30 years of the Advisory Opinion on the Legality of Nuclear Weapons: eppur si muove

Abstract The 1996 Advisory Opinion of the International Court of Justice (ICJ) on the Legality of the Threat or Use of Nuclear Weapons remains a pivotal reference in international law and disarmament debates. While the Opinion did not categorically prohibit nuclear weapons, its reasoning has been widely cited in legal and diplomatic arenas. This study examines the Opinion’s long-term influence through three key elements: its incorporation into state practice, its role in international litigation, and its impact on the 2017 Treaty on the Prohibition of Nuclear Weapons. Employing a methodology centered on primary sources, this research evaluates the Opinion’s relevance in shaping international legal norms and assesses whether it still accurately reflects the state of international law on nuclear disarmament.