In June 2025, the fragile equilibrium of the Middle East was once again disrupted when Israel launched a series of coordinated airstrikes on Iranian nuclear facilities at Natanz, Esfahan, and Fordow. Citing an imminent threat posed by Iran’s advancing uranium enrichment programme and the potential weaponisation of nuclear material, Israeli Prime Minister Netanyahu declared the operation a matter of national survival. The strikes, which occurred with limited prior warning, have triggered renewed debate over the legality and strategic prudence of unilateral pre-emptive military action.
Iran’s Nuclear Programme
The geopolitical landscape surrounding Iran’s nuclear programme has long constituted a central axis of tension in US-Iran relations, reflecting broader regional rivalries and international security concerns. Since the 1979 Iranian Revolution, bilateral ties have oscillated between sporadic cooperation and entrenched hostility, shaped by mutual distrust and diverging strategic objectives. Iran’s pursuit of nuclear capabilities, coupled with its support for regional proxy groups and its growing influence across the Middle East, has repeatedly intensified these tensions. While Iran has consistently asserted that its nuclear activities are for peaceful purposes, both the US and Israel view its programme with deep suspicion, particularly the latter, which perceives any Iranian nuclear capability as an existential threat. This perception had fuelled repeated discussions in Israeli security discourse concerning the potential for pre-emptive strikes, with Prime Minister Netanyahu, as early as February 2025, urging the US to ‘finish the job’, a request declined at the time.
Iran, in turn, has cultivated deliberate ambiguity regarding its nuclear intentions. As a signatory to the 1970 Non-Proliferation Treaty (NPT), it is bound by an international legal framework for nuclear oversight. However, its compliance has increasingly come under scrutiny. Despite not officially withdrawing from the 2015 Joint Comprehensive Plan of Action (JCPOA), Iran has exceeded key enrichment thresholds, prompting threats from European states to refer the matter to the United Nations Security Council. It has also constructed fortified underground facilities at sites such as Natanz, designed to withstand conventional attacks and even US bunker-busting munitions. These installations have withstood repeated sabotage attempts, including Israeli cyber and kinetic operations, underscoring Iran’s resilience and strategic resolve.
Consequently, the International Atomic Energy Agency (IAEA) was tasked with monitoring Iran’s nuclear activities in late 2024 and early 2025. The agency then reported uranium enrichment levels surpassing 60%, nearing weapons-grade thresholds, alongside restricted access to inspection sites. These developments have fuelled suspicions that Iran is maintaining strategic ambiguity, deliberately obscuring the extent of its nuclear progress while avoiding overt violations that would trigger unified international condemnation.
The June 2025 Israeli Strike
On 13 June 2025, Israel initiated a comprehensive military campaign against Iran’s nuclear facilities, targeting sites in Isfahan and Natanz. The operation, reportedly named ‘Operation Rising Lion,’ involved a combination of aerial bombardments and cyber operations aimed at crippling Iran’s nuclear capabilities. Israeli officials claimed that the strikes significantly damaged Iran’s uranium enrichment infrastructure, setting back its nuclear program by years. However, independent assessments suggest that while the attacks caused substantial damage, they may have only delayed Iran’s nuclear ambitions by a few months. In response, Iran condemned the Israeli strikes as violations of its sovereignty and international law. The Iranian government vowed retaliation, stating that ‘all options are on the table.’ Subsequently, Iran launched missile attacks on Israeli military sites and reportedly activated proxy groups in the region to carry out further strikes. Therefore, the US, under President Trump, expressed support for Israel’s action, framing it as a necessary step to counter Iran’s nuclear ambitions. The US military conducted its own strikes on Iranian sites, further escalating tensions.
The European Union called for restraint and urged all parties to return to diplomatic negotiations to prevent further escalation. European leaders emphasised the importance of dialogue in addressing the nuclear issue and maintaining regional stability. Russia and China, similarly, strongly condemned the Israeli and US actions, labelling them as violations of international law and calling for an immediate ceasefire. Both countries expressed deep concern over the potential for further destabilisation in the Middle East.
The timing and legality of the strikes have sparked significant debate. Critics argue that the attacks may have violated international law, particularly the principles of sovereignty and non-intervention. Supporters contend that the strikes were a legitimate exercise of preemptive self-defence, given the perceived imminent threat posed by Iran’s nuclear program. The international community remains divided on this issue, highlighting the complexities of applying international legal norms to such situations.
The Theory of Preemptive Self-Defence
Under Article 51 of the United Nations Charter, the right to self-defence is triggered only in the event of an armed attack and is conditioned on immediate notification to the UN Security Council. This restrictive interpretation, codified by UN General Assembly Resolution 3314 (1974), affirms that any act of self-defence must conform to the principles of necessity and proportionality, permitting only those measures strictly required to repel an ongoing or imminent assault. Within this framework, the expanding discourse around anticipatory, pre-emptive, or preventive self-defence, advanced notably by the United States in recent decades, sits uneasily within established international legal norms. Though not formally recognised under positive international law, the doctrine of pre-emptive self-defence has been invoked in state practice, generating sustained legal controversy due to its susceptibility to subjective threat perception and potential misuse. A crucial distinction persists between anticipatory self-defence, as articulated in the 1837 Caroline case, recognising that forces may be used only in response to an instant threat, leaving no choice of means; and preventive war, which targets hypothetical future dangers and remains broadly prohibited under contemporary international law.
Israel’s approach to self-defence has long operated in the ambiguous space between these doctrines. Its 1967 pre-emptive strike against Egypt, which launched the Six-Day War, was retrospectively presented as a necessary response to an imminent Arab offensive, though its legal justification remains contested. Similarly, the 1975 incursion into Palestinian camps in Lebanon and the 1981 bombing of Iraq’s Osirak nuclear reactor, based on suspicions of potential militarisation, reflect a strategic doctrine rooted in existential pre-emption. In each case, Israel defended its actions as indispensable to neutralising unfolding threats, yet the imminence and necessity of such operations have been the subject of enduring legal and scholarly debate. Therefore, the June 2025 strike on Iranian nuclear sites adheres to this historical logic but raises fresh legal and normative challenges. Although Iran’s nuclear programme has exceeded the constraints of the JCPOA and remains shrouded in opacity, it is officially classified as civilian, with no verifiable evidence of weaponisation. Some legal scholars argue that speculative intelligence and uncertain intent fail to satisfy the threshold of lawful anticipatory self-defence. Nevertheless, Israeli officials contend that Iran’s continued uranium enrichment and the reinforcement of fortified sites such as Natanz constitute a de facto military threat necessitating urgent disruption.
Iran’s strategy of deliberate opacity further complicates any clear legal assessment. By exploiting ambiguity, Tehran maintains strategic deterrence while avoiding definitive legal culpability. Israel’s invocation of this ambiguity to legitimise preemptive strikes, in the absence of a demonstrable armed attack, thus highlights the erosion of consensus surrounding the lawful use of force. Meanwhile, continued US support, either tacit or overt, echoes post-2002 trends that appear to favour a norm of permissibility for preemptive action. This development not only challenges the integrity of the UN Charter system but also raises serious implications for global nuclear governance and the legitimacy of international legal restraint.
By Charlotte Soulé, Rise to Peace intern and Masters of International War Studies student at University College Dublin