This analysis examines the joint Israeli and United States military attacks against Iran in June 2025, which aimed to dismantle Iran's nuclear program. The author, Mary Ellen O’Connell, argues that these attacks fundamentally violated international law, specifically the UN Charter’s comprehensive prohibition on the use of force (Article 2(4)), as the actions were based on the political theory of deterrence/preemption rather than the lawful requirement of an "armed attack occurring" (Article 51). While Iran was the victim of an armed attack and retaliated, its responses are critiqued for failing the necessity and proportionality requirements, as they were motivated by "sending a message" (deterrence) rather than genuine defensive purpose. The analysis rejects arguments based on "ongoing armed conflict" and new interpretations of "imminence," concluding that compliance with the plain terms of the UN Charter, not the Cold War deterrence playbook, remains the only sure path to international peace.
U.S. Attacks on Iran: Defying the Law to Follow a Theory
The Conflict (Beginning): On 13 June 2025, Israel initiated air attacks against Iranian nuclear sites and military targets, including targeted assassinations. The United States joined approximately ten days later, launching significant missile and bomb strikes without involving Congress. Iran retaliated against both nations.
The Legal Casualty: Thousands of casualties resulted from the conflict. Crucially, the author argues international law was also a casualty, noting that NATO Secretary General Mark Rutte, UK Prime Minister Starmer, and German Chancellor Merz wrongly praised or justified the attacks, undermining the ideal of law over force.
Peremptory Norm: The core legal principle is UN Charter Article 2(4), which is a comprehensive and peremptory (unshrinkable) ban on the use of force. Concerns about nuclear weapons must be resolved through peaceful means, the UN Security Council, or treaties.
Strict Self-Defense Requirement: The only express limitation on Article 2(4) is Article 51, which grants the right to individual or collective self-defense if an armed attack occurs. This right is only to "halt and repel" existing attacks, not to preempt potential future attacks.
Iran’s Failure to Meet Legal Requirements: Iran, though the victim of an armed attack, failed the general principles of international law, specifically necessity and proportionality, in its counter-attacks. Iran’s strikes, particularly against Qatar, were deemed "all show" and part of the "deterrence game" (sending a message) rather than meeting a defensive purpose, which is not permitted under law.
Rejecting "Ongoing Armed Conflict": The author counters justifications claiming an "ongoing armed conflict" exists between Israel and Iran. Intermittent events, like tit-for-tat exchanges or one-sided violence (assassination, terrorism by militias), do not meet the international law definition of armed conflict (intense fighting lasting a day or more).
Rejecting "Imminence" Interpretation: The analysis firmly rejects attempts to replace the Article 51 phrase "if an armed attack occurs" with "imminent." Treaty interpretation demands adherence to the plain meaning of the words, which requires evidence of an attack occurring ("sine qua non").
The Deterrence Playbook: The actions of Israel, the U.S., and Iran are attributed to following the outdated, dangerous Cold War deterrence playbook, rather than adhering to the clear, sharp norms of the UN Charter, which are essential for maintaining international order.
Call to Action (Conclusion): Quoting legal experts Louis Henkin and Hersch Lauterpacht, the author stresses that manipulating the Charter’s language for self-serving political ends undermines peace. Peace requires practicing the law of the Charter and utilizing alternatives to force.