US-Israeli Strikes on Iran: International Law Qualifications

On June 13, 2025, Israel struck a number of targets in Iran (fuel enrichment facilities, military sites and plants, air defense systems, missile installations, as well as oil and gas infrastructure), and eliminated several high-ranking Iranian military officials and nuclear scientists (Operation Rising Lion). In response, Iran subjected Israel to missile attacks (Operation Truthful Promise 3). On the night of June 22, the United States supported Israel by striking Iranian nuclear facilities, likely destroying them completely by using GBU-57 MOP bombs weighing 13.6 tons each. On June 24, Iran and Israel agreed to a ceasefire.

In justification of the strikes, Israel referred to the fact that the Ayatollah regime has set itself the goal of destroying Israel, spreading global and regional terror, using its proxies (Hezbollah, Hamas, and the Houthis), inciting anti-Semitism, and developing nuclear weapons. Nuclear weapons in the hands of Iran pose a clear, immediate, and existential threat to the existence of Israel and peace in the region. Israel has information that Iran planned to transfer nuclear weapons to “its terrorist proxies.” Operation Rising Lion is a measure of last resort; it was prompted by the “critical development of Iran’s secret program to create nuclear weapons and represents a response to the threat of imminent attack” and was carried out as part of the “last window of opportunity” after all available diplomatic means were exhausted. Israel believes it defends itself, as well as its Arab neighbors, Europe, and the US.

The only international legal argument that Israel can (and does) use is the right to self-defense.

Situation Peculiarity from an International Law Perspective:

First, the source of escalation is Israel—a state that has been blamed for massive human rights violations in Gaza or even genocide of the Palestinian people (its actions in Gaza have been classified as a genocide by some NGOs and by several experts in international law. In December 2023, South Africa accused Israel of violating the 1948 Genocide Convention and brought an action against it before the UN Court). The attack on Iran in this context appears to be an attempt to weaken a political opponent counteracting these violations, and domestically—an attempt to increase the legitimacy of Netanyahu’s government and to secure support for its aggressive course. US actions, in turn, appear to be complicit in committing these violations.

Second, Israel’s position is not supported by convincing legal arguments. The most relevant argument is preventive self-defense, and the closest analogy is the 2003 US invasion of Iraq. The concept of preventive self-defense, however, does not constitute a part of common law; its application to the situation under consideration implies many assumptions (if not cynicism). In addition, US actions in 2003 were justified not only by the right to self-defense, but also by SC Resolution 678, which authorized the use of force.

Third, Israel focuses on political arguments: Iran is defined as hostis generis humani; Hezbollah, Hamas, and the Houthis—as its mercenaries; nuclear weapon development is an existential threat; and Israel is the only guarantor of regional stability. Israel also highlights the threat of terrorism and anti-Semitism, Israel’s vulnerability, and the propensity of Muslim societies to violence. Many of these arguments have been tested in relation to Palestine and all of them are found to be inconsistent with international law.

Fourth, the actions of Israel and the US are reviving the narrative that some states have the right to develop nuclear weapons and use force only because they consider themselves civilized, whereas others are condemned to bear the label of rogue states and terrorist accomplices. In this sense, they have damaged not only Iran’s nuclear program, but also international law by undermining confidence in the latter's effectiveness by distorting one of its basic institutions—the right to self-defense.

His heart is as firm as a stone; Yea, as hard as a piece of the nether millstone.
When he raiseth up himself, the mighty are afraid:
By reason of breakings they purify themselves.
The sword of him that layeth at him cannot hold:
The spear, the dart, nor the habergeon.
He esteemeth iron as straw, And brass as rotten wood…
Upon earth there is not his like,
Who is made without fear.
He beholdeth all high things:
He is a king over all the children of pride.
Job 41:24-34 King James Version (KJV)
Timeline of Events

On June 13, 2025, Israel struck a number of targets in Iran (fuel enrichment facilities, military sites and plants, air defense systems, missile installations, as well as oil and gas infrastructure), and eliminated several high-ranking Iranian military officials and nuclear scientists (Operation Rising Lion). In response, Iran subjected Israel to missile attacks (Operation Truthful Promise 3). On the night of June 22, the United States supported Israel by striking Iranian nuclear facilities, likely destroying them completely by using GBU-57 MOP bombs weighing 13.6 tons each. On June 24, Iran and Israel agreed to a ceasefire.

