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This is a major breaking event happening right now. Here’s what’s known and what international law says about it:
What’s Happening
The US and Israel launched a massive joint attack on Iran today (February 28, 2026). Iran’s Supreme Leader Ayatollah Ali Khamenei has been confirmed killed. Trump indicated the operation is aimed at overturning Tehran’s government, and said strikes will continue. Iran has launched widespread retaliatory strikes on US military bases, Israel, and other targets across the Middle East. (CNN)
Is the Attack a Violation of International Law?
This is genuinely contested, but most international law scholars would say yes, it likely is, for the following reasons:
The case that it IS a violation:
The UN Charter (Article 2(4)) prohibits the use of force against the territorial integrity of another state. The two recognized exceptions are: (1) UN Security Council authorization, and (2) self-defense under Article 51.
At the UN Security Council meeting, US Ambassador Mike Waltz justified the strikes by citing a broad catalog of Iranian aggression over many years, but notably did not point to any imminent threat posed by Iran (CNN) — which is the standard required for a self-defense claim under international law. Accumulated grievances and future hypothetical threats (like a nuclear program) generally do not meet that threshold without imminence.
A stated goal of regime change is not a recognized basis for the use of force under international law.
The US/Israeli argument:
Anticipatory or preventive self-defense: that Iran’s nuclear program and missile development posed a grave and mounting danger.
Accumulated acts of Iranian aggression (funding proxies, attacks on US forces, etc.) as cumulative justification.
Some legal scholars accept a broader reading of Article 51 that permits action against states actively building weapons of mass destruction.
Most mainstream international law experts would say the preventive/preemptive justification — absent an imminent attack — does not satisfy the requirements of Article 51, making the strikes a violation of the UN Charter.
Was Killing Khamenei Legal Under International Law?
This is even more legally fraught. There are two frameworks to consider:
If treated as an armed conflict (laws of war / IHL): A head of state who is also effectively the commander-in-chief of military forces can be a lawful military target under the laws of armed conflict (International Humanitarian Law), provided he was directly participating in hostilities. Khamenei, as Supreme Leader commanding the IRGC and directing proxy forces, would likely qualify as a legitimate combatant target if a lawful state of armed conflict exists between the US/Israel and Iran.
Under peacetime international law: Targeted killing of a foreign head of state is generally prohibited. The 1973 UN Convention on internationally protected persons, customary international law, and longstanding prohibitions on assassination (including the US’s own executive orders, though these have been interpreted narrowly) all weigh against it.
The core problem is circular: if the underlying attack itself is illegal, then targeting Khamenei within that illegal framework doesn’t become lawful just because he’s a military commander. Conversely, if the attack is deemed lawful armed conflict, his targeting becomes more defensible.
Bottom Line
The weight of mainstream international legal opinion will almost certainly be that the attack violates the UN Charter’s prohibition on the use of force, since no imminent threat or Security Council authorization was present. The killing of Khamenei sits in a grey area — potentially defensible as a military target under the laws of war if the conflict itself were deemed lawful, but deeply problematic given the legal basis for the strikes themselves. Expect intense debate at the UN and among international law scholars in the days ahead.