The chapter looks into how normative contestation – broadly defined as opposition by entities and persons influencing the legal discourse – may pose a limit to the influence of the analogy between States and international organizations. Those to whom the analogy is unappealing because ‘international organizations are not States!’ may proactively advocate for other visions for the public international law of international organizations, and thus be a force for change and innovation. The chapter surveys examples of normative contestation in the case of particularly controversial rules of general international law, such as the rules on immunity, self-defence, reservations, necessity and countermeasures.