Operation Midnight Hammer: Legality, Sovereignty, and the Collapse of Nuclear Non-Proliferation Norms

• Under “Article 2(4) of the UN Charter”, member states are prohibited from using force against another state’s territory or political independence.
• Iran’s Foreign Minister denounced the air strikes as a “grave breach of sovereignty,” asserting that the targeted sites were civilian and operated within the terms of the NPT and the UNSC Resolution.
• If Iran retaliates by closing the Strait of Hormuz, the strikes might cause oil prices to skyrocket, which would affect economies around the world.
• By establishing precedents that enable Russia and China to subvert “US hegemony” through UN vetoes or support for Iran (e.g., arms, nuclear technology), these transgressions undermine the foundation of the “UN Charter”.

On June 22, 2025, the United States conducted airstrikes on Iran’s Fordow, Natanz, and Isfahan nuclear facilities, escalating tensions in the Middle East, with Iran condemning the airstrikes as a “grave violation” of sovereignty. The United States, on June 22, 2025, Iran’s airstrikes on Fordow, Natanz, and Isfahan have been met with international legal as well as diplomatic condemnation, first and foremost on the issue of their legality as a matter of international law. 

The United Nations Charter, an early international treaty that governs the use of force by states, is at the centre of the legal argument. By “Article 2(4) of the Charter”, member states are prohibited from using force against another state’s territory or political independence. Except where the “UN Security Council” authorises force in Chapter VII, or where a state engages its inherent right of self-defence under Article 51, but only “if an armed attack occurs Under the US-led “Atoms for Peace” initiative, Iran’s nuclear program got underway in the late 1950s. A 1957 nuclear cooperation agreement called for the construction of a 5 MW research reactor in Tehran by 1967. Supported by the United States, France, and Germany, Iran pursued civilian nuclear energy under the Shah with plans to build 23 power plants by the 1970s after ratifying the “Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in 1970”. This was upset by the Islamic Revolution of 1979, which resulted in Western sanctions that pushed Iran toward covert development in the 1980s and 1990s with help from China, Russia, and Pakistan.

Concerns shifted from civilian to possibly military in 2002 when expatriate opposition groups exposed unreported facilities at Natanz and Arak, drawing attention from the IAEA. The dual-use aspect of the program permits claims for civilian energy, but the development of ballistic missiles and enrichment capabilities raises concerns about proliferation. Iran’s enrichment had reached 60% by the early 2020s, which is close to the 90% weapons-grade threshold. “IAEA” studies noted that Iran had enough stockpiles for several bombs if it were further enriched, but no weaponisation was verified. Concerns around the world have increased due to recent decreases in breakout time (perhaps weeks) and undeclared nuclear material.

Ironically, the program’s foundation was built by early US cooperation, but post-revolution restrictions (such as arms sales and UN vetoes) strengthened Iran’s ties with China and Russia and encouraged its defiance. As Saudi Arabia and Turkey pursue nuclear capabilities amid perceived double standards, the program’s expansion is entwined with proxy wars (Yemen, Syria), oil market volatility (disturbances in the Strait of Hormuz impact 20% of the world’s supply), and the potential for a regional arms race.

Iran denounces recent US bombings on its nuclear facilities (such as those in Fordow, Natanz, and Isfahan) as abuses of sovereignty under “Article 2(4) of the UN Charter”, which forbids using force against a state’s territorial integrity. Under “Article 51’s self-defence clause”, the US claims collective self-defence for Israel against an “imminent threat,” but this is controversial because, according to the “1837 Caroline case”, pre-emptive strikes require an “instant, overwhelming” threat, which is not backed by the IAEA’s conclusion that there is no weapons-grade uranium. The struggle undermines multilateralism, gives adversaries like China and Russia more power, and jeopardizes regional and economic stability by encapsulating a conflict between international law’s standards for sovereignty and perceived security concerns.

On  June 27, 2025, a letter to the “UN Security Council”, the United States attempted to legitimise the attacks by invoking Article 51, arguing that the action was one of collective self-defence of Israel. The US administration argued that the recently emerging Iranian nuclear enrichment program was an “imminent threat” to regional security that justified pre-emptive action. However, this is weakly based in law, as pre-emptive self-defence—striking first to prevent a future threat is exceedingly contentious in international law. The classic precedent in this matter is the “1837 Caroline case”, which held that to meet the requirement of anticipatory self-defence, the threat must be “instant, overwhelming, and leaving no choice of means, and no moment for deliberation.” There should be definite proof of an impending and direct armed attack. In this case, no such attack has been made by Iran against the United States or Israel. 

