Non-majoritarian institutions like independent agencies and central banks play a significant role in market governance in the EU, the U.S., and everywhere. For many scholars, however, delegation to non-majoritarian institutions requires the embedding in a single, coherent democratic people in order to be legitimate. This view underlies many of the strongest normative critiques of the EU, where the substantial powers of non-majoritarian institutions like the Commisison, the European Central Bank, and many decentralized agencies enjoy no such justification. I argue that this com-mon normative account relies on an unsustainable notion of cultural and political coherence as a prerequisite for legitimacy. In its place, I defend a theory of legitimacy which builds on robust claims to the common good, expertise, and value inputs—all authorized and controlled by thinner democratic procedures. Using the example of single-market governance in the EU and the U.S., I show that legitimacy assessments which presuppose strong cultural and political coherence over-state the differences between the two polities.