Agenda-Setters, Permission-Givers, and Gate-Keepers: A Triadic Theory of Litigation and Decision-Making by International Courts

New-style international courts operate with a dual mandate. They monitor and coordinate member state cooperation, but they also hear cases brought by non-governmental litigants. The way these courts negotiate between the input of private litigants and the constraints imposed by governments has remained under-theorized. We posit that courts and governments are inter-locked in mutual dependence in which actors' status-quo bias work in favor of the court. While governments look to the judiciary both for predictability and new policy solutions, courts are reliant on governments to render their decisions effective. By bringing cases to court, private litigants set the judicial agenda and propose legal solutions. However, we theorize that courts act as gate-keepers to supranational solutions. Borrowing from the causal language proposed for critical junctures, we consider governments' support for the applicant as a permissive condition in which a court can selectively grant wins to litigants whose claims align with the court's political agenda (a productive condition). Absent governmental permission, the court may still defend its political agenda to the extent that it aligns with the legal status quo. We draw on an original dataset of parties and lawyers involved in preliminary references before the European Court of Justice -- arguably the most influential new-style international court. We find that the Court pro-actively invites governments' input by increasing its chamber size, thus attracting new government submissions. With their permission, the Court selectively grants wins both to its core compliance constituency (individual litigants) and to parties' with quality legal arguments. Absent government permission, the Court more often conclude cases in line with previous case law than give sway to quality arguments. We conclude by highlighting the necessity to bring theories of legal mobilization closer to judicial politics for explaining litigant success and judicial agency in international settings.