This report analyzes how al-Qaeda and the Islamic State construct the notion of apostasy as a tool for legitimizing intra-Muslim violence. Using data from the TITAN Project, it examines how both organizations deploy doctrinal concepts such as ḥākimiyya ḥ , al-walāʾ wa-al-barāʾ, and tawba to define moral boundaries, delegitimize political and religious authorities, and justify coercion against Muslim actors framed as deviant or heretical.
Drawing on data from the TITAN Project, the study demonstrates that while al-Qaeda and the Islamic State draw on a shared theological repertoire, they operationalize apostasy in markedly different ways. Al-Qaeda advances a graded and strategic architecture that allows for differentiation, persuasion, and conditional reintegration, whereas the Islamic State adopts a totalizing and coercive model centered on categorical denunciation and enforced loyalty. By systematically comparing these two architectures of apostasy, the report shows how doctrine is translated into communicative strategy and how theological concepts are instrumentalized to serve distinct organizational priorities.