This article situates H. Morgenthau�s thought in the context of post-foundationalist theorisations of the difference between politics and the political. In doing so, it shows how Morgenthau�s sophisticated realism refused to circumscribe the antagonistic dimension of politics and introduced the study of international politics as a struggle with negativity, temporality and contingency in the wake of the crisis of foundationalism in late modernity. Morgenthau�s tarrying with the negative is primarily revealed in his irresolvable tragic oscillation between Nietzschean scepticism and Kantian moralism. Nevertheless, due to its antinomic premises, Morgenthau�s tragic vision of politics can still be viewed as stopping a step short of its full-blown critical potential. It is not the purpose of this article, however, to award or withhold credentials of criticality but to recast Morgenthau�s theory of the political as an instructive, albeit inconclusive, attempt at a post-foundational political ontology. This may, eventually, serve a purpose far broader than restoring classical realism�s latent reflexivity; it may prompt an argument about the conditions and challenges involved in practising international theory as a constant critique of depoliticisation.