[Jessica Dorsey is an Assistant Professor of International Law at Utrecht University School of Law, an Executive Board Member of Airwars, and the Managing Editor of Opinio Juris.] In a New York Times essay published last week, Jeh Johnson, General Counsel of the Department of Defense in President Barack Obama’s first term and Director of Homeland Security in his second, seeks...
[Winona Xu teaches international law and reproductive health at UCLA] Introduction As of September 15, 2025, eight weeks after Israel’s Operation Rising Lion (June 13) and the U.S. companion strikes (Operation Midnight Hammer, June 21–22) on Fordow, Natanz, and Isfahan, the immediate legal question has fused with an acute non‑proliferation and nuclear‑safety crisis. The IAEA still cannot verify the fate of Iran’s...
[Dr Sergey Sayapin is Professor of Law at KIMEP University (Almaty, Kazakhstan)] More than eighty years after the adoption of the Charter of the United Nations, the legal framework governing the use of force by States remains plagued by ambiguity. While Article 2(4) of the Charter lays down a general prohibition on the threat or use of force, and Articles 39...
[Ananya Bhargava (she/her) is a law student at Jindal Global Law School] Introduction Historically in situations of war, international law has maintained fidelity to a strictly parochial understanding of what constitutes “use of force.” This understanding adheres to the normative belief that “use of force” solely includes armed force. Any deviation from this belief would invariably lead to the unsettling of definite...
[Masoud Zamani is a lecturer in International Law and International Relations at the University of British Columbia, Canada. Amir Abbas Kiani is a collaborating researcher in International Law at Shiraz University, Iran.] The recurring exchange of lethal force and military operations between Iran and Israel gives rise to several urgent and complex legal questions within the framework of jus ad bellum. A particularly intriguing...
On June 25, the Secretary General of the Council of Europe (CoE) and the President of Ukraine signed an agreement to create a Special Tribunal for the Crime of Aggression Against Ukraine (STCoA). The tribunal, which will be based on Ukraine's territorial jurisdiction but will have a number of international elements -- and is thus properly categorised as a hybrid...
Much has already been written about the legality of Israel and the US's attacks on Iran's nuclear facilities -- Operation Rising Lion and Operation Midnight Hammer -- including excellent critiques by Marko Milanovic (here and here) and Adil Haque (here). I don't want to rehash their arguments, with which I entirely agree. Instead, I want to explain in this post...
On April 4, a group of five states -- Costa Rica, Germany, Sierra Leone, Slovenia and Vanuatu -- formally submitted to the UN Secretary-General the text of a proposed amendment to the Rome Statute. The amendment seeks to harmonise the ICC's jurisdiction over the crime of aggression with the jurisdictional regime that applies to the other crimes. It would do...
[Captain Peter S. Konchak is a Judge Advocate in the United States Army who is currently assigned to the Office of the Staff Judge Advocate for III Armored Corps and Fort Cavazos, and whose academic work is focused on matters of national security law and policy] The views expressed in this article are those of the author and do not represent...
[Captain Peter S. Konchak is a Judge Advocate in the United States Army who is currently assigned to the Office of the Staff Judge Advocate for III Armored Corps and Fort Cavazos, and whose academic work is focused on matters of national security law and policy] The views expressed in this article are those of the author and do not represent...
[Jens Iverson is an Assistant Professor at Leiden University and a Visiting Professor/Lecturer at Vermont Law School, Santa Clara University School of Law, and University of California College of the Law, San Francisco] A previous post on Opinio Juris, Threats of Force and Attribution: The Case of Incoming Heads of State, casts doubt on the legal seriousness of Trump’s statements before...
[Dr Eitan Diamond serves as Manager and Senior Legal Expert at the Diakonia IHL Centre in Jerusalem. Dr Ellen Nohle serves as a Senior Legal Advisor and Legal Team Coordinator at the Diakonia IHL Centre in Jerusalem. Anna-Christina Schmidl serves as a Legal Advisor at the Diakonia IHL Centre in Jerusalem.] Introduction Between 7 October 2023, when hostilities broke out in Israel and Gaza,...