Israel's attack was preceded by the IAEA's May 31, 2025 quarterly report, “Verification and Monitoring in the Islamic Republic of Iran in Light of Security Council Resolution 2231 (2015),” and the June 12, 2025 Resolution of the IAEA Board of Governors, which acknowledged Iran's violations of the Joint Comprehensive Plan of Action (JCPOA) and the Non-Proliferation Treaty. In addition, significant progress in the implementation of Iran’s nuclear program was noted, particularly an increased stockpile of 60% enriched uranium suitable for nuclear weapons production. According to the Resolution, “Iran's multiple failures to comply with its obligations to cooperate fully and in a timely manner with the Agency with respect to undeclared nuclear material and activities at numerous undeclared locations in Iran.... constitute as non-compliance.” Thus, “the Agency is unable to establish that there has been no diversion of nuclear material safeguarded under the Agreement to the production of nuclear weapons.”

On June 13, UN Secretary-General A. Guterres expressed “particular concern regarding the Israeli attacks while negotiations between Iran and the US over Iran’s nuclear program continue.” On June 14, the EU’s High Representative for Foreign Affairs issued a statement expressing concern about the situation, emphasizing Israel’s right to security, calling on all parties to respect international law, and stating that Iran should not acquire nuclear weapons (this statement did not include the phrase “Israel has the right to self-defense,” which 15 countries, including France, Germany, Italy, and the Netherlands, wanted to add). On June 16, the G-7 leaders made a joint statement, condemning Iran as “the main source of regional instability and terror,” emphasizing Israel’s right to self-defense. On June 22, Russia “strongly condemned” the US strikes, emphasizing that they violated international law.

In justification of the strikes, Israel referred to the fact that the Ayatollah regime has set itself the goal of destroying Israel, spreading global and regional terror, using its proxies (Hezbollah, Hamas, and the Houthis), inciting anti-Semitism, and developing nuclear weapons. Nuclear weapons in the hands of Iran pose a clear, immediate, and existential threat to the existence of Israel and peace in the region. Israel has information that Iran planned to transfer nuclear weapons to “its terrorist proxies.” Operation Rising Lion is a measure of last resort; it was prompted by the “critical development of Iran’s secret program to create nuclear weapons and represents a response to the threat of imminent attack” and was carried out as part of the “last window of opportunity” after all available diplomatic means were exhausted. Israel believes it defends itself, as well as its Arab neighbors, Europe, and the US (see the June 14 statement by Israeli President I. Herzog, the June 14 statement by Israeli Prime Minister B. Netanyahu, and the June 17 letter from Israeli Foreign Minister G. Saar to the UN Security Council).

There are no documents containing the legal justification for the June 22 strikes on the US State Department’s website. In his tweets, President Trump only reports on the success of US weaponry, threatens the Supreme Leader of Iran, and welcomes the ceasefire.

Preventive Self-Defense

The only international legal argument that Israel can (and does) use is the right to self-defense. Article 51 of the UN Charter authorizes the use of force only in self-defense only “if an armed attack occurs against a Member of the United Nations.” In other words, self-defense can only be carried out in response to an act of aggression (but not to prevent such an act). In addition to the existence of an attack, self-defense implies necessity and proportionality: it can only be exercised after all available means of settlement have been exhausted and must be limited to repelling the attack (halting and repelling).

