Targeted Assassinations of Iranian Nuclear Scientists in Israeli Attacks Against Iran (June 2025) A Study within the Framework of Customary International Humanitarian Law.

The targeted assassinations of Iranian nuclear scientists in Israeli attacks against Iran in June 2025, as an emerging phenomenon in international relations, have created profound legal challenges in the interpretation and application of the customary rules of International Humanitarian Law (IHL). Given the gaps in international judicial practice and the destructive effects of such actions on the stability of the international legal system, this research provides a comprehensive examination of this issue.

The primary objective of this article is to conduct a holistic analysis of the assassination of Iranian nuclear scientists within the framework of the customary international legal system, focusing on two fundamental pillars: the principle of distinction between military and civilian objects and the principle of separation .

Utilizing a descriptive-analytical research method and relying on authoritative legal sources—including 1) the jurisprudence of international judicial bodies (International Court of Justice, International Criminal Court , 2) authoritative legal doctrines, 3) documents from international organizations, and 4) a comparative study of similar historical cases—this study concludes the following:

Based on customary international law derived from judicial practice, nuclear scientists, in the absence of direct and active participation in military operations, enjoy full protection as civilians. Their targeted assassination, without adherence to the principles of distinction and separation, constitutes a gross violation of peremptory norms (jus cogens) of international law . International jurisprudence demonstrates that such acts entail international criminal and civil responsibility for the perpetrators and their sponsors.

Based on the findings, this article concludes that the assassination of Iranian nuclear scientists, as an extrajudicial act falling outside the framework of customary international law, poses a serious threat to the international legal order and collective security . Emphasizing the need to strengthen international monitoring mechanisms, this study proposes that international bodies adopt practical measures, utilizing their authority, to prevent the recurrence of such incidents.



Introduction



The events of June 2025 represent an unprecedented turning point in the history of regional conflicts and the application of International Humanitarian Law (IHL). In this coordinated operation, carried out over several days in various cities across Iran, a number of Iran's most prominent nuclear scientists and engineers were targeted and assassinated using sophisticated methods. The Israeli government not only claimed responsibility for this action but explicitly declared it a necessary step in its "extraterritorial deterrence strategy" to neutralize what it termed the "existential threat of Iran's military nuclear program." This event, carried out by Israel in the June 2025 operations, has created unprecedented legal challenges in the interpretation of the fundamental principles of IHL. This action, justified by invoking the concept of direct participation in hostilities, challenges the boundaries of civilian protection in armed conflicts.



The aim of this article is to provide a precise and structured legal analysis of this event in light of existing IHL rules. The article answers the central research question: "Is the targeted assassination of Iranian nuclear scientists in the June 2025 operation compatible with the fundamental principles of humanitarian law and the law of armed conflict, including the principle of distinction between military and civilian objectives, the principle of separation, and the principle of proportionality, as defined in treaties and customary law "



Research Problem



The significance of this research can be assessed at both theoretical and practical levels. Theoretically, this analysis contributes to clarifying and potentially redefining the boundaries of the concept of direct participation in hostilities in the era of complex, technology-driven warfare. Practically, its findings can provide a basis for strengthening accountability and deterrence mechanisms within the international system, including revitalizing the role of judicial bodies such as the International Criminal Court (ICC), implementing targeted sanctions, or strengthening universal jurisdiction, thereby preventing the normalization and repetition of such actions in the future.



Methodology

This article employs a descriptive-analytical method, examining the subject by relying on authoritative legal sources including international jurisprudence, legal doctrines, and documents from international organizations.



Key Findings

From the perspective of international law, the targeted assassination of Iranian nuclear scientists in the June 2025 operation goes beyond a conventional violation; it signifies a deeper structural challenge to the entire legal system governing armed conflicts. At the heart of this challenge lies a fundamental conflict between a broad, unilateral interpretation of "preventive security necessity" on one hand, and the multilateral, rule-based framework of humanitarian law on the other. This action systematically and simultaneously violates the fundamental peremptory norms (jus cogens) of humanitarian law.



Contribution to the Field



This research demonstrates that the assassination of Iranian nuclear scientists is not only a gross violation of IHL but also a serious threat to the stability of the international system. As emphasized by international law scholars, "the development of international law in this field must strike a balance between national security and the protection of civilians."



Implications and Applications



According to this research, an effective, decisive, and multilateral legal response—encompassing judicial, monitoring, and political mechanisms—is not a choice but a vital necessity for preserving the credibility and efficacy of the international legal system itself in the face of the complex security challenges of the twenty-first century. Silence or inability in this regard means encouraging the rule of might over right and threatening the foundations of a rule-based order.



Conclusion



Based on this article, it is concluded that the assassination of Iranian nuclear scientists is not only a gross violation of IHL but also a serious threat to the stability of the international system. From the perspective of international law, the targeted assassination of Iranian nuclear scientists in the June 2025 operation goes beyond a conventional violation; it signifies a deeper structural challenge to the entire legal system governing humanitarian law and the law of armed conflict. At the heart of this challenge lies a fundamental conflict between a broad, unilateral interpretation of "preventive security necessity" on one hand, and the multilateral, rule-based framework of humanitarian law on the other.



Keywords



Customary International Law, Principle of Distinction, Targeted Killing, Nuclear Scientists, Military Necessity, Proportionality, International Responsibility, Law of Armed Conflict, Jus Cogens (Peremptory Norms).