The article presents the normative case for the new Commonwealth model as a novel third way of organizing basic institutional arrangements in a democracy and an alternative to the conventional dichotomy of legal or political constitutionalism. In so doing, it engages with the latest contributions to the debate about the merits of judicial review, and argues that the new model radically and compellingly permits a form of “proportional representation” among the best arguments for and against the practice rather than the “warts-and-all” of the traditional either/or approach. In this way, the new model is to forms of constitutionalism what the mixed economy is to forms of economic organization: a distinct and appealing third way in between two purer but flawed extremes. Just as the mixed economy is a hybrid economic form combining the core benefits of capitalism and socialism while minimizing their well-known costs, so too the new model offers an alternative to the old choice of judicial supremacy or traditional parliamentary sovereignty by combining the strengths of each while avoiding their major weaknesses. Like the mixed economy's countering of the lopsided allocation of power under capitalism to markets and under socialism to planning, the new model counters legal and political constitutionalism's lopsided allocations of power to courts and legislatures respectively.