Abstract: The idea of judicial dialogue entered into scholarly discussion in the late twentieth century and is used in connection with different phenomena at the transnational and domestic levels. In the transnational context, it refers to exchanges among courts and judges that belong to different national and international legal regimes. In the domestic context, judicial dialogue refers to interaction between courts and other branches of government, particularly legislatures. Each phenomenon is associated with a form of politics. Transnational judicial dialogue occurs in a literal sense when judges communicate and network with each other, but it also occurs in a figurative sense when judges engage in comparative legal research and consider each other’s work. Either way, it can resemble a specialized form of international relations, in which courts seek to bolster their own standing by affiliating themselves with more prestigious peers, and to exercise soft power and influence over less prestigious peers. Transnational dialogue is often opaque or invisible to outsiders and usually lacks domestic political ramifications. In a handful of settings, however, judges who make conspicuous use of foreign law by explicitly citing it in high-profile or controversial opinions can expect to face normative criticism for doing so.Dialogue at the domestic level is associated with alternative forms of judicial review that give legislatures the power to override or avoid judicial rulings of unconstitutionality. Such institutional configurations are said to strike a balance between legislative and judicial supremacy, and to take the sting out of the charge that constitutional courts are inevitably ‘countermajoritarian.’ Scholarly use of the dialogue concept envisions a discursive form of constitutional politics that is differentiated from, and superior to, the usual politics surrounding judicial review. However, it is unclear whether such a distinctive and elevated species of politics can be achieved in practice. On the one hand, if ‘dialogue’ is defined in a thin fashion as including any back-and-forth on constitutional questions between legislatures and courts, the concept becomes so broad as to be indistinguishable from ordinary politics. On the other hand, if ‘dialogue’ is defined in a thick fashion as substantive exchange on the merits of constitutional questions, there may be no country capable of satisfying the definition. The case of Canada, often held up as the leading example of judicial dialogue, illustrates the severe definitional challenges surrounding the concept.