The article explores the contemporary Islamist project - constituted by those that mobilize to restructure public life according to Islamic norms - in the context of the 2011-2013 "Arab spring”. It has two interrelated aims. First, it aims to empirically explore changing interactions between Islamist mobilization in politics and in society, and examine the position state organizations have within these changes. Second, it aims to apply insights of studies on social movements and contentious mobilization in the analysis of these interactions. The articles main contentions are, first, that in their practice Islamist movements face a dilemma how to react to a context that is ever more strictly divided between a social and political arena: either mobilization is aimed at societal change through organizing as social associations, or it is aimed at maximizing political influence through organizing as political parties. Irrespective of what their ideology is, all movements face the dilemma how to reconcile a vision of a complete Islamic system with day-to-day realities. Second, I argue that common strategies addressing the perceived “secularity” of state bureaucracies and public organizations can be the basis of a shared goal for mobilization and thereby ensure the unity of the Islamist project. A specific debate within studies on collective mobilization – relating to the social process of “upward scale shift” – is then used in an analysis of how these state organizations can influence the relation between Islamist mobilization in society and politics. I substantiate these claims through a paired comparison between Syria and Tunisia. The comparison builds on, first, extensive fieldwork over the course of four years in the Arab world (mainly Syria, Tunisia, Turkey and Jordan) in which around 180 individuals have been interviewed. Second, it draws on a content analysis of primary sources from Islamist associations, state organizations, and individual autobiographies of (Islamist) actors; third, it uses secondary sources from local, Arab and international newspapers as empirical basis for the analysis.