The article discusses how we might understand solidarity as the organizing concept behind the institutionalization of social rights. I argue that writing solidarity into social rights constitutionalism carries productive tension into constitutional thinking because it disturbs the smooth passage from civil to political and finally to social rights. Marshall's influential argument that social rights are continuous to civil and political rights has become both the grounding assumption in constitutional theory and at the same time the most obvious lie in the constitutional practice of advanced capitalist democracies, clearly belied in EU constitutional practice under austerity. I explore the various attempts to accommodate the continuity of civil, political, and social rights in the face of the contradictory articulation of social democracy and capitalism before undertaking something of a defence of the antinomic significance of social rights constitutionalism, and probing what mileage might be left in ‘exploiting’ the contradiction between capitalist interests and social rights.