Given their catastrophic effects, nuclear weapons can never be used in conformity with the UN Charter or international humanitarian law.
Much has changed in the 30 years since the world’s highest court, the International Court of Justice (ICJ), issued its landmark advisory opinion on the legality of the use and threat of use of nuclear weapons. New conventions have been negotiated and brought into force prohibiting a wide range of activities relating to nuclear weapons, regionally and globally; the policies and practices of several nations have shifted either towards or away from reliance on nuclear weapons; and scientific knowledge of the risks and consequences of the use of nuclear weapons has deepened.
These developments were the focus of an event in New York on 28 October at Malaysia’s permanent mission to the United Nations, which reflected on the legacy of the court’s 1996 opinion. In her opening remarks, the Malaysian ambassador to the UN, Dato’ Nadzirah Osman, said that “international law has continued to evolve” over the past three decades, though the opinion remains “deeply relevant, particularly against the backdrop of heightened nuclear risks, growing geopolitical tensions, and continued challenges to the international disarmament architecture”.
While the judges of the court in 1996 were divided on the question of complete versus general illegality of use, they were unanimous in their conclusion that there “exists an obligation to pursue in good faith and bring to a conclusion negotiations leading to nuclear disarmament in all its aspects under strict and effective international control”. “[This] fundamental imperative remains unchanged,” Osman said. “Nuclear disarmament is not merely a political aspiration, but an international legal obligation that demands meaningful action.”
In addition to Malaysia, the missions of Mexico and Costa Rica co-sponsored the event, with the support of four civil society organisations: the Lex Mundi Nova initiative of Horizon 2045, the International Campaign to Abolish Nuclear Weapons (ICAN), International Physicians for the Prevention of Nuclear War, and the Lawyers Committee on Nuclear Policy. It coincided with International Law Week and Disarmament Week at the United Nations.
A global treaty-based prohibition
Speaking at the event, ICAN’s general counsel and United Nations liaison, Seth Shelden, noted that in 1996 the ICJ had “extensively analysed whether any treaty generally prohibited nuclear weapons, and found no examples. The TPNW remedies that,” he said, referring to the Treaty on the Prohibition of Nuclear Weapons, which was negotiated and adopted at the United Nations in 2017 and entered into force in 2021.
“It establishes the first treaty-based prohibition of all nuclear weapons activities, including use, threat of use, development, possession, testing, stationing, and transfer, and establishes a framework for elimination,” he said. Though no nuclear-armed state has joined it to date, 75 states are counted as parties and a further 26 as signatories, meaning that “a global majority have now taken legal commitments on a general and complete prohibition”, he added.
The other speakers – Jasmine Moussa of Egypt, Pablo Arrocha of Mexico, and Romi Brammer of South Africa – highlighted important developments in international environmental law and human rights law since 1996, and challenged the notion that the use of nuclear weapons might be lawful in extreme circumstances of self-defence. The event was moderated by Kathleen Lawand, co-director of Lex Mundi Nova, which recently organised a six-part webinar series on the same topic. “While international law cannot on its own make the use of nuclear weapons impossible, it can create taboos that make certain acts unthinkable or more difficult,” she said.
This July, in a statement marking the 30th anniversary of the advisory opinion, ICAN’s executive director, Melissa Parke, said: “As we reflect on the legacy of the court’s historic ruling, let us consider how we might make use of the international legal system in the years ahead to advance the cause of a nuclear-weapon-free world. International law matters more than ever; it must be defended and promoted as if our lives depend on it – because they do.”
