In practice, national courts frequently decline to exercise jurisdiction over disputes involving international organizations either as plaintiffs or defendants, even when the international organizations are only involved peripherally, whether as third parties or as persons whose acts might be decisive for a legal dispute between other parties. Courts may decline to exercise jurisdiction for a number of reasons that could be termed ‘internal’ or ‘domestic’ in so far as their jurisprudential rationale or legal-political purpose clearly has roots within the domestic realm. Distribution of powers arguments, underlying the ‘political questions’ doctrine, rank here next to ‘case’ or ‘controversy’ requirements intended to further the efficacy of the administration of justice. Courts may, however, also use ‘international’ reasons or policy arguments that relate to the ‘external’, international relations of a forum state. The most prominent among them is, of course, the grant of immunity to international organizations which is normally perceived as a requirement under international law, conventional or customary. Certain strategies might also involve both internal and external rationales. The US-type act of state doctrine is a good example resting on internal power distribution rationales as well as on external comity considerations.

Apart from official high-level rationales to decline jurisdiction over certain disputes, domestic courts can have considerably more mundane reasons to avoid disputes involving international organizations.