This dissertation is an inquiry into the relationship between political theology and the philosophical effort to establish a secular and autonomous order in which individuals govern themselves through universal laws. I argue that this project fails and explore how political theologies arise in its wake. In chapter 1, I argue that Kant’s philosophy stages a ‘trial of reason’ to establish the authority and autonomy of reason. To succeed, Kant must give an account of judgement as the reconciliation the universal and the individual. However, the trial of reason suffers two fates: Either legal procedure is flouted the new order is established through a violent act, or the verdict is deferred, and reason’s laws are legitimised by referring to an ideal of autonomy that never arises. In both cases, something is sacrificed to support rational order. In chapter 2, I show how F.W.J. Schelling responds to an autonomous and secular order by developing a political theology in which only the Church holds the key to a non-violent judgement. I then argue, in chapter 3, that Carl Schmitt develops his political theology in response to a liberal formalism which hides the sacrifices that sustain political and rational order. Here political theology springs out of the realisation that political and rational judgements always demand a sacrifice. In chapter 4, I discuss the work of Giorgio Agamben, who seeks to suspend political and rational judgement altogether. Both the political and the religious is characterised by the same ‘sacred’ logic which sustains an omnipotent, but unaccountable power of judgement. Finally, in chapter 5, I discuss the work of G.W.F. Hegel to show how the trial of reason depends on two conflicting accounts of secularisation. I end with raising some critical questions about the trial, and the political theologies that arise in its wake.