Armed Conflict Foreign Relations & International Law

U.S. Submits Article 51 Letter on ‘Operation Epic Fury’ to UNSC

Tyler McBrien
Tuesday, March 17, 2026, 5:10 PM

The letter claims the United States attacked Iran as a matter of “self-defense” and the “collective self-defense” of Israel. 

On March 10, the U.S. Representative to the United Nations Ambassador Mike Waltz submitted a letter to the United Nations Security Council laying out its international legal justification for launching Operation Epic Fury. The letter describes the joint U.S.-Israeli attacks on Iran that began on Feb. 28 as “necessary and proportionate actions in exercise of the inherent right of self-defense as reflected in Article 51 of the Charter of the United Nations.”

In the Article 51 letter, the United States presents several arguments to justify its “combat operations” in Iran, which it notes “are also being conducted in close cooperation with, and in the collective self-defense of, Israel.” The letter describes the situation between the United States, Iran, and Israel as an “international armed conflict” in which Iran is “waging an unprovoked religious war of annihilation against a once-friendly United Nations Member State located hundreds of miles distant from its borders.”

The letter also alleges that “the Iranian regime routinely seeks to conceal its unlawful acts and to shield itself from accountability by, among other things, deploying proxies such as Hamas, Hizballah and the Houthis.”

For more analysis on the Trump administration’s legal justifications for its attack on Iran, read Lawfare Senior Editor Scott R. Anderson’s March 3 piece in Lawfare.

And read the U.S. Article 51 letter to the United Nations Security Council here or below:      


Tyler McBrien is the managing editor of Lawfare. He previously worked as an editor with the Council on Foreign Relations and a Princeton in Africa Fellow with Equal Education in South Africa, and holds an MA in international relations from the University of Chicago.
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