This article explores the conditions under which religious organizations push for democratization by addressing variation in support for democracy among Catholic Church authorities in South America. It argues that this can be best explained by leveraging key concepts used in the study of social movements: cultural frames, mobilizing resources, and political opportunity structures. This approach yields counter-intuitive insights about the role played by the Second Vatican Council, the size of national churches, and the crucial role of political parties. The empirical argument is formulated in terms of necessary and sufficient conditions, and tested using fuzzy-set Qualitative Comparative Analysis.