Any authors would be pleased by an array of laudatory and thoughtful comments on their work, especially by a group of critics as distinguished and diverse as this. We are grateful for the care and attention our commentators have taken with American Grace, especially given that they are outside of our own discipline of political science. In writing this book, our hope was to speak beyond disciplinary boundaries. It is thus particularly gratifying to read John Torpey describe American Grace as “public sociology.” This is precisely what we hoped to achieve. We believe that more social science should be directed toward informing our public discourse, and that rigor versus relevance is a false choice.

But writing for an audience that includes non-specialists and specialists alike—and specialists from many different fields at that—risks raising expectations for what we will cover. Jon Butler, for example, takes us to task for not including enough history; Molly Worthen suggests that we need more theology. Similarly, other reviewers have called for more constitutional law, political philosophy, and organizational sociology. Not to mention the members of many different religious groups who have written to ask why their group—the Quakers, say, or the Eastern Orthodox—are not featured more prominently. We readily concede that American Grace does not cover all of these subjects in depth. Perhaps, however, other authors will build on the themes, arguments, and data of American Grace to examine these other subjects in greater detail. And one of us (Campbell) is currently engaged in another project to go deep in examining one such topic discussed at length by Jon Butler—Mormonism.

David Hollinger, in contrast, does not call for anything, but instead hints at a lament for the state of religion as we describe it. We have been struck by his comment that the form of religion we describe is “bland” or, more pointedly, that blurred religious boundaries mean that Americans do not take their religion very seriously. Other critics, too, have commented on the tolerant religiosity described in American Grace, but unlike Hollinger, argued that such a religion is hardly worthy of the name. Wilfred McClay, writing in the Wall Street Journal, noted that “Surely there is something ironic about preferring a form of religion that asks us to admire and study the great prophets and preachers while warning us against imitating them and their true-believing faith.” Like Hollinger, theologian Charles Mathewes accepts our empirical description of American religion, but unlike Hollinger, he rejects the idea that “bland is beautiful.” In a panel discussion at the 2011 American Academy of Religion annual meeting Mathewes argued that “American Grace is very bad news for American religion and civic life, because churches seem unable to offer a thick counter-narrative to contemporary society.”

If Americans do not take their religion all that seriously, or fail to insist on its superiority to other religions, does this mean that religion has lost its ability to inspire change—either for individuals or society as a whole? Of all the questions to arise in the commentary surrounding American Grace, this is perhaps the most interesting, important and, ultimately, impossible to answer. Have we reached the end of prophetic religion? Is ecumenism ineluctably unable to stir souls? Must a prophetic religion be intolerant of those who disagree? Our own history suggests not. The civil rights movement certainly involved a prophetic call for personal and social reform, yet united Americans of many different faiths. America would be a meaner place without the recurrent challenge to accepted ways that religiously-rooted social movements have posed throughout our history, but we’re unconvinced that prophetic religion is intrinsically incompatible with religious pluralism.

It would be churlish of us to offer point-by-point responses to such thoughtful and generous commentaries. But one point has come up in the discussion of American Grace, including the essays of both Worthen and Butler, that warrants a reply. Both raise a red flag over the following sentence in the book:

The First Amendment to the Constitution says that Congress shall pass no law to curtail the free exercise of religion, but these sparse words do not fully reflect the way in which religious diversity is encoded in America’s national DNA.

In a recent symposium on American Grace, another commentator suggested that there are historians waiting to attack us in a dark alley because of this line, and that we probably regret ever having written it.

To the contrary, we have no regrets—although we have both decided to avoid dark alleys, at least when we know there might be historians around. At the risk of straining a metaphor to the breaking point, our point is simply that just as humans have a genetic code that shapes, but does not determine, their growth and development, so too was America set on a path that eventually led to our current state of—relative—religious harmony. For the Founders, religious diversity might have meant Presbyterians and Episcopalians, but the constitutional architecture they designed has enabled the conditions for harmony among a much wider array of religions. While constitutional guarantees are undoubtedly a necessary cause of religious tolerance, they probably are not sufficient. This is not a story of nature only; nurture mattered too. The constitutional prohibitions on the establishment of religion and wide protection for the free exercise of religion have interacted with other features of American society—immigration, civil society, public schools, the Cold War—to bring us to the point where, to borrow again from the language of genetics, the latent potential for religious tolerance has been “expressed.” None of this is to ignore the deadly manifestations of bigotry directed toward specific religious groups in America’s past, nor the current (albeit muted) antagonism toward Muslims, Mormons, and atheists. Just as our genes do not determine our destiny, these examples remind us that America’s DNA does not guarantee religious tolerance.

