Recent debates in liberal political theory have sought to come to terms with the post-secular condition, characterised by deep religious pluralism, the resurgence of right-wing populism, as well as new social movements for economic, ecological and racial justice. These forces represent competing claims on the public space and create challenges for the liberal model of state neutrality. To better grasp this problem, I argue for a more comprehensive engagement between liberalism and political theology, by which I understand a mode of theorising that reveals the theological basis of modern secular political concepts. In considering two contrasting approaches to political or public theology – Carl Schmitt’s and Jürgen Moltmann’s – I argue that liberal political theory can and should open itself to a diversity of social movements and ecological struggles that pluralise the political space in ways that unsettle the boundary between the secular and religious.