Eighty years of postwar multilateralism: Global health law's emergence and its contemporary challenges.

Founded on the postwar conviction that health is 'fundamental to the attainment of peace' and that its enjoyment constitutes 'a fundamental human right', the WHO has embodied the UN's ambition to constitutionalise solidarity through law. Nearly eight decades later, this normative order faces a profound legitimacy crisis. The tension between sovereignty and universality has reemerged, and the ethical foundations of global health law are increasingly contested and fragmented. From several revisions of the International Health Regulations to the WHO Framework Convention on Tobacco Control and, most recently, the post-COVID Pandemic Agreement, the WHO's authority has been tested by populist nationalism, market logics, and the erosion of multilateralism, exposed most visibly during the US withdrawal under the Trump administration. Through a genealogical reading of the WHO as legal infrastructure, this article examines it as a postwar legal experiment in transforming international health cooperation into a form of global constitutionalism. It asks whether contemporary regressions toward security-driven governance mark a return to the prewar logic of exceptionalism. It concludes that the future legitimacy of global health law depends on a decolonial approach to what counts as 'global' and what constitutes 'health' through plural, equitable, and interdependent forms of governance for justice.