What role, if any, does religious ideology play in the Islamic State’s (IS) violence and governance strategies? Given the organization’s name alone, the role of religious ideology in the group’s behavior—from challenging its enemies through a combination of violent tactics to undertaking intensive state-building projects—has seemed paramount. This essay, however, argues that the Islamic State’s governance and warmaking strategies are neither unique to the Islamic State nor are they particularly Islamic, as these behaviors are part of revolutionary warfare strategy that crystallized under, and were predominantly implemented by, leftist rebel groups during the Cold War. The Islamic State’s approach is thus a jihadist interpretation of this revolutionary warfare strategy with origins in leftist rebel groups. This essay describes the nature and origins of revolutionary warfare, as well as its spread from leftist and anticolonial movements across ideological categories to jihadist groups. It then demonstrates the parallels in both violence and governance between the Islamic State and Cold War leftist revolutionaries. The essay concludes with a discussion of the role of a religious ideology in terms of the Islamic State’s strategic approach, as well as the implications for jihadist warfare in the future.