When I was a college junior in the fall of 1988, a friend told me in a rather serious tone that she wanted to have a talk with me. My mind raced, wondering whether I had done something to upset her. As it turned out, she wanted to tell me that she finally had chosen a candidate to vote for in the 1988 presidential election: George H. W. Bush. She had been wrestling with this decision for weeks, but in the end, she concluded: “I just can't vote for someone who supports abortion.” Just two years earlier, my friend had converted from the Catholicism of her youth to evangelical Protestantism. Her (nominal) Catholic roots were not driving her pro-life commitment; instead, she said, her opposition to abortion was something she had come to embrace since her born-again experience. Something of great consequence had changed in her life, and this personal transformation affected her political outlook in myriad ways, both then and now. To this day, my friend remains a committed evangelical and an equally staunch Republican. For her, and for millions of Americans like her, the process of defining one's religious identity has had long-lasting political ramifications.

Why are religious identity and political identity so profoundly intertwined in the United States? What mechanisms weave these two components of personal identity together so tightly? And how is it that American politics manages to withstand the pressures of religio-political polarization as gracefully as it would seem?

In their monumental book American Grace, Robert Putnam and David Campbell utilize a wealth of quantitative and qualitative data to situate my friend's story in a broad social-scientific context. They begin by asserting that “something's changed” over the last half century in the relationship between religion and American politics, much as something changed in my friend's life during her early adulthood. Unlike their forebears, many Americans today get worked up about the public posting of the Ten Commandments. A half-century after the election of John F. Kennedy, Catholic presidential candidates scarcely can count on support from a majority of their fellow Catholics, as John Kerry learned firsthand in 2004. Successive generations of Americans appear to be growing more secular. Religion's political significance has been transformed from a matter of “tribal loyalty” (p. 2) into a complicated matter of individual self-definition. The political division that now separates people who attend worship services frequently from those who never darken the door of a church is best described as a chasm.

Indeed, something has changed—American citizens today are perhaps more polarized both religiously and politically than ever before—yet American society and its polity remain resilient and (at least marginally) civil. We do not observe, nor have we ever, the sort of outward strife between religious groups in the United States that has scarred the length and breadth of human history. The Troubles are for the Irish; religion-based genocide is for continental Europe, Asia, or Africa—but not the United States. This is so despite the fact that the United States remains an outlier among developed nations for its high level of religiosity. The core purpose of Putnam and Campbell's effort is to sort out why a relatively peaceful religious pluralism manages to persist—indeed, to thrive—in the United States, even in the face of religio-political polarization.

American Grace is sweeping and broad, providing an eagle's eye view of American religion and its political significance. Clearly, it was Putnam and Campbell's intent to present their work in a broadly accessible manner, which is not to say that they do not also offer a wealth of detail upon which other scholars may draw. In a sense, they are forestry experts leading a tour that serves to point out some of the religion and politics subfield's more significant trees. No single work can summarize all of the complexities of the relationship between religion and politics in the United States, and it is worth noting that Putnam and Campbell hardly are endeavoring to write the last word. In fact, they only deal directly with politics in certain portions of the book; American Grace is as relevant to sociology, especially the sociology of religion, as it is to political science.

Political science was slower than the other social sciences to embrace the study of religion,Footnote ¹ but several decades of research served to elucidate the relationship between religion and politics even before the publication of this book. In recent years, the American Political Science Association even convened an official Task Force on Religion and American Democracy that resulted in a rich, edited volume on the subject.Footnote ² Elsewhere, Paul Djupe and I identify five distinct theoretical approaches—psychological, social psychological, social movement, contextual, and cultural—that undergird empirical scholarship on religion and politics.Footnote ³ Thanks to the breadth provided by their narrative, Putnam and Campbell's work touches on each of these theoretical approaches in one way or another.

Psychological approaches to the study of religion and politics, led in particular by Ted Jelen,Footnote ⁴ “view the key attachment point between religious faith and political commitments as the individual's identification with religious reference groups.”Footnote ⁵ Of primary importance in this tradition of scholarship are psychological attachments with religious groups, individuals, and ideas. Relationships among individual religiosity, moral traditionalism, and political orientation are the core concerns of social psychological approaches to the study of religion and politics. This research program, led by James Guth, John Green, and their colleagues, analyzes the political significance of religion's “three Bs”—“belonging,” or religious affiliation; “believing,” or theological orthodoxy; and “behaving,” or nature and degree of participation in religious activities.Footnote ⁶

Putnam and Campbell speak clearly to the psychological and social psychological approaches to the study of religion and politics throughout American Grace. Reflecting Putnam's previous work on social capital,Footnote ⁷ they deploy rich case studies to demonstrate how everyday personal relationships give rise to politically meaningful communities (see especially Chapter 10). They also analyze the power of interreligious personal ties to reduce prejudice and act as a hedge against religiously motivated violence. Most Americans, say the authors, have an “Aunt Susan”—a “saintly” member of one's own family who happens to belong to a different faith tradition—or a “pal Al”—a person one meets because of a shared secular interest who turns out to have a different religious background than oneself (pp. 526–34). Putnam and Campbell use data from their sweeping Faith Matters Surveys to demonstrate that such Americans are demonstrably more tolerant of religious diversity. On the other hand, the 11% of Americans who say that “one religion is true and others are not”—“true believers,” in their parlance—“live in … religiously monochromatic social environments [and] are much less likely to have an Aunt Susan or pal Al to perturb their unquestioning faith” (p. 546). In essence, Putnam and Campbell show us that the “mere exposure effect”Footnote ⁸ operates in the context of religious pluralism.

