The question of the legitimacy of judicial review of legislative and to a lesser extent, administrative, action is a perennial theme in constitutional studies. However recent years have seen particular attention to this question in political theory, notably in the work of Jeremy Waldron and Richard Bellamy, who have provided robust normative defences of legislative supremacy in questions of constitutional design. Both of their approaches, however, through their insistence on ‘disagreement all the way down’, have come up against the challenge that their positions are ultimately self-defeating. This paper attempts to take up this challenge to theories of political constitutionalism by adding an additional layer of moral arguments to defend legislative supremacy through a minimal theory of legitimacy. As it relies on providing moral reasons for resisting a move from political to legal constitutionalism only in those jurisdictions where it is actually currently practiced, as opposed to a more general argument as to why political constitutionalism is the most legitimate form of constitutional design in constitutional democracies, it is therefore only a partial defence of political constitutionalism. However, given that the defences of political constitutionalism are self-defeating on their own terms, the paper concludes that the conditions of this partial defence are a necessary prior to theoretical defenses of legislative supremacy.