This article engages with the emergent ethnographical study of secular practice by focusing on how local bureaucracies manage the Muslim public presence in the Netherlands, particularly the construction of new mosques and the amplifying of the Muslim call to prayer. We argue that what started as the ‘Islam debate’, itself provoked by growing populist articulations of the fear of Islam, has gradually developed into a conflict in the practice of local governance about the meaning of secularism. Whereas the public and political debate about mosque issues is often dominated by what we call a ‘culturalist’ or ‘nativist’ form of secularism, in practice bureaucrats are often led by a ‘constitutional secularism’ that protects the constitutional rights of Dutch Muslims. Thus, in its ractical application, constitutional secularism is one way of tackling Islamophobia and protecting the rights of religious minorities in general. Moving beyond the genealogical study and the deconstructivist critique of secularism by such authors as Talal Asad and Wendy Brown, we show that the ethnographic study of actual secular practice remains crucially important to avoiding monolithic text-based understandings of the secular as inherently dominating the religious.