This paper intersects the literature on the democratic boundary problem with the literature on the constructivist turn in political representation to show that the boundary problem broadly construed involves a distinction between ‘the problem of inclusion’ (into pre-existing demoi and their decision-making procedures) and ‘the problem of constituting the demos’ (which involves criteria for partaking in constituent power). This distinction is consistently neglected by democratic theorists. However, it has serious implications for representative democracies because the standard answers to the boundary (...) problem – the all-affected-interests principle, the all-subjected principle, and the substantive-demos principle – do not apply to the problem of constituting the demos. A new principle aimed at the latter problem is here proposed: the constructivist-representative principle. In the end, it should be clear that ascertaining who should be entitled to participate in which democratic decision requires the adoption of different principles depending on the specific demos in question and on the type of decision-making procedure involved (e.g., constitution-making-or-changing, lawmaking, policymaking, etc.). (shrink)