TEHRAN - If states were free to attack one another based on their own assessments of possible future threats, what would be left of the international legal order? This question goes well beyond the political dispute between Iran and the United States. It concerns one of the fundamental principles on which the international order established after the Second World War rests: the use of force is governed by law, and no state, however powerful, is entitled to place its own judgment above binding rules of international law.
The military attacks launched by the United States and the Zionist regime against Iran constitute a clear violation of the prohibition on the use of force and an infringement of Iran's sovereignty. Their legality must be assessed against the U.N. Charter and established principles of international law, not against political arguments or justifications advanced after military operations have begun.
The U.N. Charter sets clear limits on the use of force
Article 2(4) of the U.N. Charter prohibits the threat or use of force against the territorial integrity or political independence of any state. This prohibition is not merely a treaty obligation. It is also a fundamental rule of customary international law, as the International Court of Justice confirmed in its 1986 judgment in the Nicaragua case.
International law permits the use of force only in narrowly defined circumstances, including the exercise of the right of self-defense under Article 51 of the Charter. The U.S. military attack on Iran had no authorization from the Security Council, nor can allegations of possible future threats, in themselves, provide a sufficient legal basis for invoking self-defense. Article 51 recognizes the right of self-defense in the event of an armed attack. To treat a potential future threat as grounds for military action would be to accept preventive war based on the unilateral judgment of individual states. Such an interpretation would seriously undermine, if not altogether empty, the prohibition on the use of force of its practical meaning.
The legality of the U.S. attack has also been challenged within the American legal community. In a statement issued on March 6, 2026, the president of the American Branch of the International Law Association described the attack on Iran as unlawful, stressing that speculative threats concerning what might happen in the future cannot justify the use of military force.
The attacks on schools, sports stadiums, civilian infrastructure, and Iranian nuclear facilities subject to International Atomic Energy Agency safeguards raise further questions under international law. Apart from the prohibition on the use of force, these attacks must also be examined in light of the rules of international humanitarian law. Parties to an armed conflict are required to distinguish between military targets and civilians, refrain from disproportionate attacks, and take all feasible precautions to minimize harm to civilians and civilian infrastructure.
Military aggression carries international legal responsibility
U.N. General Assembly Resolution 3314, which sets out the Definition of Aggression, identifies acts such as attacks by one state's armed forces against the territory of another and the blockade of a state's ports or coasts as acts of aggression. In the absence of a valid legal justification for the use of force, the U.S. military attack on Iran constitutes an internationally wrongful act for which the United States bears responsibility.
Under the law of state responsibility, a state incurs international responsibility when conduct attributable to it breaches an international obligation. That responsibility entails specific legal consequences: the state must cease the wrongful conduct if it is continuing, offer appropriate assurances and guarantees that it will not be repeated, and make full reparation for the injury caused. Political or security considerations cannot, by themselves, relieve the United States of the legal consequences of its actions.
Serious breaches of obligations arising under peremptory norms of international law, or jus cogens, also have implications for other states. International law requires states to cooperate through lawful means to bring such breaches to an end, refrain from recognizing as lawful situations created by them, and withhold aid or assistance that would help maintain those situations.
Iran, for its part, retains the right of self-defense under Article 51 of the U.N. Charter in response to an armed attack. It may exercise that right subject to the conditions and limitations imposed by international law.
This is about more than Iran
The significance of this case extends far beyond Iran's security or the balance of power in the Middle East. What is ultimately at stake is the credibility of an international legal order designed to prevent states from resorting to force at will. If military strength is allowed to take precedence over legal obligations, and states responsible for aggression can escape accountability, no country's security can be taken for granted.
The prohibition on the use of force is not a concession that powerful states make to weaker ones. It is a binding obligation that applies equally to all states. Ending U.S. aggression, respecting Iran's sovereignty and territorial integrity, and providing reparation for the damage caused by unlawful military action are matters of legal obligation, not political goodwill.
If power is permitted to prevail over law, Iran will not be the only casualty. The foundations of the international legal order, and the authority of the U.N. Charter itself, will also be at risk.
Abbas Araghchi has served as Iran's foreign minister since August 2024. Born in 1962 in Tehran, he holds a doctorate in political thought from the University of Kent in Britain and has extensive experience in diplomacy, including serving as chief nuclear negotiator with world powers. As ambassador to Japan from 2008 to 2011, he contributed to developing bilateral ties.
