In Australia, a technocratic minimalist approach to constitutional interpretation leaves little space for what has recently been described as a ‘democratic’ or ‘social’ ‘constitutional imaginary’. The ‘big picture’ of what a constitution is, and why it matters, is systematically reduced to a ‘strict and complete legalism’ that shows little interest in the social and cultural functions of a constitution in the modern world. The ‘dual citizenship’ cases (2017–18), concerning s 44 of the Australian Constitution, provide an exceptional case study. The High Court of Australia’s narrow positivism shielded it from criticism, but at a high cost to Australia’s democratic and social fabric. This article argues that, at a time when the rule of law and the public sphere is under threat as never before, we can and should expect more of our peak legal institutions. A constitutional court without a broader commitment to constitutionalism imperils the legitimacy of the whole constitutional order and of the public sphere.