What is the relationship between security and secularization in International Relations? The widespread acceptance of secularism as the paradigmatic framework that underlies the study of world politics has left this question largely unexplored. Yet, the recent challenges to the secularization thesis and the growing attention that is being devoted to questions of religion and secularism in international politics increasingly suggest the importance of undertaking this investigation. This article takes up this task in three main steps. First, it will explore how the limits of a widely accepted but nonetheless problematic account of the emergence of the modern Westphalian nation-state contribute to a dominant underlying assumption in security s...