This article provides a novel and provocative framework to assess the varied authority of international courts (ICs). We generate practicable metric that assesses de facto IC authority according to a conjunctive standard — the recognition of an obligation to comply with IC rulings, and the engagement in meaningful actions that push toward giving full effect to IC rulings. We then identify five possible types of IC authority — no authority in fact, narrow, intermediate, extensive, and public authority — that correspond to the different audiences for IC rulings. The goal of this metric is to help the contributors to a symposium on ICs assess how contextual factors largely beyond the control of judges affect IC authority. We also identify three analytically distinct categories of contextual factors that influence IC authority: institution-specific context, constituencies, and geopolitics. The final section of the paper considers the relationship of IC authority to IC power. Powerful ICs have intermediate and extensive authority that extends across a broad range of issue areas and types of cases.
Three features of this framework are distinctive. First, we separate IC authority from IC legitimacy, allowing for the possibility that authoritative ICs might lack legitimacy, and legitimate ICs might lack authority as we have defined it. Second, our framework moves beyond a number of prevalent but misguided binaries, such as the idea that ICs either do or do not have authority. Third, we provide a realistic tool to grapple with the complex reality that IC authority can vary by audience, among countries, over time, and across the issue areas within an IC’s jurisdiction.