Constitutional principles are sometimes invoked in adjudication as a bridge to foreign law. This article argues that a cosmopolitan approach, such as that advocated by Jeremy Waldron through his ius gentium theory, is useful in accounting for the use of constitutional principles by courts insofar as the commonality of language and methodology surrounding the use of constitutional principles is connected to societal and institutional needs. The article argues that constitutional principles often serve as a connection to foreign law because the principles are applied as representations of a societal need for order and stability. At the same time, the article cautions that transnational judicial dialogue is impacted by compartmentalisation and divergence. Consequently, arguments for a ius gentium must be more cautious and nuanced. As a step in this direction, the article proposes two ideas for modifying the ius gentium theory: conceiving of the ius gentium as an emerging but not yet fully realised system and characterising the ius gentium as a convergence of methodology rather than substantive norms.