Rawls and Schmitt are often discussed in the literature as if their conceptions of the political had nothing in common, or even referred to entirely different phenomena. In this essay, I show how these conceptions share a common space of reasons, traceable back to the idea of public reason and its development since the Middle Ages. By analysing the idea of public reason in Rawls and in Schmitt, as well as its relation to their theories of political representation, I show in what way Schmitt's concept of the political cannot be divorced from an idea of justice, while, conversely, Rawls' conception of justice cannot be divorced from a theory of the political. In that way this paper thematizes the internal relation that each theory establishes between justice and power, deliberation and decision, and consensus and disagreement.