This book challenges received notions of ontology in political theory and international relations by offering a psychoanalytically informed critique of depoliticisation in prominent liberal, post-liberal, dialogic and agonistic approaches to pluralism in world politics. Paipais locates the temptation of depoliticisation in their labouring under the fundamental fantasy of various guises of foundationalism (in the form of either political anthropology or ontology as 'in the last instance' ground) or, conversely, anti-foundationalism (the denial of all grounds, yet still operating within a foundationalist imaginary). He argues, instead, for a formal political ontology of the void (against historicism) shot through an 'incarnate' messianic nihilism (against ethicism and teleological forms of politics). In so doing, the author offers critical readings of the messianic nihilism of Benjamin, Agamben, Taubes and Žižek by problematising the antinomian tendencies in their respective political theologies. The book argues for a version of Žižek's Badiouian politics of militancy supplemented by a proper participatory understanding of St Paul's messianic meontology and incarnational Christology as a means to reconceptualise the nexus between subjectivity, universality and political action in world politics. It will be of interest to students and scholars of International Relations theory, political theory, critical social theory and political theology.