Hugo Grotius once wrote: “Resorting to violence in order to avoid potential violence is devoid of any basis of justice. Human life is such that complete security is never guaranteed to us. For protection against uncertain fears, we should rely on divine justice and resort to ensuring security, but not to force”. [1] According to Israeli expert J. Dinstein, it is difficult to explain why the authors of the Charter regulated post-factum self-defense in detail and at the same time refused to regulate preventive self-defense, which is much more dangerous in terms of abuse. [2]

Over the past 20 years, however, the concept of self-defense has been significantly undermined by the actions of Western states in Afghanistan, Iraq, Syria and Libya. The following arguments have been developed to legitimize these actions: first, preventive self-defense is justified given the special danger of terrorist attacks and attacks using weapons of mass destruction: an adequate response to these attacks is impossible after they are carried out. Second, the State has a constitutional duty to protect its citizens, which prevails over obligations under international law. Third, the term “if” (Art. 51) does not mean “only if.” Fourth, being “inherent,” the right to self-defense cannot be restricted. Fifth, in addition to contractual grounds, there are customary legal grounds for self-defense (in other words, the customary right to self-defense exists in parallel with the right enshrined in the Charter and implies the right to preventive self-defense). Sixth, Art. 51 justifies self-defense in response to an imminent attack (a frequent example being Israel’s preemptive actions during the Six-Day War).

The classical understanding of proportionality as assuming a balance between the force used to attack and the force used in response was also blurred: according to the Israeli author D. Kretzmer, proportionality implies a relationship between means, used by a victim, and its purposes: any actions used to achieve a legitimate goal, including invasion, overthrow of the regime, occupation, are lawful. [3] All these arguments are of a marginal nature, which means that they are not supported by the majority of experts in international law. They are nevertheless part of academic discourse.

The Western Doctrine of International Law Reaction

The western doctrine of international law reacted to what has transpired by posts of M. Milanovic (UK), M. Schmitt (USA), A.A. Haque (USA) and K. J. Keller (Netherlands).

M. Milanovic, in particular, notes that the classical understanding of self-defense as allowing only post-factum actions is outdated: states have the right to prevent imminent attacks. They are not, however, entitled to warn off attacks that may occur in the future (the Bush doctrine): such an understanding of self-defense completely blurs its content. There are two approaches when defining imminence: according to the first, an imminent attack is one that is about to happen. The second refers to a situation where the aggressor has made an irrevocable decision to attack and the victim is faced with the need to use its “last window of opportunity”. Israel cannot be guided by the first approach, since Iran does not yet have nuclear weapons, thus it can only use the second approach. Iran’s anti-Israel rhetoric, however, is aimed at its domestic audience and does not imply a direct intention to use nuclear weapons against Israel (especially since Israel itself possesses nuclear weapons). There is also no talk of a “last window of opportunity” (i.e. necessity): at the time of the attack, Iran and the US were negotiating over Iran’s nuclear program. Thus, Israel’s actions violate Article 2 (4) of the UN Charter (prohibition of the use of force) and constitute aggression. The killing of scientists cannot be justified even by self-defense: scientists are not combatants and cannot be targeted.

M. Schmitt, on the contrary, justifies Israel’s actions. In his opinion, the key aspect of necessity as a self-defense criterion is “imminence.” Traditionally “imminence” was understood temporally: the victim has the right to prevent an attack just before it begins. However, after September 11, the concept of the “last window of opportunity” emerged. [4] Schmitt particularly says: “It would be absurd to assume that international law requires a state to ‘take the first blow’ when it can effectively defend itself by acting proactively. Given this premise, the correct standard for evaluating a preventive operation should be whether it was conducted in the last window of opportunity before an attack that is almost certain to occur. Simply put, it is appropriate and legitimate to use preemptive force if the potential victim must take immediate action to protect itself in an effective manner, and the potential aggressor has made a firm commitment to attack. This standard combines the component of exhausting the means of legal protection with the requirement for very high reasonable expectations of future attacks,” [5] involving three conditions: intent to attack, ability to attack, and last remaining opportunity to defend. This concept is also applicable in the present situation. First, Iran’s leaders have long threatened Israel, so Israel was entitled to consider their claims seriously. The potential victim has more leeway if the threat of error is existential. Second, it cannot be ruled out that Iran is in the process of developing a nuclear weapon as its development may be hidden and it can be carried out in a short time frame, which means Iran will become invulnerable to Israeli attacks. Thus, because of the special danger, the ability to attack must be extended to the probability of acquiring such capability. Third, Iran could have placed a nuclear weapon underground, making it invulnerable; the fact that it was negotiating does not negate its ideological and theological resolve to destroy Israel (in this connection, the “last window” can be mentioned). Thus, Israel’s actions are justified as part of a more liberal interpretation of Article 51 (as well as the actions of the US, which can be construed as the realization of the right to collective self-defense).

