Turkey is currently at the center of a global debate over the place of religion in politics. As the most advanced Muslim democracy and a former assertively secular republic, the country’s ongoing renegotiation of its identity will inform conversations about the resurgence of religiosity from Latin America, where charismatic Catholicism and Pentecostalism have taken root, to the United States, where Evangelical Christianity influences policy, prose and the choice of presidential candidates. Unfortunately, despite growing interest in the resurgence of religiosity and the global significance of this topic, we have a difficult time understanding the role of religion because we lack a good way to capture this phenomenon across countries and across time. Moreover, by focusing on formal constitutional texts, many authors miss important informal norms and ongoing practices operating at both the state and societal levels. The case of Turkey indicates that informal rules and customs are key to understanding the role of religion in society and politics. The country’s militantly secular constitution belies growing endorsement of a more public role for Islam and a decade of support for politicians who openly promote Islamic values. Drawing on the Turkish case study, this paper shows how informal norms can be incorporated into empirical measures of religious governance, and what happens when conflicting formal and informal policies and norms are operating within the same state. I rely on qualitative case study analysis and develop and apply an original measure of political religiosity.