Religious parties representing many religious denominations are increasingly common around the world. However, studies of parties based in Christian (Anna Grzymala-Busse, Nations under God, 2015) and Islamic (Jillian Schwedler, Faith in Moderation: Islamist Parties in Jordan and Yemen, 2006; Charles Kurzman and Ijlal Naqvi, “Do Muslims Vote Islamic?” Journal of Democracy, 21 [2], 2010) traditions have rarely focused on building common insights regarding their origins, tactics, and successes. Luis Felipe Mantilla’s book attempts to bridge this scholarly gap by focusing on a key question: How and under what conditions do political parties mobilize religion? It answers this question by offering innovative measures of religious mobilization and religious parties, and a theoretical framework, and an empirical analysis that spans Catholic and (Sunni) Islamic religious traditions.

The author begins by defining religious mobilization as the totality of mobilization along three distinct dimensions: religious identity, religious doctrine, and links with religious associations (table 1.1, p. 27). He identifies the specific party choices and practices that indicate low (secondary) and high (primary) levels of mobilization on each dimension. He then combines party mobilization levels across these dimensions, yielding a theoretically rich range of overall religious mobilization. Using this measure to compare religious mobilization in Catholic and Sunni Islamic countries, he finds that parties in Catholic countries engage widely in low levels of religious mobilization, whereas those in Sunni countries mobilize less frequently but at much higher levels (pp. 31–33). Interestingly, electoral success is highest for parties that engage in low levels of religious mobilization in both Catholic- and Sunni-majority countries. In what will be considered the most controversial decision in this book, these mobilization levels are then used as alternative criteria to classify parties as religious or not (table 1.2, p. 28).

Using the most permissive definition, a party is classified as religious if it engages in religious mobilization on at least one dimension at a secondary level. Under the moderately permissive definition, a party is considered religious if it engages in secondary mobilization along all three dimensions or in primary mobilization along at least one dimension (pp. 26–29). Finally, using the strictest definition, a party is classified as religious only if it engages in primary levels of mobilization along all three dimensions. The author argues that using these alternative criteria to classify religious parties allows scholars to test how sensitive theories related to religious parties are to the definition used to identify those parties. Chapter 1 then lays out a theory explaining the conditions under which religious parties come into existence and succeed in elections.

Mantilla argues that two factors—the internal structure of religious communities and the state institutions governing elections and religion—influence religious mobilization levels. When clerics have little authority and are unable to coordinate their actions, lay activists are highly fragmented, and state regulatory and electoral environments are permissive, parties will engage in the highest level of religious mobilization. Conversely, when religious communities are led by clerics with concentrated religious authority, and state regulatory and electoral environments are less permissive, parties will engage in the lowest level of religious mobilization. This is because powerful clerics are less interested in risking control of their religious message and authority by collaborating with political parties operating with different goals, whereas lay activists are motivated to cooperate with parties to increase their own influence in an environment where they must compete with other legitimate religious authorities (pp. 37–40). State regulation of religion matters because it influences what forms religious mobilization can take, while electoral institutions influence how easy or hard it is to translate religious mobilization into political representation. Finally, Mantilla argues that although these factors yield more concrete predictions regarding the presence of religious parties, their predictability regarding electoral success is lower because other factors also mediate electoral success.

To test these arguments, the author analyzes the impact of religious structure and state regulation of religion and electoral permissiveness on (1) the existence of religious parties in a country in a given year and (2) the total number of legislative seats won by all religious parties in a year in a country, using data from 22 Catholic- and 18 Sunni-majority countries from 1990 to 2012. These tests are done using three alternative sets of religious parties based on their religious mobilization level. Mantilla finds that results vary substantially depending on how one defines religious parties, thus confirming his larger point that the definition of religious parties is itself a crucial choice that influences empirical support for any subsequent theory relating to those parties.

