As my work has argued previously, European integration enjoys an “administrative, not constitutional” legitimacy. This view is in obvious tension with the deeply-rooted conceptual framework—what we might call the “constitutional, not international” perspective—that has dominated the public-law scholarship of European integration over many decades. Although the alternative presented in my work breaks from that traditional perspective, we should not view it as an all-or-nothing rejection of everything that has come before it. The administrative alternative can be seen, rather, as providing legal-historical micro-foundations for certain theories that also emerged out of the traditional perspective even as they too are in tension with it. I am referring in particular to Joseph Weiler's classic notion of European “equilibrium”—now updated as “constitutional tolerance”—as well as Kalypso Nicolaïdis's more recently developed theory of European “demoi-cracy” on which this article focuses in particular. The central idea behind the “administrative, not constitutional” interpretation—the historical-constructivist principal-agent framework rooted in delegation, as well as the balance demanded between supranational regulatory power and national democratic and constitutional legitimacy— directly complements both theories. The administrative alternative suggests how the relationship between national principals and supranational agents is one of “mediated legitimacy” rather than direct control. It has its origins in the evolution of administrative governance in relation to representative government over the course of the twentieth century (indeed before). By drawing on the normative lessons of that history—notably the need for some form of national oversight as well as enforcement of outer constraints on supranational delegation in order to preserve national democratic and constitutional legitimacy in a recognizable sense—this article serves an additional purpose. It suggests how theories of European equilibrium and demoi-cracy might be translated into concrete legal proposals for a more sustainable form of integration over time—a pressing challenge in the context of the continuing crisis of European integration.