The success of Islamic-based political and economic movements is contrasted with lowerrates of political and economic activity in Muslim countries. The latter -- a significant “participation gap“ -- holds even after accounting for differences at the national-level and, within countries, across individuals. Based on these two trends, the argument is made that Islamic-based movements enjoy a comparative advantage when it comes to mobilizing individuals to participate in collective political and economic activities. This helps to clarify two key research questions: What are the obstacles to political and economic participation among individuals in the Muslim world? And how do references to Islam help to address these obstacles? Three existing explanations for the Islamic advantage are reviewed, each defined in terms of how it sees the obstacle to participation and the role of Islam in alleviating it. While grievance theory holds that Islam speaks to frustrations and resentments among the poor, the faith-based theory of transvaluation argues that religious beliefs create a sense of duty to serve God, regardless of the risks involved. A final theory suggests that individuals are better informed about what they canexpect from Islamic-based groups,.

A large existing literature points to a cooperative advantage within groups: if individuals share a common group identity, they tend to work together, based on a common sense of trust, extended to all group members even if they are strangers otherwise. This group-based trust appears to be naturally occurring whenever a shared group identity is commonly known among group members and salient to them. The argument is made that this group-based trust can serve as an effective substitute for more generalized feelings of trust (in “most people”) to support collective action on a similarly large scale. The concept of Islam as a group identity is developed, in contrast to traditional definitions of Islam as a personal faith, and an argument is made that regular participation in religious group activities should be used as anindicator for this Islamic identity. The empirical distinction between personal religiosity and religious identity is illustrated in data from Turkey and across the Muslim world. In addition, the validity of group activities as an indicator of Islamic identity and in-group trust is tested and confirmed.

Moving from politics to economics, this chapter investigates the role of Islam in the success of an Islamic-based business association operating in Turkey. MÜSİAD, the Independent Industrialists’ and Businessmen’s Association, was founded to bring together small- and medium-sized enterprises based in Anatolia who, because of their size and their lack of political connections, struggled to succeed in Turkey’s volatile, statist economy. Since its foundation, MÜSİAD seems to have helped these small businesses grow into “Anatolian Tigers,” apparently outpacing non-member firms. While existing theories of identity-based trade would suppose that MÜSİAD’s success rests in its ability to support a reputation mechanism among member firms or, alternatively, because of its new-found political connections to the AKP or privileged access to Islamic micro-credit, I find little empirical support for these hypotheses. Instead, using data at the firm level, I show that MÜSİAD firms succeed by relying on long-term “quasi-integrative” relationships among members, relationships which mimic the benefits of vertical integration enjoyed by larger firms. More specifically, this quasi-integration serves to protect MÜSİAD members during periods of economic volatility, although it proves to less efficient under more stable conditions, including during the period of AKP rule.

If apathy, risk, and information cannot explain the participation gap in the Muslim world, then what accounts for lower levels of political and economic activity in the region? The alternative theory that is developed here focuses squarely on interpersonal trust. It identifies two key conditions -- interdependence and uncertainty -- that, when met, make cooperation and coordination trust dependent. Different types of interpersonal trust are able to sustain collective action at different scales, with the broadest forms of cooperation and coordination requiring trust that is non-particularized, or not based on direct previous experience with the entrusted. Levels of trust and trustworthiness in the Muslim world are assessed, and the region is found to have high levels of honesty, but significantly less interpersonal trust. In contrast to some existing theories arguing that this distrust is culturally determined and unable to change, I find evidence that low trust expectations can indeed beupdated. This speaks to the potential for collective action in the Muslim world, based on the high levels of trustworthiness there, if only individuals can learn to trust one another.

What can explain the rapid rise of Islamic politics in Turkey, a historically secular country? Many observers assume that the success and sustained popularity of the Justice and Development Party (AKP) reflects a religious resurgence in Turkey. But when this presumption is directly tested, evidence indicates that Turkish piety may actually be declining over time. This highlights the importance of statistical tests,leveraging variation across individuals, space, or time: they have the potential to overturn widely held assumptions and reopen key questions about the world around us. In finding no evidence of a religious resurgence in Turkey,an alternative explanation is needed. I introduce my trust-based theory of Islamic mobilization, explaining how references to Islam prime feelings of trust among those with a salient religious group identity, and how this group-based trust operates as an effective substitute for more generalized feelings of interpersonal trust, which are largely absent in Turkey and in many other Muslim countries. I contrast my trust-based theory with existing theories of Islamic-based politics and economics and preview the findings of the book, wherein I dismiss the existing explanations and offer support for mine.

If there is no evidence of a religious resurgence in Turkey, what can explain the rise and sustained success of Islamic-based parties there? To understand the popularity of Islamic parties, like the AKP, a broader view of the Turkish electoral system as warranted: alongside the rise of the AKP came a sharp decline in electoral volatility -- vote swings between parties from election to election -- and in the share of votes that were wasted, cast for parties that failed to secure a seat in a given district. I argue that these two trends are not coincidental but are both based on matters of trust: low levels of interpersonal trust makes it difficult for voters within districts to vote strategically and successfully coordinate their individual votes into meaningful outcomes; but this trust problem is effectively solved within religious voters, to the comparative advantage of Islamic parties. Moreover, the ability of religious voters to coordinate their support for Islamic parties, and to do so consistently, helps to make these parties an attractive target for strategic votes from distrusting, conservative voters, even if they are secular. Analysis of panel data from the Turkish case provides empirical support for both hypotheses.

The conclusion begins by exploring questions of internal and external validity. In the latter case, the concept of religious group identity is applied to faiths other than Islam and is found to extend to other egalitarian faiths, including Judaism and Buddhism. In addition, cross-national data on vote volatility confirm that the trust problem invoter coordination extends beyond the Turkish case. Delving into some out-of-sample predictions, I consider where in the Muslim worldIslamic groups might be particularly successful, based on a combination of low trust and salient Islamic identity. I also explorewhat mightexplain the strange combination of low trust and high honesty in Muslim countries. To address this trust deficit, I suggest that over-bearing institutions may play a key role in not allowing citizens to learn who among them can really be trusted. Finally, I consider what factors from within my theory could explain the eventual decline of Islamic-based groups, in Turkey and elsewhere, before posing some questions for future lines of inquiry.