In this article, I engage with Derrida’s deconstructive reading of theories of performativity in order to analyse Max Weber’s sovereignty–legitimacy paradigm. First, I highlight an essential articulation between legitimacy and sovereign ipseity (understood, beyond the sole example of State sovereignty, as the autopositioned power-to-be-oneself). Second, I identify a more originary force of legitimation, which remains foreign to the order of performative ipseity because it is the condition for both its position and its deconstruction. This suggests an essential fallibility of the performative, which implies a ‘mystical’ legitimacy and a paradoxical, divisible and self-differential representation of sovereignty. The structural differentiality of legitimacy and sovereignty signifies an irreducible coloniality of law and language, but also suggests the possibility of an unconditional resistance located in the radical interpretability of the law, beyond determined representations of powers, dominations, sovereignties or resistances. This reflection is triggered by a reading of Cynthia Weber’s theory of ‘performative states’, describing sovereignty under the form of an impossible ontology, which leads me to elaborate the notion of legitimation-to-come as a non-ontological ‘concept’: this notion of unconditional legitimacy, beyond sovereignty, binds beliefs and phantasms to the unpresentable force of the event. Pursuing the efforts of scholars such as Rob Walker and Cynthia Weber, I sketch the implications of this archi-performative legitimacy regarding the methodological protocols of International Relations and sociology, in view of elucidating the persistent ontological presuppositions of these disciplines.