Israel's Strike on Iran Under International Law
In recent days, numerous scholars in the field of international law have presented opinions, sprouting like mushrooms after rain, claiming that Israel's attack on Iran's nuclear facilities and strategic infrastructure does not meet the requirements of international law, particularly the laws governing the use of force (jus ad bellum). According to their claims, this constitutes an illegal use of force, which in their view can only be justified through a very expansive interpretation of preemptive self-defense (which is not accepted in the literature and jurisprudence in this field).
However, these analyses rely on only a partial factual foundation and apply a narrow interpretation of international law, while ignoring essential contexts and the evolution of customary law over the years.
To assess the legality of Israel's action, four main components must be addressed:
Iran attacked Israel directly twice: on April 2024 and October 2024.
The Caroline Doctrine, recognized as binding law in customary law since the 19th century, permits immediate action in situations of grave and imminent threat.
Israel did not initiate a preventive war, but rather acted in response to acts of ongoing aggression and a tactical window of opportunity that was closing.
The issue of the targeted objectives, particularly regarding the scientists, is somewhat more complex but does not necessarily constitute a violation of the laws of war.
In Detail:
1. Iran attacked Israel directly twice, constituting a clear armed conflict
On April 13, 2024, Iran launched hundreds of missiles and UAVs from its territory toward cities and security infrastructure in Israel. This was a direct, overt attack by one sovereign state against another, conducted without the mediation of proxy or surrogate organizations [which are also punishable under international law and may constitute grounds for counter-military action, see: Nicaragua v. United States (ICJ, 1986)]
On October 1, 2024 of the same year, Iran attacked again, this time focusing on additional critical infrastructure within Israeli territory. This attack was also carried out directly from Iranian territory, without the involvement of external organizations.
Both attacks clearly constitute an "armed attack" under Article 51 of the UN Charter, which grants the attacked state the right to exercise defensive force. International law does not require an immediate real-time response, nor does any law impose a specific time limit on military response, especially when dealing with such a measured, strategic, and calculated operation, and particularly when it involves an ongoing conflict that includes cumulative threats and dangerous infrastructure such as nuclear weapons.
2. The Caroline Doctrine permits immediate action when the threat is immediate and grave
The doctrine that developed following the Caroline vessel crisis in 1837, and has since been recognized as an integral part of binding customary law, establishes that preemptive force may be used when the following three conditions are met:
a. The threat is immediate, tangible, and undeniable
b. No effective political or diplomatic alternative exists
c. There is no time for normal decision-making processes
Israel can rightfully claim that the situation vis-à-vis Iran meets all three criteria. Iran stands on the verge of a nuclear technological breakthrough; the diplomatic track has failed and is accompanied by repeated declarations to destroy Israel, while Iran continues developing launch capabilities and deploying long-range weapon systems. Once Iran crosses the nuclear threshold, any future action may become impossible or too dangerous. Therefore, the Israeli action clearly fits within this framework.
3. Not a preemptive preventive war, but rather the exercise of ongoing self-defense rights
A crucial distinction must be made between preventive war, which aims to neutralize a hypothetical future threat, and action within the framework of self-defense that responds to a real, substantiated, and ongoing threat. Israel did not attack Iran based solely on intelligence assessments, but after having already absorbed two direct attacks from the Iranian state. These attacks are in addition to numerous strikes from proxy organizations that Iran has been training and funding for years.
In this context, the principles of proportionality and necessity must be examined. Military action is considered legally justified if it is required to neutralize the threat, and if the force, scope, and benefit inherent in it match the severity of the danger.
Proportionality in self-defense does not require symmetry, nor does it require waiting until a strike is completed. It means the response must be necessary to neutralize the threat, and proportional to the danger posed.
Attacking military installations and nuclear development centers, at a time when intelligence indicates a narrow window of action, meets this test.
4. The status of nuclear scientists depends on circumstances and does not necessarily afford them protection as civilians under the Fourth Geneva Convention and Additional Protocol I
International humanitarian law prohibits the deliberate targeting of civilians, except in cases where they directly participate in hostilities. If the scientists operate within a clear military framework, for example as part of the IRGC, they are considered legitimate military targets. Even if they are not uniformed soldiers, their work may play a vital role in developing unconventional weapons in a manner that justifies classifying them as direct participants in hostilities, just as a getaway driver during a bank robbery is considered a full accomplice to the crime, even without personally executing the robbery or carrying a weapon.
The facilities themselves, such as enrichment reactors, command centers, and control systems, undoubtedly constitute military targets in accordance with the laws of war. Therefore, the claim that this constitutes a violation of humanitarian law lacks legal foundation.
Final Thoughts
All expert opinions regarding the illegality of the Israeli action should be examined with great caution, and one should not accept at face value the apparent authority of these 'thinkers' and 'experts.' The claim that Israel committed unlawful aggression ignores both the facts and legal precedent, and it is difficult to overlook the politics behind a determination so disconnected from the background and reality on the ground.
If one accepts the fact that Iran attacked Israel directly twice in less than a year, while simultaneously advancing toward nuclear capability with declared intentions to destroy the State of Israel, it is difficult to see how one can claim that Israel's action fails to meet the requirements of international law.
To insist that a state must absorb a nuclear attack before it can act is a legal, moral, and strategic absurdity. Israel exercised its right to self-defense under extreme conditions, against an enemy that has violated every limitation of restraint, and there is no deviation from the normative framework of existing legal principles in this action.
References
United Nations Charter (1945), Article 51 - Right of Self-Defense
https://www.un.org/en/about-us/un-charter/chapter-7Letter from Daniel Webster to Lord Ashburton (1842) - The Caroline Doctrine
https://avalon.law.yale.edu/19th_century/br-1842d.aspInternational Court of Justice, Nicaragua v. United States (1986) - Principles of Self-Defense
https://www.icj-cij.org/case/70International Court of Justice, Nuclear Weapons Advisory Opinion (1996) - Legality of Threat or Use of Nuclear Weapons
https://www.icj-cij.org/case/95Geneva Convention IV (1949) and Additional Protocol I (1977) - Protection of Civilians in Armed Conflict
https://ihl-databases.icrc.org/en/ihl-treaties/gciv-1949
https://ihl-databases.icrc.org/en/ihl-treaties/api-1977Dinstein, Y. (2017). War, Aggression and Self-Defence (6th ed.). Cambridge University Press.
https://www.cambridge.org/core_title/gb/419391Schmitt, M. N. (2003). "Preemptive Strategies in International Law." Michigan Journal of International Law, 24, 513-548.
https://repository.law.umich.edu/mjil/vol24/iss2/3/International Committee of the Red Cross (2009). Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law.
https://www.icrc.org/en/doc/assets/files/other/icrc-002-0990.pdfUN Security Council Resolutions on Iran's Nuclear Program (2006-2015) - Resolutions 1696, 1737, 1747, 1803, 1835, 1929, 2231.
https://www.un.org/securitycouncil/content/resolutionsInternational Atomic Energy Agency Reports on Iran's Nuclear Program (2011-2024) - Quarterly Reports to the Board of Governors.
https://www.iaea.org/newscenter/focus/iranNicaragua v. United States (ICJ, 1986).
I think this can appear a less one-sided defense if the reason for Iran's strikes were contextualised : surgical strikes and assassination of proxy leadership. Perhaps, adding legal arguments to justify that move and expose the grim realities of the Iranian regime will be a better counter?