In his provocative article, Mark Tushnet asks whether United States v. Lopez signals a major constitutional shift in federalism-- specifically in the allocation of political and regulatory power between State and Nation. Tushnet uses the Lopez problem to test the adequacy of the political theory that Bruce Ackerman terms “dualist democracy,” delineated in Ackerman's work in progress. Like many other reviewers, Tushnet finds Ackerman's theory wanting in crucial respects.My response takes two tracks. First, I will argue that the import of Ackerman's theory is better understood and evaluated when it is considered more as a work of political philosophy and political theory rather than as a work of law or jurisprudence. Ackerman should be understood as participating in two distinct conversations: The first, at the core of political philosophy, is concerned with the possibility for human freedom. The second is central to political theory, namely, what kind of governmental structures and organization will permit the realization of particular philosophical commitments. I think Ackerman is making startlingly original and valuable contributions in both realms. In the first part of this commentary, I will situate Ackerman's theory most pointedly as a direct response to Hannah Arendt.