The constitutional referendum is often conceptualised as the ultimate institutional expression of popular sovereignty. However, ‘direct democracy’ is viewed apprehensively by many political and legal theorists, particularly republican scholars. They argue that referendums risk engendering a dangerous ‘populism’ while detracting from the deliberative and moderating virtues of parliamentary democracy. In this paper, I defend the political value of the constitutional referendum from within republican theory, arguing that there is a misplaced focus on parliamentary supremacy within much of the literature on ‘political constitutionalism’. However, I argue it should be valued neither as a mechanism for giving expression to popular will, nor as an intervention by the mythologised ‘constituent power’ – or indeed, contra Tierney, as a ‘sovereign’ exercise in any sense. Rather, it has two main, overlapping virtues: first, its role in facilitating the contestation and checking of executive power in the area of constitutional change, and secondly, its instrumental role in fostering a wider culture of civic participation.