Jus Cogens and Erga Omnes Obligations in the United States–Israel and Iran Conflict: An International Law Perspective

Abstract

Abstract

The conflict involving the United States and Israel against Iran in 2026 has raised various issues under international law, particularly concerning alleged violations of jus cogens norms and the emergence of erga omnes obligations. Military operations conducted by the United States and Israel against Iranian territory, including alleged attacks on civilian facilities, have generated significant legal questions regarding the legality of the use of armed force under international law. This study aims to analyze whether the actions of the United States and Israel may be classified as violations of jus cogens norms and to examine the relationship between such violations and the emergence of erga omnes obligations within the context of the conflict. The research employs a normative legal research method using both a conceptual approach and a statutory approach. The legal materials consist of primary, secondary, and tertiary sources, which are analyzed qualitatively through a descriptive-analytical method. The findings indicate that the alleged use of armed force without a valid legal basis may constitute a violation of the prohibition of aggression, which is recognized as a jus cogens norm in international law. Such a violation subsequently gives rise to erga omnes obligations, granting the international community both the right and the responsibility to respond to the breach in order to maintain international peace, security, and the international legal order. Therefore, the conflict involving the United States and Israel against Iran should not be regarded merely as a bilateral dispute between states, but rather as a matter affecting the fundamental interests of the international community as a whole.