Acquired Rights in International Administrative Law

Until recently, there has been a basic consensus on the understanding of the acquired rights doctrine which is said to constitute a supreme general principle of international civil service law, also known as international administrative law. In this paper, I show that this consensus painstakingly developed over decades by international administrative tribunals has now been broken. I chart the history of the doctrine showing how it was initially received to perform a protective function given the considerably weaker position of the employee vis-à-vis the employer organization. Primarily through the jurisprudence of the Administrative Tribunal of the International Labor Organization (‘ILOAT’), the doctrine’s conventional understanding in international administrative law was then developed and refined over several decades. However, in its recent jurisprudence, the United Nations Appeals Tribunal has rendered the acquired rights doctrine with little work to do by collapsing it to the principle of non-retroactivity. The consensus as to the doctrine’s meaning is now undermined. This is an unwelcome development.