For decades, constitutional theory has been haunted by the problem of disagreement: the reality that we are deeply divided on fundamental questions of justice and the good society. Theorists have generally responded to the problem of disagreement in one of two ways. One approach minimizes the extent to which constitutional theories rely on controversial moral premises and instead grounds constitutional theories in widely endorsed social practices. The other generally discards any social practices that reflect disagreement with the moral views that the theorist holds.
Neither approach is sound. Constitutional theory requires both controversial moral claims and attention to social practices; it requires both ideal and practical theory. Indeed, we can see how to address the seemingly modern problem of disagreement by attending to the work of an ancient constitutional theorist: Cicero. Despite being the subject of intense scholarly interest outside the legal academy over the last few decades, Cicero’s work has been almost entirely overlooked by American constitutional theorists. But if we examine, refine, and revise his arguments about ideal and practical constitutional theory, we will find that the two dominant approaches to the problem of disagreement proposed by American constitutional theorists are mistaken.
Because constitutional theory necessarily makes strong moral claims, it is not well-suited to mitigating the effects of disagreement, even as it must take into account non-ideal social practices. Rather, the task of ameliorating the problems stemming from disagreement falls to constitutional design: the enterprise of constructing a constitution that can channel disagreements productively, forge consensus, and produce a stable constitutional order. The failure to distinguish between constitutional theory and constitutional design when addressing the problem of disagreement has led to deep confusion within constitutional theory. Mitigating the problem of disagreement is a task of constitutional design, and whether that task succeeds depends on our role acting within that design as citizens, not as theorists.