Given the limitations of operationalizing complex concepts such as the internal structure of religious communities and the relative influence of clerics versus lay activists for quantitative analysis, Mantilla conducts a comparative historical study of Mexico (a Catholic-majority country) and Turkey (a Sunni-majority country) to examine the validity of his theory. The next four chapters trace the trajectory of religious mobilization in these two countries over a century, identifying the values that the two explanatory factors—religious community structure and regulatory and electoral institutions—take on at different times and their influence on parties’ incentives to select a certain level of religious mobilization. These chapters provide a convincing, in-depth, and persuasive test of the book’s theoretical framework. However, they pay less attention to the earlier question raised in the book of whether using alternative definitions of religious parties changes the empirical support for the theory.

The book makes three important contributions. First, it highlights the importance of analyzing the internal dynamics of religious organizations and communities in understanding their effect on political actors, including political parties. Previous research has explained varying levels of the political mobilization of religion by religious parties and organizations as stemming from differences in the modernization levels of societies (the secularization thesis; see David Smith, Religion and Political Development, 1970) or in the beliefs and traditions of different religions (the civilizational thesis, see Bernard Lewis, What Went Wrong? 2002). Scholars have increasingly emphasized how the extent of state regulation of religion (see Jonathan Fox, Political Secularism, Religion and the State, 2015) and the degree of competition between religious organizations (the religious marketplace thesis; see Roger Finke and Rodney Stark, “Religious Choice and Competition” American Sociological Review, 63 [5], 2013) affect the incentives of religious and political actors to mobilize religion in the political sphere. The author adds to this scholarship by highlighting how the relative influence of clerics and lay preachers and their fragmentation affect the opportunities other political actors have to leverage religion for political purposes.

Second, this book adds to the ongoing debate about how to appropriately define religious parties. Most scholars currently use the ideological principles that religious and nonreligious parties articulate in their founding documents or election manifestos to classify them programmatically (e.g., Kurzman and Naqvi, “Do Muslims Vote Islamic?”). They then study the conditions that motivate religious (or other) parties to subsequently change their platforms and tactics. This is the approach taken by, for example, the literature on moderation theory, which breaks down subsequent change into ideational and strategic change (for example, see Schwedler Faith in Moderation, 2006; Carrie Wickham, The Muslim Brotherhood: Evolution of an Islamist Movement, 2013; and Kurzman and Naqvi, “Do Muslims Vote Islamic?”). Party choices to change platforms or form alliances with religious or other associations can result from either ideational and strategic changes or both in parties. Researchers in this camp, including myself, would have liked to see the author present an analysis that used his finely grained measure of religious mobilization as the outcome to be explained. Instead, he uses the time-varying choices of doctrinal and policy positions and alliances with associations to generate a time-varying identification of a party as a religious party. In other words, the author argues that if a party walks the religious walk in terms of mobilizing religion at a certain time, it is a religious party at that moment in time, no matter its founding ideology.

This definition of a de facto religious party raises larger questions about whether changes in policy platforms or alliance tactics accurately reflect a fundamental shift in the nature of a party. The PML-N party in Pakistan personifies this conundrum. It presents itself as a conservative, not religious, party. Yet its actions include supporting a law that would have effectively implemented sharia law in 1998, passing laws protecting women in mixed-gender workplaces in 2010, and criminalizing domestic violence in 2016 (Christophe Jaffelot, Pakistan at the Crossroads, 2016). The first policy is strongly supported by other religious parties and organizations in Pakistan; the latter two are strongly opposed by them. The question is, do these policies reflect deep changes in the PML-N’s nature as a religious or nonreligious party, or do they reflect time-varying tactics that the party adopted because of changing political imperatives? The author classifies this party as a religious party using the moderate level of religious mobilization to define religious parties (p. 28).

Third, and finally, by focusing on changes in the frequency and intensity with which doctrine is emphasized, the frequency of religious policy proposals, and the alliances with religious organizations, Mantilla successfully outlines a strategy that allows scholars to transcend religious traditions in the study of religious mobilization. Given the global ascendance of religious parties, this is a valuable contribution to the toolkit of scholars.