US-Israeli attack on Iran: Under what conditions can an illegal war claim moral legitimacy?

In international relations, manifestly illegal government action can sometimes be morally defensible. While historical examples of legitimacy trumping legality are few and far between, they do exist.

The question of whether the joint US-Israeli war on Iran is one such case demands more attention than it has received so far.It should be beyond dispute that the initiation of this war by US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu flagrantly violated international law, even if many of their allies have shown a willingness to fudge this issue. Iran did not pose a threat to either country—from nuclear weapons, conventional missiles or state-sponsored terrorism—of an imminence or on a scale that could possibly justify, in the absence of the United Nations Security Council’s approval, preemptive military action as a form of self-defence.

The US and Israel acted when they did not because of Iran’s strength, but because of its relative weakness. The attack is just the latest in a series of actions by the world’s most powerful countries—including Russia’s invasion of Ukraine, China’s militarization of the South China Sea and America’s seizure of Venezuelan President Nicolás Maduro—that disdain international law.

The collapse of whatever is left of the rules-based order is bad news for the rest of the world. It demands concerted pushback from capable middle powers, as Canadian Prime Minister Mark Carney compellingly argued in his landmark Davos speech in January.Nonetheless, can one still argue that, whatever the law, the monstrous crimes of Iran’s theocratic leadership justify its military decapitation? The charge sheet against the regime, both at home and abroad, is long and ugly, culminating in the