Rock of Ages is the latest in Temple University Press’s Religious Engagement in Democratic Politics series, edited by Paul A. Djupe. In it, Jeremiah J. Castle investigates one of the most pivotal groups in modern US politics, white evangelicals. Many have characterized the seemingly unprecedented level of support from white evangelicals as essential to Trump’s 2016 victory. In a country where several major demographic trends favor the Democrats, the future of the Republican Party seems to be in the hands of a constituency that is already turning out at high rates and showing exceptional loyalty. How long can the Republican Party count on a strategy of increasing its support among white evangelicals in a country that will soon no longer be majority white? Rock of Ages peers into the political future by examining evangelical youth.

The backdrop for Castle’s study is punditry and scholarship highlighting liberal trends among young evangelicals, as well as speculation that these trends portend a political reversal. From the first page, he notes, “Writing for ABC News, Dan Harris (2008) claimed that young evangelicals were ‘breaking from their parents and focusing on a broader range of issues than just abortion and gay marriage’” (p. 1). However, Castle notes that such assertions rest on relatively superficial analyses of young evangelicals. Although public opinion differences across generations of evangelicals have been identified, the causes and political consequences of those differences have heretofore been undertheorized and largely unexamined.

Castle’s theory, “A Subcultural Theory of Public Opinion among Evangelicals” (the title of chap. 1), answers questions about whether young evangelicals are blazing a new political path and why. The theory is described thusly: “the evangelical subculture takes part in four processes that together give it the potential to exert a substantial influence on public opinion: building evangelical social group identity, promoting the distinctive beliefs of the subculture, discrediting certain aspects of mainstream culture, and delivering explicitly political messages” (p. 17).

Castle reviews the history of the evangelical movement, emphasizing events that contribute to evangelical distinctiveness via the four processes that he identifies. When it comes to post–Civil War history in the United States, he emphasizes distinctive cultural attitudes, such as opposition to teaching evolution and to legal abortion. Evangelical resistance to school integration receives much less attention.

Crucially, Castle goes on to emphasize that a subculture ensures its future by attending to the way youth are socialized. He also adds qualifications to more general subcultural theories by emphasizing that the evangelical subculture will have the greatest public opinion effects where the issues are core to the group’s identity and among those most immersed in the subculture. For these extensions of subcultural theories, Castle draws on John Zaller’s (1992) “Receive-Accept-Sample” model (The Nature and Origins of Mass Opinion, Cambridge University Press) and the idea that the sample of considerations that members of a subculture “draw” from when responding to survey questions will be most distinctive for the matters to which the subculture attends most and for those most committed to the religious community.

To test the subcultural theory, Castle assesses a wealth of public opinion data including the 2014 and 2007 Pew Religious Landscape Studies, the 2012 and 2016 Cooperative Congressional Election Studies, and the General Social Survey time-series data. He also conducted 42 semistructured qualitative interviews in 2013 with evangelical students at five colleges to bring a mixed-methods analysis to bear on the causal mechanisms.

For students of religion and politics, Rock of Ages will surely be a definitive reference for comparing public opinion and political behavior of evangelical and non-evangelicals across age groups. Name the issue, attitude, or behavior, and you will find documentation of the relevant comparisons in this book.

To summarize, Castle finds evidence of distinctiveness among young evangelicals, but primarily for issues he categorizes as “Noncultural Issues.” Thus he finds little evidence of daylight between younger and older evangelicals on abortion. The rift is more evident when it comes to attitudes about welfare and immigration. Attitudes about gay marriage are the most notable exception to this pattern (a cultural issue evincing an age-based rift). But according to Castle, “continued Republican identity and political conservatism of young evangelicals suggest that any issue changes do not seem to be affecting their overall political affiliations” (p. 68). Furthermore, when divided by level of commitment, Castle finds less change among high-commitment young evangelicals, again especially for key cultural issues. The subculture resists change on core issues, and resistance is most evident among those highly committed to the subculture.

If Jeremiah Castle’s crystal ball is correct, it is unlikely young people will inspire a political reversal among evangelicals in the near term. The evangelical subculture is powerful and seems to be thwarting external change on matters that are important to evangelicals. These points are driven home in a very engaging set of rigorous analyses and very thoughtful discussions.

However, the critic might question which issues are important. My earlier note that Castle, when discussing the formation of the subculture, largely omits historical efforts among white evangelicals to resist school integration hints at the possibility that their core issues extend beyond the ones most linked with the culture wars. At this writing it appears that the political behavior of young evangelicals, like their abortion attitudes, is evidence of a subculture resisting trends in mainstream culture. However, as failed policies, such as family separations at the border, heighten the salience of immigration policy (an issue that is correlated with racial attitudes), which issues matter could change. If conservative racial policies are an important part of Republican loyalty among older evangelicals, the seeds of change may still be germinating in the noncultural issues that Castle analyzes. Likewise, as climate change looms larger, environmental issues might become more central.

I raise these points not as critical flaws in the book, but rather to highlight evidence of distinctiveness among young evangelicals. And although more liberal views (compared to their coreligionist elders) on gay marriage, immigration, and the environment have not yet altered their political behavior radically, new historical events might alter the subculture. Just as happened with an evangelical political movement formed around the issue of abortion, new evangelical political movements might gain prominence around the humane treatment of immigrants or environmental stewardship or some other issue.

In Rock of Ages we have a very insightful analysis of the reasons why a political reversal among white evangelicals has not come to pass. However, having witnessed several important recent rifts within evangelicalism, scholars should continue to monitor this pivotal group of voters.