Frederick Schauer begins by reviewing the idea of dialogue beyond the domestic context, where it is often used to refer to the idea that the decisions of courts are subject to further modification, override, or nullification by the legislature. In the international and transnational context, the language and idea of dialogue is used to refer to the process in which constitutional courts take account of constitutional provisions and decisions in other countries. Schauer reviews two arguments often used to defend dialogue in this context. The first tracks the marketplace of ideas justification often associated with freedom of expression, according to which sound constitutional ideas will prevail over unsound ones, at least in the long run, when both become subjects of discussion and criticism. The second argument treats transnational dialogue as facilitative or constitutive of transnational cooperation, such that transnational constitutional dialogue is the vehicle for increased transnational cooperation and that such cooperation is a good in itself. Schauer’s critical review of the first argument suggests that there may be little basis for much confidence that transnational constitutional dialogue will incline towards soundness. His critical review of the second argument invites us to question what the idea of dialogue is contributing to our view of international cooperation.