NECESSITY WITHOUT IMMINENCE: OPERATION OPERA (1981), ANTICIPATORY SELF-DEFENCE AND THE LIMITS OF ARTICLE 51, FROM OSIRAK TO IRAN

Author

Anushka Singh, Adarsh Jain, Kshitij Gondal

Abstract

 On 7 June 1981 Israeli aircraft destroyed the Osirak reactor near Baghdad, a French-built research reactor that had not yet been loaded with fuel and was operating under International Atomic Energy Agency safeguards. Israel justified the attack as self-defence against a future nuclear threat, arguing that once the reactor became operational it could no longer be attacked without releasing radioactivity over Baghdad. Twelve days later the Security Council, including the United States, unanimously condemned the attack as a clear violation of the Charter of the United Nations. Operation Opera has since become the reference point for every debate about striking nuclear programmes before they produce weapons, and it returned to the centre of international legal argument after the Israeli and American strikes on Iranian nuclear facilities in June 2025. This article re-examines the operation through the lens of necessity. It argues that the debate has been confused by two different uses of that word: necessity as a condition of lawful self-defence under Article 51 of the Charter and customary law, and necessity as a circumstance precluding wrongfulness under Article 25 of the Articles on State Responsibility. Neither, properly understood, can justify the 1981 attack. Measured against the temporal requirement of imminence, the operation was preventive rather than anticipatory; measured against the requirement of necessity, it was undertaken while diplomatic and institutional alternatives remained available; and the plea of necessity under the law of State responsibility cannot excuse a use of force contrary to a peremptory norm. The article then traces the operation's legal afterlife, from the collective condemnation of 1981 through the preventive-force debates of 2002 to 2005 and the 2025 strikes on Iran, and argues that the durable lesson of Osirak is institutional rather than doctrinal: the question is not only when force may be used against a nuclear programme, but who is entitled to decide.

Keywords

Anticipatory self-defence; necessity; imminence; Article 51 UN Charter; Operation Opera.

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References

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