The killing of Iran’s supreme leader, Ayatollah Ali Khamenei, by a US-Israeli strike is a targeted assassination of a head of state. It also marks a grave escalation in a region already burdened with smouldering wars and fragile states. The consequences of the deliberate strike will reverberate across a Middle East marked by the aftershocks of foreign intervention. Revulsion against the hardline regime in Tehran, or the desire for a better future for the Iranian people, does not confer a legal justification.
Force is lawful, under the UN charter, only in self-defence against an imminent attack or with security council approval. Neither condition has been met. There was no evidence of an “instant, overwhelming” Iranian attack being prepared. What Donald Trump’s Operation Epic Fury looks like is not pre-emption but prevention: a decision to eliminate a future risk while an enemy appeared weak. It is a war of choice. Mr Trump’s call to overthrow a sovereign government was extraordinary.
Unlike pre-emptive wars, preventive ones are deemed unlawful because they grant the powerful licence to strike at will. The distinction is important; it is why many European governments rejected Russia’s justification of its invasion of Ukraine by claiming to head off a future threat. Law cannot be optional for allies and binding only for adversaries. The domestic foundations of Mr Trump’s action are also shaky. There’s little public support in the US for this attack, and Congress was not asked to authorise hostilities. There will be even less appetite as the civilian death toll mounts and US soldiers come home in bodybags.
The war may have been launched swiftly but its consequences are likely to be long-lasting. Iranian retaliation has gone beyond Israel to Gulf monarchies where US forces are deployed. Tehran says it has closed the strait of Hormuz, through which roughly 20% of the world’s oil exports pass. Analysts warn crude prices could jump 50% to $100 a barrel. Escalation is no longer notional. Tehran’s strategy appears less about battlefield victory than survival – demonstrating that, despite leadership decapitation, it can fight on. It is a gamble. Excessive restraint by Iran invites humiliation; overreach risks forging a broader coalition against it.
Khamenei’s death is a moment of rupture. But large, cohesive states rarely collapse just under air assault. Regime change from the sky has repeatedly proved an illusion – in Afghanistan, Iraq and Libya. Removing leaders is not the same as remaking a country’s politics. Perhaps Mr Trump wants a compliant Tehran, as his illegal kidnapping of Nicholás Maduro has given him in Venezuela. However Mr Trump’s decision to bomb Iran when negotiations, mediated by Oman, had shown signs of a breakthrough will narrow the space for future compromise.
The question is not just whether Mr Trump’s war weakens Iran. It is whether it weakens the system of rules on which global stability depends. Once preventive war is normalised, it can be used by any state that considers itself threatened in the long term. That is a dangerous precedent in an age of expanding missile arsenals, cyberthreats and nuclear proliferation.
The idea that complex societies can be reshaped by external force is not new. It almost never works. Mr Trump’s triumphalism after Khamenei’s killing is worrying especially when what is needed is restraint from all. The moment requires cool heads – and to stand up for the legal principles that, however imperfectly observed, remain the best defence against a world governed by raw power alone.
