This article examines the challenges extremist ideologies, particularly Jihadism, pose to open societies. Jihadist ideology manifests through what is described as an ideocracy—a theocratic autocracy that seeks to establish a state based on a strict interpretation of Islam and its sources. Such ideologies fight not only against non-Muslims but also against Muslims who reject their Islamist views. To counter this global threat, it is essential to deconstruct both the ideological content and the concept of the state promoted by Jihadism, focusing on its normative ideas of order. The concept of a closed society, exemplified by the IS caliphate, is characterized by the goal of establishing a theocratic state in the name of God, where violence and struggle against enemies are justified as divine mandates. This ideology employs a rigid friend-enemy dichotomy, fostering internal unity and legitimizing authoritarian rule. In contrast, open societies tolerate diversity and “the other,” emphasizing dialogue and religious interpretation to manage conflicts. The article highlights that the closed society model, such as IS’s caliphate, represents a fundamentalist temptation within every religion, and underscores the importance of protecting open societies from extremist threats like IS-Jihadism.