A.A. Haque considers the use of force by Israel to be a clear violation of the UN Charter and draws parallels with the Israeli attack on Iran’s nuclear facility in 1981, which was unanimously condemned by the Security Council (hereinafter SC) in Resolution 487. Moreover, as the IAEA has pointed out, Iran’s failure to cooperate with the Agency raises issues that fall within the purview of the SC (rather than Israel or the US). The arguments set out in Israel’s letter to the Security Council are untenable: Israel has failed to provide evidence of an imminent attack; it attacked Iran rather than the groups it supports; Israel’s actions cannot be justified by referring to Khamenei’s statements (otherwise humanity would not have survived the Cold War). Moreover, Khamenei has repeatedly stated that Iran does not intend to develop nuclear weapons whose use is contrary to Islam. Also, the actions of Iranian proxies cannot be attributed to Iran (as they are not under its direct control, as required by the 2001 Draft Articles on Responsibility of States). Israel is not facing an existential threat, but it is faced by Iran, because the former has nuclear weapons and the latter does not. Thus, the argument that Israel acted within the framework of the ongoing conflict is unacceptable; “armed conflict” implies the application of international humanitarian law rather than the right to use force, otherwise it should be admitted that Iran had also possessed the right to use force against Israel prior to June 12.

K. J. Keller argues that the concept of the “last window of opportunity” is not valid: in the absence of sufficient practice and opinio juris, it is not a legal custom. Indeed, only the United Kingdom, the United States, Australia and Israel have referred to it; the Non-Aligned Movement, consisting of 120 States, has repeatedly condemned attempts at an expanded interpretation of Article 51 of the UN Charter. [6] States may support this concept in the long run, but the problem is that it lacks a clear restrictive framework, contains a number of unclear benchmarks (such as victim immunity from possible attacks or the likelihood of nuclear weapons acquisition) and, as a result, can be used to justify any defensive act. As for Schmitt’s reference to absurdity, rationality is not a necessary condition for the existence of a rule of law: many rules of international law are absurd, but their status is not called into question. “Absurdity is the price we pay for an international order based on sovereign equality.”

Thus, all the above-mentioned authors, apart from M. Schmitt, conclude that Israel’s actions violate Article 2 (4) of the UN Charter and cannot be justified by the right to self-defense. The problem, however, is that this qualification will have no effect on the situation: it is already clear that legal mechanisms to protect Iran will not be used. Indeed, the Security Council’s reaction is unlikely: the US will surely veto a resolution condemning Israel (as it has done many times before). Hearing this case at the United Nations Court is also excluded due to the voluntary nature of its jurisdiction. The actions of Israel and the US may be condemned at the level of a General Assembly resolution, but it is doubtful that such a draft resolution will be put forward and that the resolution itself will receive a majority of votes.

Situation Peculiarity from an International Law Perspective

First, the source of escalation is Israel—a state that has been blamed for massive human rights violations in Gaza or even genocide of the Palestinian people (its actions in Gaza have been classified as a genocide by some NGOs and by several experts in international law. In December 2023, South Africa accused Israel of violating the 1948 Genocide Convention and brought an action against it before the UN Court). The attack on Iran in this context appears to be an attempt to weaken a political opponent counteracting these violations, and domestically—an attempt to increase the legitimacy of Netanyahu’s government and to secure support for its aggressive course. US actions, in turn, appear to be complicit in committing these violations.

Second, Israel’s position is not supported by convincing legal arguments. The most relevant argument is preventive self-defense, and the closest analogy is the 2003 US invasion of Iraq. The concept of preventive self-defense, however, does not constitute a part of common law; its application to the situation under consideration implies many assumptions (if not cynicism). In addition, US actions in 2003 were justified not only by the right to self-defense, but also by SC Resolution 678, which authorized the use of force. [7]

Third, Israel focuses on political arguments: Iran is defined as hostis generis humani; Hezbollah, Hamas, and the Houthis—as its mercenaries; nuclear weapon development is an existential threat; and Israel is the only guarantor of regional stability. Israel also highlights the threat of terrorism and anti-Semitism, Israel’s vulnerability, and the propensity of Muslim societies to violence. Many of these arguments have been tested in relation to Palestine and all of them are found to be inconsistent with international law.

