International law does not permit regime change in Iran Philippe Sands

In 2003, the United States and Britain waged a war to rid Iraq of weapons of mass destruction that it turned out not to have.

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A "big fat mistake" Donald Trump would call it, aided by the benefit of hindsight. Manifestly illegal and a political catastrophe, most people now conclude. Two decades on, Israeli prime minister Benjamin Netanyahu’s decision to attack Iran to prevent it from making a nuclear weapon raises anew the same question. Can it be lawful to use military means to frustrate a country’s capacity to develop or use a weapon of mass destruction at some point in the future?

The rules of international law have not changed since Iraq. Broadly, they allow military force to be engaged in two circumstances: if authorised by the Security Council (the British claim in relation to Iraq was implausible then, and not even argued today), or in “exercise of the inherent right of individual or collective self-defence if an armed attack occurs”, as Article 51 of the UN charter puts it. The latter is the implicit but unstated rationale put forward by Israel, in a letter sent to the UN Security Council. The use of force is to “neutralise the existential and imminent threat from Iran’s nuclear weapon and ballistic missile programs”, Israel argues, to “thwart the threat of imminent attacks” and “prevent Iran from acquiring nuclear weapons,” against the background of the Iranian regime’s “openly declared plan to annihilate the state of Israel”. In this regard, some argue that Israel’s attack is to be assessed in the context of an ongoing military conflict that involves Iran’s proxies, including Hamas, Hezbollah and the Houthis.