World Court Issues Advisory Opinion Endorsing Professor Koh’s Position Favoring an International Right to Strike
By a vote of 10-4. the International Court of Justice (ICJ) in the Hague issued a historic advisory opinion finding that the right of workers to strike is encompassed in the “freedom of association” protected by the 1948 International Labor Convention No. 87, concerning Freedom of Association and Protection of the Right to Organize. In so ruling, the Court, speaking through its President Yuji Iwasawa, largely followed arguments presented in October 2025 by Harold Hongju Koh, Sterling Professor of International Law, and his co-counsel on behalf of the International Trade Union Confederation (ITUC) — the world’s most representative international workers’ organization. In addition to Koh, the ITUC — which speaks for 191 million workers across 169 countries — was represented before the ICJ by a legal team that included general counsel of the ITUC Paapa Danquah and international law professors Pierre Klein of Brussels, Philippe Sands of University College London, and Phoebe Okowa of Queen Mary University, University of London (who was subsequently elected as a judge of the ICJ and was recused from the Court’s advisory opinion).
Watch the argument (Koh begins at 1:50:45) and read about it.
The ICJ is the United Nations’ highest court, established in June 1945 by the Charter of the United Nations and seated at the Peace Palace in The Hague (Netherlands). The Court has jurisdiction both to resolve contentious disputes between member nations and to deliver advisory opinions to answer questions referred to it by the United Nations or specialized international agencies.
In this case, the Court was asked by the ILO Governing Body to render an advisory opinion on the question whether the right to strike of workers and their organizations is protected under Convention No. 87. Adopted after World War II, Convention 87 is a cornerstone of international labor law, guaranteeing workers and employers the right to form and join organizations of their choosing. Although Convention 87 does not explicitly mention a right to strike, the Court’s opinion answered the advisory question in the affirmative, interpreting the freedom of association protected by the Convention to include the right to strike.
The majority ruled that “freedom of association is instrumental in facilitating workers’ organizations to take collective action to further and defend the interests of their members, including through the exercise of the right to strike. … [S]trike action is one of the main activities engaged in and tools used by workers and their organizations to promote their interests and improve conditions of labour, thereby ensuring the effective exercise of the freedom of association protected under Convention No. 87.” Judge Sarah Cleveland ’92 joined the Court’s opinion and added in a separate declaration that workers “associate to try to enhance their collective power in order to secure better wages, hours, and working conditions. While ordinarily an instrument of last resort, a strike is a vital tool for protecting workers from exploitation and defending human dignity in the workplace. Without the right to strike, employees lose the leverage needed to overcome power asymmetry in the workplace and at the bargaining table, so employers no longer need to negotiate in good faith.”
Koh had similarly told the Court at the October hearing that legal recognition of the right to strike would not threaten social order. “In real life,” he observed, “the right to strike is a safety valve, a nonviolent bulwark of social peace. Every day, we are served meals and drinks, ride in cars and buses, and work in offices on equipment that is built, prepared, and maintained by committed and conscientious workers. They don’t want to strike; they want to work; to do their jobs for a fair and honest wage. But behind their toil is constant awareness that if their rights are abused, they hold the fundamental right to withhold that work in fellowship with their co-workers.”
Cleveland further suggested that, while the Court did not reach the question, “given the breadth of recognition of the right to strike in numerous overlapping international and regional instruments — as well as in at least 97 States and its legislative protection in more than 150 others — a compelling case can be made that protection of the right to strike is a principle of customary international law.” Professor James Brudney ’79 of Fordham Law School, who long served as a member of the ILO’s Committee of Experts, made a similar argument in a 2021 Yale Journal of International Law article.
Koh called the decision a “landmark ruling. The Court’s position will affect the real rights of tens of millions of working people around the world. The Court’s judgment strengthens industrial democracy and reaffirms a global norm endorsing peaceful bargaining between employers and workers the world over. The Court’s decisive opinion could lead to changes in labor laws worldwide in countries that thus far have not recognized employees' right to strike.”
Koh is Sterling Professor of International Law at Yale Law School, where he has taught since 1985, served as dean from 2004 to 2009, and currently co-directs the Peter Gruber Rule of Law Clinic. He is one of the nation’s leading experts in public and private international law, national security law, and human rights. He has served four presidents of both political parties in the Justice and State Departments. From 1998 to 2001 he served as Assistant Secretary of State for Democracy, Human Rights, and Labor, and from 2009 to 2013, he served as the 22nd Legal Adviser of the U.S. Department of State in the Obama administration. He is the author of many books and articles, most recently, “The National Security Constitution in the 21st Century” (Yale University Press, 2024) and “The Trump Administration and International Law” (Oxford University Press forthcoming rev. ed. 2027). In working on the case, Koh was assisted by Yale Law students Soledad Slowing-Romero ’25 and Trinh Truong ’27.
