Counter-extremism is the most dynamic part of UK counterterrorism policy. This article examines Prevent, the flagship counter-extremism programme, through a statetheoretical lens. It addresses questions of state institutionality, state power, and statesociety relations. It argues that counter-extremism aims to avert the possibility of a political future by repressing the formation of non-liberal political subjectivities. To achieve this, Prevent divides society along political lines; aligns welfare institutions with the security apparatus; mobilises society in a security endeavour; exercises an authoritarian 'pastoral' power; replaces trust with generalised suspicion; and construes subjectivities without capacity for historical agency. Therefore, Prevent is a political paradox: an anti-liberal project aiming to secure and perpetuate liberalism.Introduction: From community to society (and from society to the state)Since its strategic relaunch in 2011, counter-extremism has been the most dynamic part of UK counterterrorism policy. It is prominent in public discourse, in institutional and strategic development, and it expands the boundaries of where security policy can apply and what it can achieve. This article examines the institutional structure, function, and rationale of Prevent, Britain's flagship counter-extremism programme; and appreciates them in the light of political and state theory. In doing so, it offers a novel approach to counter-extremism, a wider vistaand deeper critiquethereof.Critical accounts of Prevent tend to conceptualise it as a relation between the state and British Muslim communities. They find Prevent is 'construing the Muslim community as the actionable site of counterterrorism' ([82]: 7). They theorise it as a an intervention in state-community and inter-community relations [84]; as a project that maps the Muslim community [3]; coercively intervenes in the realm of theology [54]; https://doi.