In his essay Torpey reminds us of the tensions arising from Islam’s presence in America, obviously a flashpoint of controversy for the current state of inter-religious relations. We say only a little about the public’s attitudes toward Muslims in American Grace but are now able to say more. Since the publication of our book we have collected another round of data, by returning to the same people we interviewed in 2006 and 2007. (Results from our latest round are soon to be published as an epilogue in the forthcoming paperback edition of American Grace). In this latest survey we dug deeper into Americans’ feelings about Muslims, by asking our respondents if they would approve of a mosque being built in their neighborhood. For comparison, we also asked how they would feel about a Christian church or Buddhist temple. The results are a classic case of interpretation hinging on perception. On the one hand, one could say that Muslims are welcomed. Nearly two-thirds of Americans say that they would be fine with a mosque in their neighborhood. Yet on the other hand, Muslims are less welcome than Christians or Buddhists. More Americans object to a mosque (35 percent) than a church (8 percent) or Buddhist temple (25 percent).

While it presumably comes as no surprise that a mosque evokes a more negative reaction than other houses of worship, those who—like us—care about the state of inter-religious relations should still be concerned about the negativity toward Muslims. We are even more concerned, however, about the partisan flavor of anti-Muslim feeling. When we employ an arsenal of demographic, social, religious, and political characteristics to predict unease with a mosque, we find that politics matters most. One’s level of religious commitment matters not at all, while there are only slight differences across religious traditions, with evangelicals slightly more opposed to a mosque than anyone else. It is partisanship—whether someone identifies as a Republican or Democrat—that has the biggest impact on attitudes regarding a mosque and thus, by implication, toward Muslims. When holding everything else constant, 56 percent of strong Republicans are bothered by a mosque, compared to 24 percent of strong Democrats. That is a huge gap.

The overlap between partisanship and anti-Muslim sentiment is a potentially explosive combination, especially if opposition to Islam were to become a regular feature of conservative political rhetoric. While, today, such sentiments are only on the fringes of acceptable discourse, more incendiary anti-Islamism might very well inhibit the inter-religious bridging in personal relationships that, for other religious groups, has led to their place in the religious mainstream (cf. Catholics, Jews). Non-Muslims might be reluctant to befriend Muslims, while Muslims might be socially marginalized and thus radicalized.

In other words, there is nothing inevitable about religious tolerance, in spite of the nation’s metaphorical DNA. Mormons are an especially timely example. They are one of the most religiously insular groups in America and, accordingly, face opprobrium in some circles (cf. Mitt Romney).

Our newest data also reveals a second major finding—“creeping secularism”—which also raises questions about the future trajectory of religious tolerance in America. In American Grace we detail the growth in the Nones, the religiously unaffiliated, who are concentrated among younger Americans. Now, with our latest data, we see evidence that the rise in Nonery is only the tip of the proverbial iceberg. What we term “the second aftershock” has, in fact, measurably strengthened since the first of our Faith Matters surveys in 2006. Secularism is surging among the Millennial generation. The youngest Americans—18 to 25—are far more secular than even those age 26 to 30. Not only are they the most likely to disclaim a religious affiliation, they are less likely to attend religious services, believe in God, believe in hell, and say that religion is not important in their lives. Young people are drifting, maybe even running, away from religion. And the public has noticed the slow and steady creep of secularism; just in the last five years, more and more Americans report a diminished role for religion in American society.

We also find further evidence for a key claim in American Grace, namely that America’s receding religiosity, especially among the young, is largely due to an allergic reaction to the mixture of religion and conservative politics. As a result, the religious-secular divide has a partisan flavor, suggesting a parallel with the partisan nature of anti-Muslim sentiment.

There is, however, a big difference between attitudes toward Muslims and the non-religious. While only a small percentage of non-Muslim Americans are personally acquainted with a Muslim, a growing percentage of religious Americans know someone who is “not religious”—rising from 44 percent of Americans in 2006 to 51 percent in 2011. Just as homosexuals coming out of the closet and revealing their sexual orientation to family and friends is one cause of the increasing support for gay rights, so too as more secular and even atheist Americans express their views to close acquaintances, tolerance for secularism seeps through the broader population. This degree of bridging seemingly bodes well for the health of relations between religious and secular Americans.

On the other hand, the label of “atheist” remains anathema to most Americans. While younger Americans are more favorable toward atheists than their elders, on average they still view them negatively. Like attitudes toward Muslims, the negative perception of atheists can be explained by the simple fact that very few Americans know a self-described atheist. There just are not that many atheists to go around, although the creeping secularism in American society suggests that their ranks are growing.

Just as growing acceptance of Muslims is not a given, neither should we assume the inevitability of full inclusion for non-religious Americans, whether atheists or not. Mutual tolerance would suffer if heated rhetoric about the “other side” were to separate Americans into religious and secular bunkers. In American Grace, the basic story is that while our politics may be polarized along religious lines, our personal relationships are not. If polarization at the personal level were to replicate the polarization of our politics, hostility would replace acceptance.

How likely is it that America fractures along religious lines? Notwithstanding the alternative scenarios we have described, we are optimistic enough to think that, in time, Mormons, Muslims, and atheists will be fully accepted into the mainstream of American society. But likely is not the same as inevitable.

Which brings us back to public sociology. While our primary objective has been description and explanation of the state of religion in today’s America, we are also willing to offer a prescription. It is our hope that Americans continue to forge interlocking personal relationships across religious—and non-religious—lines. If American Grace nudges its readers toward building more such bridges, so much the better. A house divided cannot stand, no matter our national DNA.