Moreover, the “International Atomic Energy Agency (IAEA)” in its June 2025 report had determined that Iran’s nuclear program, enriched to 60% (below 90% weapons-grade level), remained under IAEA safeguards and inspection regimes. This removes the “imminent threat” justification since no production or possession of nuclear weapons by Iran had been proven at the time of the attacks.

The June 22, 2025, US airstrikes on Iran's nuclear facilities as a part of Operation Midnight Hammer are against the “UN Charter”, “NPT”, and “Resolution 2231”, Iran's “grave violation” argument asserts.

Leading international law experts have condemned the attacks.  In the Journal of International Criminal Justice, Professor Ben Saul described the American action as a likely “crime of aggression”, in breach of the jus ad bellum principles of necessity and proportionality. The U.S., Saul contended, failed to try to exhaust diplomatic means (as under “Article 2(3) of the Charter” or seek Security Council authorisation, both of which were conditions under the Charter regime of lawful use of force.

Iran’s Foreign Minister denounced the air strikes as a “grave breach of sovereignty,” asserting that the targeted sites were civilian and operated within the terms of the “Nuclear Non-Proliferation Treaty” (NPT) and “UNSC Resolution 2231,” which ratified the “Joint Comprehensive Plan of Action” (JCPOA) in 2015. Iran was also supported by the “Non-Aligned Movement” (NAM), which made a statement condemning the attacks as “unprovoked” and calling for an International Court of Justice (ICJ) inquiry. In this context, the US airstrikes provide a harmful precedent of unilateral force on legal rationales, eroding the UN Charter as well as the international non-proliferation regime and rule of law. The law designed to safeguard state sovereignty and regulate international peace and security appears to have been put aside for tactical reasons, raising pressing concerns over accountability, precedent, and the future of multilateral diplomacy.

The cornerstone of international law is “Article 2(4)”, which protects sovereignty by forbidding the threat or use of force against a state’s political independence or territorial integrity. By striking civilian facilities (under IAEA safeguards) without “UN Security Council approval under Chapter VII”, the only legal justification for force outside of self-defence, US airstrikes on Iran’s nuclear sites violate this. Individual or group self-defence is only allowed under Article 51 “if an armed attack occurs.” Israel’s collective self-defence is justified by the US, which points to Iran’s nuclear program as an “imminent threat.” According to the Caroline case, international law, however, stipulates that a threat must be “instant, overwhelming, leaving no choice of means, and no moment for deliberation,” with unmistakable proof of an imminent attack.

The “imminent” assertion is undermined by IAEA reports that affirm Iran’s enrichment at 60% below weapons-grade and without any evidence of military diversion. Because it runs the risk of establishing unilateral force in the absence of specific threats, pre-emptive self-defence is extremely controversial. Because of the IAEA’s oversight and the fact that Iran did not launch an armed attack against the US or Israel, the attacks violate the jus ad bellum standard (necessity, proportionality). Legality is further undermined by the US’s failure to use all of “Article 2(3)”’s mandate for peaceful dispute resolution (such as IAEA mediation or UN sanctions).

By establishing precedents that enable Russia and China to subvert “US hegemony” through UN vetoes or support for Iran (e.g., arms, nuclear technology), these transgressions undermine the foundation of the “UN Charter”. If Iran retaliates by closing the Strait of Hormuz, the strikes might cause oil prices to skyrocket, which would affect economies around the world. The Global South’s uneasiness is reflected in the “Non-Aligned Movement’s” (NAM) denunciation, which strengthens Iran’s victim narrative and encourages appeals for the “International Court of Justice” (ICJ).

Iran Foreign Minister Abbas Araghchi denounced the attack as a “grave violation” of sovereignty, claiming they targeted “peaceful nuclear facilities under IAEA supervision” and breached the “UN Charter”, “NPT”, and “UN Security Council Resolution 2231”, in favour of the 2015 JCPOA. “Article 2(3) of the Charter enforces peaceful settlement of disputes”, but the US shunned IAEA mediation or UN sanctions. The NAM, with 120 states, stood with Iran, denouncing the attack as “unprovoked” on June 25, 2025, and appealing for an ICJ investigation, evidencing Global South unease at unilateralism.

Iran’s nuclear program started in the 1970s under the Shah with US support for civilian energy under the NPT, ratified by Iran in 1970. The 1979 Islamic Revolution resulted in Western sanctions, compelling Iran to a clandestine program. The undeclared Natanz and Arak facilities were revealed in 2002, resulting in IAEA reports of NPT non-compliance. The 2015 JCPOA restricted Iran to 3.67% enrichment and imposed inspections, but the 2018 US withdrawal compelled Iran to 60% enrichment by 2023. The IAEA found no weapons-grade uranium before the attacks, corroborating Iran’s assertion of a “peaceful” program.

