Recent critiques of attempts to ground constitutional legitimacy in the constituent power of a strong popular sovereign have tended to focus upon the tension between strong popular sovereignty and central assumptions of liberal constitutionalism. Foremost among these assumptions are the need to reconcile disagreement regarding controversial matters of common concern and the value of the rule of law. The weakness of such critiques, however, is that they presuppose a commitment to liberal principles and values that an advocate of strong popular (...) sovereignty need not share. In this paper, I argue that recourse to liberal assumptions is unnecessary in order to demonstrate the inability of a theory of strong popular sovereignty to issue in a viable account of constitutional legitimacy. Theories of constitutional legitimacy grounded in strong popular sovereignty and constituent power, I contend, simply lack the basic resources for an adequate theory of constitutional legitimacy because they do not offer normative grounds for an assessment of whether any particular constitution is or is not legitimate. The paper is structured in three sections. Section 1 demonstrates that Carl Schmitt’s theory of constitutional legitimacy – which remains the primary source of contemporary appeals to strong popular sovereignty and constituent power – sustains a normative interpretation. Section 2 then develops a minimal constraint on an adequate normative theory of constitutional legitimacy. Finally, in Section 3, I demonstrate why a normative account of constitutional legitimacy based on strong popular sovereignty and constituent power is, at least without supplementation from normative concepts derived from a weaker conception of popular sovereignty, unable to meet this constraint. (shrink)