Political mobilization tends to take different forms in contemporary Catholic- and Sunni-majority countries. Luis Felipe Mantilla attributes this dynamic to changes taking place in religious communities and the political institutions that govern religious political engagement. In How Political Parties Mobilize Religion, Mantillaevenhandedly traces the emergence and success of religious parties in Mexico and Turkey, two countries shaped by assertive secular regimes. In doing so, he demonstrates that religious parties are highly responsive to political institutions, such as electoral laws, as well as to the structure of broader religious communities. Whereas in both countries, the electoral success of religious mobilizers was initially a boon for democracy, in Mexico it was marred by political mismanagement and became entangled with persistent corruption and escalating violence. In Turkey, the democratic credentials of religious mobilizers were profoundly eroded as the government became increasingly autocratic, concentrating power in very few hands and rolling back basic liberal rights. Mantilla investigates the role religious mobilization plays in the evolution of electoral politics and democratic institutions, and to what extent their trajectories reflect broader trends in political Catholicism and Islam.