This article seeks to shed light on some of the problematic assumptions underpinning the contemporary debate over the constitutional identity of the European Union. The central claim put forward here is that the development of the European Union's constitution is significantly constrained by what Charles Taylor has described as the modern social imaginary. The constraint operates at two levels. First, modern understandings of constitutionalism typically ignore or underemphasize its dynamic and historical characteristics and its relationship with the self-understanding of political subjects. Thus, modern constitutionalism fails to acknowledge the importance of historically conditioned assumptions involved in the formation of the identities of political subjects. In short, it fails to understand constitutionalism as a 'regime'. Second, modern constitutionalism's blind-spots result in a relatively unreflective adherence to a particular type of constitutional regime: the modern economy and its associated 'consumerist' form of political citizenship.