How can a religiously diverse and devout country such as the United States avoid religious tension? According to the final chapter of American Grace by Robert D. Putnam and David E. Campbell, the answer lies in the growing interpersonal links that connect Americans of different faiths through marriage and friendship. These links “have kept America's religious melting pot from boiling over” (548). Before reaching this conclusion, the authors take the reader on a sweeping journey across a range of empirical evidence.

As a contribution to the burgeoning scholarship on religion in American society and politics, American Grace takes a fresh approach to its topic. First, it offers a clear narrative of the fluctuations of American religiosity across several decades and up to the very recent past, connecting these fluctuations with social and political developments. Second, although relying heavily on survey-based evidence, the narrative accommodates recent calls for a more penetrating look at what actually is going on inside American congregations. Quantitative findings are fleshed out and complemented by the use of observational case studies or “vignettes” from selected congregations (Chapters 2, 7, 10; fieldwork conducted by Shaylyn Romney Garrett). The book also suggests a number of hypotheses for further study. To cite just one example, the authors speculate that technological advances in pregnancy ultrasound scans have strengthened the anti-abortion position among the mass public (412). The presentation of the survey-based results will satisfy the general reader (graphs, maps, and the odd cross-tabulation) while avoiding generalizations. At the same time, the endnotes and the technical appendices should convince the more methodologically inclined.

The main portion of the analysis is based on the Faith Matters Survey, a panel survey designed and implemented by the authors. This telephone survey interviewed the same sample across two waves in 2006 (N = 3,108) and 2007 (N = 1,909, or a 62 percent re-interview response rate of the 2006 sample). The panel design helps the authors to address certain causality questions that cannot be explored with simple cross-sectional data. However, as the authors themselves point out (462), the short-time span between the two waves limits the amount of change that can be documented. The authors ably supplement their own data with survey data from other sources, old and new: the General Social Survey, Gallup polls, various Pew surveys, the Panel Study of American Religion and Ethnicity, the Youth-Parent Socialization Survey, the American National Election Studies, the Independent Sector Giving and Volunteering Surveys, the Social Capital Community Benchmark Survey, and some census data.

The opening chapters (3 and 4) use survey data to tell the story of religiosity in America since the mid-twentieth century. The religiosity boom of the 1950s (the communism threat and civil religion) is followed by a religiosity decline in the 1960s (the counter-culture, sexual liberalization, the Civil Rights Movement). The 1970s and 1980s witnessed a conservative religious reaction, exemplified by the rise of evangelicalism and based on the perceived threat of sexual liberalization. This eventually led to a second reaction in the 1990s and the 2000s, expressed in the rise of religious “nones” as a response to the prominent public presence of conservative Christians.

Chapters 5 and 6 review data on religious choice (switching and intermarriage) and innovation (e.g., the online church). Chapters 8 and 9 examine the passive adaptation of religion to the growing feminist consensus, class inequality, and ethnic diversity of the last half century. Chapter 11 discusses the alignment of religious and political camps on the basis of sexual morality issues and changing party positions on these issues in the 1980s. Chapter 12 presents data on the explicit and, mostly, implicit presence of politics inside the American congregation. Not surprisingly, Chapter 13 illustrates how religious Americans generally make better neighbors and citizens, although Chapter 14 identifies some darker undertones in American religion, expressed as negative feelings between different faiths and religious-secular tensions.

Although the book does constitute an impressive journey, one methodological limitation in American Grace is the relatively small sample size of the Faith Matters Survey (and of most available datasets). In order to produce groups adequately sized for statistical exploration, the analysis applies a standard but crude religious categorization scheme, which creates groups such as “Jewish” or “Evangelical Protestant” (24). As an illustration of the methodological limitation, “Jewish” is treated as equivalent to “Mormon,” although contemporary datasets reveal that, unlike the Church of Jesus Christ of Latter-day Saints, the “Jewish” category is very heterogeneous (Pew Forum on Religion & Public Life, U.S. Religious Landscape Survey, 2008, N = 35,556). To cite another example, those who attend non-denominational mega-churches are included in the generic “evangelical” category, following common practice in the field. The analysis then finds that “eighty-three percent of evangelicals … say that other religions can bring salvation” (535), an indication of interfaith understanding. But as one of the qualitative vignettes illustrates, the non-denominational mega-church segment is clearly less sectarian than traditional evangelical denominations (61). Therefore, its inclusion in the “evangelical” category may inflate figures like the one reported above and lead to overly optimistic conclusions. The definition of heterogeneous religious categories would also tend to suppress any political differences between traditions.

In a second, related problem that is particularly evident in the main analysis on religion and partisan politics (Chapter 11), American Grace tends to emphasize the “God gap,” a term that describes differences between the more religious and the less religious irrespective of faith tradition. While the operationalization of this gap is based on reliable measurement (18), the authors tend to downplay political differences that separate religious traditions. For instance, Chapter 11 only briefly touches upon a 2006 snapshot of partisan differences between and among religious traditions (371), and the graphs and figures in that chapter are reserved for illustrating the “God gap.” If anything, one of the key tables in the entire book (508) suggests that tensions between religious traditions are not absent in twenty-first century America, even when using heterogeneous religious groupings.

Despite such limitations (which are mainly resource-based), American Grace is essential reading for those interested in a nuanced, multi-method account of the recent past and present of religion in American society and politics.