There exists a correlation that the infringement of sovereignty incites humanitarian and ecological threats, since assaults on populated cities like Isfahan risk civilian deaths and contamination. The legal precedent of evading UN mechanisms disempowers non-proliferation regimes, and popular indignation in Iran, amplified by “NAM”, connects legal violations to geopolitics, lending legitimacy to its request for “ICJ action”. The US-Iran nuclear cooperation deal under “Atoms for Peace,” which included training and a research reactor, marked the beginning of Iran’s nuclear adventure in 1957. The Shah’s plan for 23 nuclear power plants in the 1970s, supported by Western technology, established the groundwork for dual-use capabilities (enrichment and reprocessing) while aiming for energy independence. Iran pledged to use it for civilian purposes under “IAEA” protections when it ratified the NPT in 1970.

The "imminent" assertion is undermined by IAEA reports that affirm Iran's enrichment at 60% below weapons-grade and without any evidence of military diversion.

Western cooperation was terminated by the “Islamic Revolution of 1979”, and sanctions forced Iran to pursue covert development. By the 1980s, Iran was looking to China, Russia, and Pakistan (the A.Q. Khan network) for technology related to uranium extraction and enrichment. Facilities in Natanz and Arak were exposed in 2002, exposing unreported activities that violated NPT reporting requirements and prompting IAEA investigations and UN Security Council sanctions (2006-2010). Supported by UNSC Resolution 2231, the 2015 JCPOA restricted centrifuges, set a 3.67% enrichment cap, and required stringent IAEA inspections to lift sanctions.

Following the Trump administration’s 2018 US withdrawal, which reinstalled “maximum pressure” sanctions, Iran resumed enrichment at rates of 20% by 2020, 60% by 2021, and recently close to 90% using sophisticated centrifuges. Stockpiles for many bombs, if further enriched, are highlighted in IAEA reports, and fears about breakouts (weeks to a bomb) are raised by undeclared material and limited monitoring access.

Iran can assert peaceful purposes due to the program’s dual-use character, but suspicions are heightened by ballistic missile developments and enrichment thresholds. Iran’s suspension of further protocol inspections and recent IAEA discoveries of undeclared nuclear material make verification more difficult and raise the risk of proliferation.

In terms of geopolitics, the US withdrawal from “JCPOA” pushed Iran closer to China and Russia, escalated proxy wars (such as those in Yemen and Iraq), and prompted Saudi Arabia and Turkey to explore nuclear options, raising the possibility of a regional arms race. The airstrikes bolster Iran’s ties with China and Russia, which offer technology (such as Chinese missile components and Russian nuclear reactor support) and diplomatic cover (such as UN vetoes). As both nations use the precedent to defend their own policies elsewhere (such as in Ukraine and the South China Sea), this puts US hegemony in jeopardy.

Iran might retaliate by closing the “Strait of Hormuz”, which handles 20% of the world’s oil, which would raise prices and cause recessions around the world. This pushes Iran into the BRICS economic frameworks and exacerbates the economic burden already caused by sanctions.  Saudi Arabia and Turkey may pursue secret nuclear projects, breaching the “NPT”, because they are concerned by Iran’s threshold position and the US’s double standards. This is similar to past instances where regional instability was sparked by violations of sovereignty (such as Iraq in 2003).

In line with Iran’s claims of sovereignty, the 120 member states of the “NAM” denounce the strikes as unilateral and call for an ICJ investigation. This strengthens the mistrust of Western-led orders in the Global South, supporting Iran’s narrative and making global diplomacy more difficult. “Article 2(4)” is violated by the strikes, undermining sovereignty norms and encouraging enemies to violate them in kind. The validity of the Charter is undermined when non-proliferation regimes are at risk of collapsing due to the failure to get “UN Security Council” permission or to use all of the peaceful channels allowed by “Article 2(3)”, such as “IAEA” negotiations.

There are humanitarian concerns and protection of civilians relating to IHL violations wherein the “Geneva Conventions Protocol I (1977)” outlaws attacks on infrastructure “essential to civilian survival” or inflicting disproportionate harm. The Natanz and Isfahan attacks, near civilian homes, are IHL issues. The US termed “surgical” strikes, but Maxar Technologies satellite imagery shows perimeter building damage, which suggests collateral damage. Iran experienced no radiological contamination, and Saudi Arabia experienced no regional rises in radiation, but IAEA Director General Rafael Grossi reported destroyed uranium inventories to be “latent threats.” A 2021 report by the UNEP observed that an attack on nuclear facilities would have “long-term health effects from radiation exposure.” “The Geneva Conventions” prohibit attacks on “installations holding dangerous forces” such as nuclear installations, and the US failure to release risk assessments raises questions regarding compliance with IHL’s precaution and proportion principles. The correlation is that Humanitarian risk is linked to environmental risk since pollution risks civilian health. The UN Charter breach is reflected in the IHL breach, reinforcing Iran’s case in law.

