The concept of cognitive warfare is currently gaining ground in the policy discussion and in academic research as a way of conceptualizing the ‘weaponization of the neurosciences’. Introducing the Science and Technology Studies-inspired concept of ‘neuropolitical imaginaries’ and assessing discussions on cognitive warfare launched by the NATO Innovation Hub in 2017, this article explores how the contemporary turn to the brain sciences in defense and security reimagines politics. The article argues that seeing the human mind as increasingly vulnerable to external interference redefines the nature of human agency by giving precedence to the skilful ‘cartographer’ employing neuroscientific techniques and methods for persuasion. This emerging vulnerability of the human mind reshapes security into a zero-sum game for ‘cognitive superiority’, making brain science scholars authorities in security. Finally, speaking to the literature on security expertise and science in security, the article argues that the envisaged arms race for cognitive superiority gives rise to a neurosecurity dilemma: as the neurosciences becomes entangled with security, neuroscientific practices simultaneously arise as a core vulnerability, making their work conditional upon compliance with security practices.