This article examines the meaning and significance of the concept of constituent power in constitutional thought by showing how it acts as a boundary concept with respect to three types of legal thought: normativism, decisionism and relationalism. The concept can be fully appreciated, it suggests, only by adopting a relationalist method. This relationalist method permits us to deal with the paradoxical aspects of constitutional founding creatively and to grasp how constituent power, as the generative aspect of the political power relationship, (...) works not only at founding moments but also within the dynamics of constitutional development. Relationalism realizes this ambition by exposing the tension between unity and hierarchy in constitutional foundation and the tension between the people-as-one and the people-as-the governed in the course of constitutional development. It contends, contrary to normativist claims, that constituent power remains a central concept of constitutional thought. (shrink)