Iranian public opinion, viewing the attacks as an “attack on civilian security,” consolidates anti-Western determination, which makes non-proliferation diplomacy more difficult. “The 1977 ENMOD Convention and UN General Assembly Resolution 47/37” discourage environmental warfare that “causes widespread, long-term environmental damage.” Bombing uranium enrichment plants potentially contaminates soil and groundwater, though there are no prompt increases in radiation. Iran’s post-attack suspension of IAEA cooperation denies independent evaluation, raising suspicions. India’s NAM promotion of a binding environmental warfare convention highlights the necessity for greater protection.

The attacks disabled the “JCPOA”, which constrained Iran's enrichment up to the 2018 US pullout.

Environmental threats pile up on top of humanitarian concerns, as pollution exposes civilians to danger. “ENMOD” legal transgression is equivalent to UN Charter violations, strengthening Iran’s multi-faceted legal case. Widespread Western doubts regarding nuclear management, as expressed by NAM, undermine NPT compliance, linking environmental standards to non-proliferation concerns. In the US, right-wing media like Fox News hailed the strikes as a “decisive victory,” backing Trump’s claim about “obliterating” Iran’s nuclear program. Left-wing observers were incensed at the lack of Congressional or UN approval. Protest rallies in Qom and Tehran in Iran protested the strikes as an “assault on sovereignty,” while diaspora communities demanded ICJ action. On X, the NATO leader justified the strikes as “legal,” and Iranian leaders labelled them a “crime of aggression,” providing polarised accounts. Iranian public outcry resounds with legal grievances, doubling demands for ICJ relief. Polarised media coverage fuels diplomatic tensions, compromising “JCPOA” restoration. Unreported humanitarian and environmental emergencies fuel anti-Western sentiment, connecting public opinion with non-proliferation failure.

The attacks disabled the “JCPOA”, which constrained Iran’s enrichment up to the 2018 US pullout. Iran’s near-90% post-attack enrichment and “IAEA” pause are indicators of a possible NPT withdrawal, as occurred with North Korea in 2003. Saudi Arabia and Turkey’s two-standard nuclear worries could provoke clandestine programs, undermining the NPT. The lawbreaking circumvention of IAEA and UN channels most directly undermines non-proliferation structures. Humanitarian and environmental threats underpin claims that compliance with the NPT will provoke aggression. Iranian domestic opinion and NAM’s calls for reform join past suspicion with present diplomatic frustration. Iran’s enrichment has progressed from 3.67% (JCPOA-compliant) to 60% by 2021 and near-90% recently, with IAEA estimates suggesting enough low-enriched uranium for multiple bombs if processed to weapons-grade. Breakout time has shrunk from over a year (pre-2018) to weeks, per recent assessments, due to advanced centrifuges and undeclared material. Iran’s ballistic missile program, capable of delivering nuclear payloads, heightens threats, though no weaponisation is confirmed. Reduced “IAEA” access since 2021 (e.g., suspended additional protocol) complicates verification, raising global stakes.

These developments fuel fears of Iran nearing a nuclear threshold, prompting US/Israeli pre-emptive considerations but risking broader escalation (e.g., proxy wars, oil disruptions). The strikes’ precedent may push Iran toward “NPT” withdrawal, as North Korea did in 2003, destabilising non-proliferation. The June 22, 2025, US airstrikes on Iran’s nuclear facilities as a part of Operation Midnight Hammer are against the “UN Charter”, “NPT”, and “Resolution 2231”, Iran’s “grave violation” argument asserts. Iran’s project, from its 1970s inception to the “JCPOA collapse”, places its peaceful intention in perspective. “NAM” solidarity underpins Global South opposition to unilateral action. The humanitarian, environmental, and non-proliferation impacts of the airstrikes are interconnected, where legal violations fuel public outrage and diplomatic failure. UN-led investigations and new nuclear governance must rebuild multilateral confidence and prevent regional destabilisation.

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Dr Lakshmi Karlekar & Tanishaa Pandey

Dr. Lakshmi Karlekar is an Assistant Professor at the School of Humanities – Political Science and International Relations, Ramaiah College of Arts, Science and Commerce, Bengaluru. She holds a PhD in International Studies from CHRIST (Deemed to be) University. Tanishaa Pandey is a BBA LLB student at the School of Law, CHRIST (Deemed to be University), Central Campus, Bengaluru. Views expressed are the author’s own.