Even more specifically, Putnam and Campbell present empirical findings that bolster the social psychological approach to religion and politics. In Chapter 13, they show with remarkable clarity how religious adherence increases volunteering, civic engagement, social trust, and respect for authority while decreasing tolerance of dissent. They also note that attitudinal uniformity in opposition to abortion and same-sex marriage has solidified moral traditionalism, keeping conservative people of faith solidly on the Republican side. And while the authors do not directly engage Marc Hetherington and Jonathan Weiler's compelling work on authoritarianism,Footnote ⁹ they do touch on the relationship between being “authority-minded” and embracing religio-political conservatism (pp. 488–9).

Although most scholarly work employing social movement approaches is done outside of political science, research in this tradition focuses attention on exogenous forces shaping the religion–politics relationship that other approaches overlook.Footnote ¹⁰ Instead of beginning with the question of how religious variables affect people's political orientations, research using social movement theory tends to emphasize ways in which broad religious forces can inspire political participation.

Social movement theory implicitly seems to underlie Putnam and Campbell's treatment of the legacy of the 1960s as an exogenous explanation for the political salience of religious identity in twenty-first century America. With conservatism up against a wall, the new Right began building on Richard Nixon's “Southern Strategy” to reshape political alliances after the cultural upheaval of the sixties. Intellectuals and political strategists on the right reasoned that people who resisted changing moral standards, gender roles, sexual norms, and so forth ought to be especially open to conservatism. The post-1960s surge in evangelical Protestant religious affiliation broadened the base of Americans who were ripe for mobilization by politicians trumpeting a return to “traditional family values.” Putnam and Campbell add to our understanding of how profoundly the Republican Party benefited from this strategy; first, evangelical Protestants were realigned from their historic Democratic roots and, later, the Republicans became capable of casting themselves broadly as the party of “religious America.” The so-called culture war that pits conservative and largely religious voices against their progressive and frequently secular counterparts has its roots in this religio-political earthquake—and accounts for the intractability of debates about family- and sexuality-related issues in American politics.Footnote ¹¹

Contextual approaches to religion and politics, spearheaded by Paul Djupe,Footnote ¹² draw directly upon research about the political salience of social contexts and social networks.Footnote ¹³ The primary assertion of this vein of scholarship is that the local congregation is the key religious locus of political socialization: “[C]ongregational life presents myriad opportunities and information that help structure the civic engagement and political opinions of church members; indeed, the political life of church members cannot properly be understood without a detailed explanation of how and why congregations exert such influence over their members.”Footnote ¹⁴

Putnam and Campbell discuss the political significance of congregations both individually (through qualitative vignettes) and in the aggregate. Their findings regarding congregational life highlight the substantive and theoretical significance of contextual approaches to the study of religion and politics. At first glance, the following observation might give contextual scholars pause: “In short, there is little politics in church” (p. 419). However, the authors make this observation to set up their contention that politics happens through (or perhaps as a result of), rather than in, church. And of course this is true: Clergy tread on eggshells whenever the subject of politics arises in a formal setting out of fear that their congregation might lose its tax-exempt status. Politics per se is not what compels most people to attend worship services or otherwise commit themselves to religious practice. Instead, as Djupe's work shows, the political ramifications of religious adherence are a by-product of regularly placing oneself in a social milieu where politically relevant messages are conveyed indirectly but regularly, often through casual conversation. In fact, Putnam and Campbell show that religiously based social networks foster civic engagement (pp. 473–8), which is convergent with Djupe's contention that such social networks can improve the quality of democratic deliberation.Footnote ¹⁵

For decades, David Leege and Kenneth Wald have championed cultural approaches to religion and politics.Footnote ¹⁶ In any culture, individuals pick and choose which values to espouse on the basis of their favored social characteristics or relationships. As American culture has been infused over the last several decades with even more individualism, anomie, and cynicism, it is no wonder that religious identification has become a higher priority for many Americans—and thus that it has a powerful effect on how they view politics.

I would like to have seen Putnam and Campbell use cultural theory more explicitly than they did, but insights that are consistent with the cultural approach abound in American Grace. For example, they note that the attitudinal “religious divide” (or the so-called God gap) between the most religious and most secular Americans is largest among young people (pp. 406–14), and that young people today are more likely than members of any generation before them to eschew organized religion (pp. 124–5). Moreover, as they note: “Something about American history over the last century led younger religious cohorts to adopt a ‘live and let live’ attitude” (p. 487). Indeed, something has changed. To the extent that American culture is malleable, it has been transformed in the last half century. Fewer and fewer parents are raising their children “in the church” because doing so is no longer as culturally prescribed as was the case in previous generations. On the other side of the coin, however, younger Americans who are religious appear especially drawn to evangelical Protestant contexts—in part because evangelical churches present their message in ways that resonate with today's popular culture.

For decades to come, scholars of religion and politics will continue to explore how and why religious identity and political identity are woven together in the United States. Like Putnam and Campbell, they will be guided by the fact that the culture war has remained relatively—and remarkably—bloodless. They will marvel at the extent to which Americans who find themselves on opposite sides of the culture war usually manage to coexist peacefully, even harmoniously—as has my college friend with her progressive friends and family members. Putnam and Campbell's paramount contribution is their remarkable facility in explaining—in terms any educated reader can understand—why Americans are able to manage their religious differences in the course of day-to-day life as well as they do. Barring unforeseen circumstances, peaceful pluralism amid religio-political polarization will likely continue in the decades to come, especially because the youngest generations of Americans are being raised in a more tolerant atmosphere than ever before. Social scientists across disciplines will be eager to study how they remake the relationship between religion and politics in twenty-first-century America.