Highlights of the Doctrine of Acquired Rights and the Jurisprudence of International Administrative Tribunals

This chapter outlines the major contributions of international administrative tribunals to the development of the concept of “acquired rights” in this field of law. In this regard, the solid contribution of the International Labour Organization Administrative Tribunal (ILOAT) and the Merode test developed by the World Bank Administrative Tribunal are subject to scrutiny as analytical tools to be used in similar contexts. The analysis takes into consideration the facts of each case but expands its application to different settings and factual contexts by using the concept of “fundamental term of a contract” as a defining element. This key concept establishes a distinction between which “terms of employment relationship” can be unilaterally changed by the employer (i.e. the international organisation) and those which cannot be subject to change. In contrast with the more favourable (from a staff member’s point of view) approach taken by the ILOAT, the UNAT jurisprudence is also subject to a closer look. In fact, in 2017 UNAT’s jurisprudence departed from the traditional (and more consensual) notion of acquired rights and revived an old-fashioned and narrow interpretation of “acquired rights” linking it directly to the principle of non-retroactivity. This conservative jurisprudence opened a gap in the United Nations system of benefits and entitlements and created a difference between specialised agencies (which fall under ILOAT’s jurisdiction) and the UN Secretariat, which is bound by UNAT’s decisions.