The Introduction sets the framework for the analysis and introduces the central research question of The Politics of Religious Party Change: when and why do religious parties become less anti-system? This chapter explains the significance of the question, discussing the rising prominence of religious parties globally and the need to better understand the dynamics of change in these parties. Likewise, the Introduction details the methodology used in this book and the six empirical cases: The Egyptian Muslim Brotherhood, Tunisian Ennahdha, Turkish AKP, German Center Party, Italian PPI, and Belgian Catholic Party.

What do the religious institutional structures look like in Catholicism and Sunni Islam? In order to trace how religious institutional structures may shape the early evolutions of religious parties, this chapter explores the historical development of structures of religious authority and how they looked when religious parties arose. The focus of the analysis for each religion varies to reflect the historical trajectories of their religious institutions and what such different trajectories mean for the analytical narrative of this book. The analysis proceeds in chronological order and begins with Catholicism to be followed by Sunni Islam. In the case of Catholicism, the focus is less on the evolution of religious institutions and more on how divergence from orthodoxy and orthopraxy are handled within the Catholic Church. As the religious authority in Catholicism, the Church’s handling of divergences is key to understanding how it dealt with the rise of Catholic parties. In the case of Sunni Islam, the focus remains on the historical evolution of religious authority, paying close attention to the parameters of major shifts in the eleventh and early twentieth centuries.

The Politics of Religious Party Change addresses the timely question of ideological change and secularization of religious political parties and asks, when and why do religious parties become less anti-system? In a comparative analysis, this book traces the striking similarities in the historical origins of Islamist and Catholic parties in the Middle East and Western Europe, chronicles their conflicts with existing religious authorities, and analyzes the subsequently divergent trajectories of Islamist and Catholic parties. Religious parties are embedded in distinct religious institutional structures that shape their actions as they chart their paths in electoral politics. Counterintuitively, the book finds that centralized and hierarchical religious authority structures – such as the Vatican – incentivize religious parties to move in a more pro-system, secular, and democratic direction. By contrast, less centralized religious authority structures such as in Sunni Islam create a more permissive environment for religious parties to operate as anti-system parties hostile to democracy and secularism.