, be a first step. If America’s churches would seek to avoid a European fate, they might turn their gaze back to what was unique about their history. Unlike in Europe, American Christianity was once confident in itself and comfortable in the modern world. Shaped largely by a Protestant piety concerned with spiritual renewal and personal holiness, America’s churches spoke to people of every political creed. “Truth is lost not by teaching but by disputing,” writes the early Pietist Jacob Spener, “for disputations bring with them this evil, that men’s souls are, as it were, profaned, and when they are occupied with quarrels they neglect what is most important.”