by TOM DANNENBAUM, REBECCA HAMILTON, ADIL AHMAD HAQUE, OONA A. HATHAWAY, & GABOR RANA
The United States and Israel initiated strikes on Iran over one month ago, on February 28, 2026. The attack was a clear violation of the United Nations Charter. The conduct of the war, and statements of U.S. officials, also raise serious concerns about violations of international humanitarian law, including potential war crimes. We have written the below statement together with over 100 U.S.-based international law experts, to detail our profound concerns about the war. The letter is signed by international law experts across the United States, including senior professors; leaders of prominent international law associations, non-governmental organizations, and legal clinics; former government legal advisors; and military law experts and former Judge Advocates General (JAGs).
Letter of over 100 international law experts on Iran war
We, the undersigned U.S.-based international law experts, professors, and practitioners write to express profound concern about serious violations of international law and alarming rhetoric by the United States, Israel, and Iran in the present armed conflict in the Middle East.
Due to our connection to the United States, our focus here is on the conduct of the U.S. government, but we remain concerned about the risk of atrocities across the region including the continuing risks posed by the Iranian government to Iranians through violent crackdowns on dissent, and to civilians across the Middle East through Iran’s ongoing unlawful strikes on civilian infrastructure using explosive weapons in densely populated areas.
One month has passed since the United States and Israel launched strikes across Iran. The initiation of the campaign was a clear violation of the United Nations Charter, and the conduct of United States forces since, as well as statements made by senior government officials, raise serious concerns about violations of international human rights law and international humanitarian law, including potential war crimes.
We collectively affirm the importance of equal application of international law to all, including countries that hold themselves out as global leaders. Recent statements from senior U.S. government officials describing the rules governing military engagement as “stupid” and prioritizing “lethality” over “legality” are profoundly alarming and dangerously short-sighted. These claims, particularly in combination with the observable conduct of U.S. forces, are harming the international legal order and the system of international law that we have devoted our lives to promoting.
The war, which is costing U.S. taxpayers between $1-2 billion each day, is imposing significant harm to civilians in the region, has resulted in the loss of hundreds of civilian lives across the Middle East, and is causing serious environmental and economic harms.
We write to express our concern about 1) jus ad bellum, or the decision to go to war, 2) jus in bello, or the conduct of hostilities, 3) rhetoric and threats from senior U.S. officials and their allies, which portend further abuses, and 4) the decimation of civilian harm mitigation structures within the U.S. government as a part of U.S. Secretary of Defense Pete Hegseth’s “gloves off” approach to warfare.
1. Jus ad bellum concerns: The strikes launched by the United States and Israel on February 28, 2026 clearly violated the United Nations Charter prohibition on the use of force. Force against another state is only permitted in self-defense against an actual or imminent armed attack or where authorized by the UN Security Council. The Security Council did not authorize the attack. Iran did not attack Israel or the United States. Despite the Trump administration’s varied and sometimes conflicting claims to the contrary, there is no evidence that Iran posed an imminent threat that could ground a self-defense claim. Many international law experts have concluded that Israel and the United States’ actions violate the UN Charter, including the President and President-elect of the American Society of International Law, and the President of the American Branch of the International Law Association; UN Secretary-General António Guterres also condemned the attacks as undermining international peace and security.
2. Concerns about violations of international humanitarian law: The laws of armed conflict constrain the conduct of hostilities of all parties to the ongoing conflict. We are concerned that these fundamental rules may have been violated, including in the context of reported strikes on civilians and civilian objects such as political leaders who have no military role, oil and gas infrastructure, including South Pars, and water desalination plants. On March 19, UN High Commissioner for Human Rights Volker Türk condemned strikes on energy infrastructure, noting their “disastrous” impacts for civilians.
We are seriously concerned about strikes that have hit schools, health facilities, and homes. The Iranian Red Crescent reports that “67,414 civilian sites have been struck, of which 498 are schools and 236 health facilities.” A report by leading civil society organizations found that at least 1,443 Iranian civilians, including 217 children, were killed by U.S. and Israeli forces between February 28 and March 23.
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