This chapter interrogates the role of ideas in Neil Walker’s theory of constitutional pluralism. The first section of the chapter situates Walker’s work in relation to the body of state-centric constitutional theory. It shows the steps Walker takes to attach his theory to past constitutionalisms, and it argues that the focus on theory leads him to blank out the question of state practice. The second section considers the ideas and conceptual moves that pass from the body of constitutional theory to Walker’s theory. In the third section, the chapter shows that the continuity between past and present formats of constitutional theory rests upon a historically specific intuition of political life. It argues that the changes Walker makes to his theory can be explained in terms of the passing of a specific historical conjuncture, in which law could transcribe politics and keep economic rationality at bay.