The world order is undergoing significant changes, marked by growing contestation of the liberal international order (LIO). This article examines how these shifts are reflected in the way international security is conceptualised. It analyses changes in security conceptualisations at the level of both discourses and practices. At the discursive level, the article examines speeches by the five permanent members (P5) of the UN Security Council. It shows increasing contestation among the P5 over three interconnected dimensions of security: whether external interventions constitute security threats; whether individuals threatened by their own governments qualify as referent objects of security; and what role the UN should play as a subject providing security compared to host states. At the level of practice, the article analyses the evolution of UN peace operation mandates. It finds a gradual shift towards more state-centric security conceptualisations, reflected in a rise of minimalist mandates and a relative decrease of human-centric tasks. The findings indicate that the decline of the LIO is accompanied by growing competition in security understandings and a partial reassertion of state-centric approaches in both discourse and practice.