The Iran Strike and the Erosion of the Prohibition on the Use of Force

The crisis in the Middle East raises fundamental questions regarding the application and effectiveness of core norms of international law. The targeted attacks against Iran, culminating this week in the killing of Supreme Leader Ali Khamenei and senior military officials, require analysis both in terms of the legality of the use of force under the United Nations Charter and in light of the implications for international humanitarian law.

The illegality of the joint U.S.–Israeli attack on Iran

Article 2(4) of the United Nations Charter establishes a clear and non-derogable prohibition on the use of force in international relations, except in cases of self-defense or when authorized by the Security Council. In the present case, it appears evident that neither the United States nor Israel can invoke self-defense under Article 51 of the Charter. There has been no armed attack by Iran. Even assuming that self-defense encompasses the imminent threat of an armed attack justifying preventive use of force, that is not the situation here. Iran’s nuclear program remains under the supervision of the International Atomic Energy Agency (IAEA). Even if it is plausible to suspect that Iran might use its nuclear program to develop atomic weapons in the future, such suspicion does not justify unilateral military action. If the United States and Israel considered the program a threat to peace, they should have referred the matter to the Security Council under Chapter VII of the United Nations Charter.

The joint attack on Iran therefore constitutes a manifest violation of jus ad bellum and further undermines the resilience and credibility of international legal norms.

The killing of Iranian leaders in light of international humanitarian law

The recent attacks against Iranian leaders, including Supreme Leader Ali Khamenei and other senior officials, raise additional issues under international humanitarian law (jus in bello). Under the rules of international humanitarian law, state leaders may be lawfully targeted if they qualify as combatants or, as civilians, if they directly participate in hostilities. However—and this must be emphasized—even if the position of Iranian leaders could be characterized in this way, this would not justify the joint U.S.–Israeli attack on Iran, which remains a clear violation of the prohibition on the use of force.

Khamenei’s case warrants particular consideration due to its complexity. Although his role as Commander-in-Chief of the Iranian armed forces could qualify him as a legitimate military objective under humanitarian law, the initiation of hostilities through an unlawful preventive attack raises doubts about the applicability of the principle of distinction—which requires parties to distinguish at all times between civilians and combatants, and between civilian and military objectives, prohibiting attacks against persons or objects not directly involved in hostilities—and about the temporal dimension of direct participation in hostilities. The same reasoning applies to Defense Minister Aziz Nasirzadeh and other officials, whose qualification as legitimate targets depends on their function and operational involvement, and thus on the application of jus in bello norms.

Conclusions

The attack on Iran by the United States and Israel not only violates a basic norm of contemporary international law but also further destabilizes a region already marked by conflict and tension. The justification of the intervention as a measure to prevent a future Iranian nuclear threat is weak both factually and legally. As noted, the IAEA has provided no evidence of an imminent Iranian offensive nuclear capability, and the use of force cannot be justified for the purpose of pursuing regime change—an objective explicitly declared by the U.S. administration. The responsibility of the Iranian theocratic regime for repeated violations of human rights norms does not alter this assessment.

The joint military operation against Iran sets a new and dangerous precedent of illegitimate use of force justified by openly political reasons, further eroding the collective security system established by the United Nations Charter. The implicit legitimization of preventive attacks based on perceived threats risks breaking a restraint which, however fragile and already breached in the past, has thus far largely persisted at least as a taboo against arbitrary uses of force. This could open the way to a spiral of widespread conflicts in which force prevails over law, emptied of its regulatory function. The result would be an era of “permanent war,” where the only remaining hope would be that conflicts remain as contained as possible.