Fourth, the actions of Israel and the US are reviving the narrative that some states have the right to develop nuclear weapons and use force only because they consider themselves civilized, whereas others are condemned to bear the label of rogue states and terrorist accomplices. In this sense, they have damaged not only Iran’s nuclear program, but also international law by undermining confidence in the latter's effectiveness by distorting one of its basic institutions—the right to self-defense.

Reference list

1. Гроций Г. Право войны и мира. М.: Ладомир, 1994. / Grotius H. The Right of War and Peace. M.: Ladomir, 1994

2. Dinstein Y. War, aggression and self-defense. CUP, 2005.

3. Greenwood Ch. The legality of the use of force: Iraq in 2003 // Bothe M. et al. (eds.) Redefining Sovereignty: the Use of Force after the Cold War. Transnational Publishers, 2005, p. 387–416.

4. Haque A.A. Indefensible: Israel’s Unlawful Attack on Iran, June 19, 2025, https://www.justsecurity.org/115010/israel-unlawful-attack-iran-charter.

5. Keller K.J. The “Last Window of Opportunity” Test Is Not the Law — and Shouldn’t Be, June 24, 2025, https://opiniojuris.org/2025/06/24/the-last-window-of-opportunity-test-is-unlawful-and-dangerous.

6. Kretzmer D. The Inherent Right to Self-Defense and Proportionality in Jus Ad Bellum // European Journal of International Law. 2013. Vol. 24. #1, p. 235–282.

7. Milanovic M. Is Israel’s Use of Force against Iran Justified by Self-Defense? June 13, 2025, https://www.ejiltalk.org/is-israels-use-of-force-against-iran-justified-by-self-defence

8. Nolte G. Multipurpose Self-Defense, Proportionality Disoriented: A Response to David Kretzmer // European Journal of International Law. 2013. Vol. 24. #1, p. 283–290.

9. Schmitt M.N. Preemptive Strategies in International Law // Michigan Journal of International Law. 2003. Vol. 24. No. 2, p. 513–548.

10. Schmitt M.N. Israel’s Operation Rising Lion and the Right to Self-Defense, June 16, 2025, https://lieber.westpoint.edu/israels-operation-rising-lion-right-of-self-defense .

11. Yoo J. International law and the war in Iraq // American Journal of International Law. 2003. Vol. 97. #3, p. 563–576.

1. Grotius H. Law of War and Peace. M.: Ladomir, 1994. p. 196.

2. Dinstein Y. War, aggression and self-defense. CUP, 2005. p. 185

3. Kretzmer D. The Inherent Right to Self-Defense and Proportionality in Jus Ad Bellum // European Journal of International Law. 2013. Vol. 24. 1. p. 235-282. For a critique of this position see: Nolte G. Multipurpose Self-Defense, Proportionality Disoriented: A Response to David Kretzmer // Ibid. pp. 283-290. Note, G. Nolte writes that the principle of proportionality may limit but not extend the right to self-defense; the introduction of new objectives, such as the deterrence of aggressors, cannot be justified by arguments derived from the right to self-defense per se.

4. See: Schmitt M.N. Preemptive Strategies in International Law // Michigan Journal of International Law. 2003. Vol. 24. No. 2. P. 513-548

5. Schmitt M.N. Preemptive Strategies in International Law // Michigan Journal of International Law. 2003. Vol. 24. No. 2. P. 535

6. See: Ministerial Meeting of the Coordinating Bureau of the Non-Aligned Movement. Caracas, Venezuela 20-21 July 2019, Final Document, para. 39.2.

7. See: Greenwood Ch. The legality of the use of force: Iraq in 2003 // Bothe M. et al. (eds.) Redefining Sovereignty: the Use of Force after the Cold War. Transnational Publishers, 2005. p. 387-416; Yoo J. International law and the war in Iraq // American Journal of International Law. 2003. Vol. 97. #3. p. 563-576