The Islamic State – which I refer to by its Arabic acronym, Daesh – has many of the attributes of a state. To call Daesh an insurgency gives too little attention to its ambitions for territorial control, and to call it a state gives it a false air of legitimacy, but it falls somewhere between the two. Daesh, I contend, is an unusual state indeed because it does not believe in state sovereignty. Its ideology puts it fundamentally at odds with the norms of Westphalian sovereignty that have developed in the international system over the past three centuries.