Abstract: The twin concepts of constitutionalism and democracy, which offer a complex template for the structural organisation of a polity, can be understood in terms of a dialectic of complementary but competing values, values represented by responsiveness to an existing order and innovation towards a potentially new order. Recognising this necessarily dynamic relationship, an essentialist reading of a constitutionalisation of the demos is abandoned, and an examination of the extent to which the dialectic can credibly or legitimately be played out in a supranational ‘community’ and in the context of an emerging transnational civil society can be undertaken. Rather than seeking credibility or legitimacy through the rationalisation of a community by an ethical consensus as in some forms of republicanism and communitarianism, the dialectic opens up the norms and boundaries of the polity and leads to an understanding of the ‘community’ in less rigid and more diffuse, even plural, terms. Once understood in this way the possibility emerges for legitimacy to be pursued through a public sphere enlarged by a context-transcending constitutional discourse mediated by transnational civil society. Alternatively the normative ‘openness’ of the polity might be prioritised and with it the uncertainty/fluidity of the constitutional arrangement itself; in this way the legitimate pursuit of constitutionalism is understood in terms of a never-ending agonistic struggle or experimental practice.