Israel's attacks on Iran amount to crime of aggression, legal scholars say

Middle East Eye

a day ago

Israel's attacks across Iran on Friday, which targeted "dozens" of sites including nuclear facilities, military commanders and scientists, are manifestly illegal, leading scholars of international law have said.
Accusing the government in Tehran of beginning to build nuclear warheads, Israeli Prime Minister Benjamin Netanyahu said the attack was aimed at "rolling back the Iranian threat to Israel's very survival", adding that it would take "many days".
"We struck at the heart of Iran's nuclear enrichment programme," Netanyahu said in a recorded televised address.
"We targeted Iran's main enrichment facility in Natanz. We targeted Iran's leading nuclear scientists working on the Iranian bomb. We also struck at the heart of Iran's ballistic missile programme."
Netanyahu's decision is premised on "preventive self-defence" arguments, which justify the use of force against another state to prevent an anticipated future attack.
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However, such an argument is inconsistent with the rules governing the use of force under international law, including the limited justifications for the use of force established by the United Nations Charter and the prohibition of the crime of aggression.
The use of force is only lawful if it seeks to repel an imminent attack or one that is underway, experts have explained.
International law scholar Marko Milanovic said that the stated goals of Israel this time are about preventing a future nuclear attack by Iran. It is not a response to an attack that has started, or one that is imminent. Iran has yet to obtain any nuclear weapons. Therefore, there was no threat of an imminent attack justifying preemptive self-defence.
'It cannot reasonably be argued that Iran would imminently attack Israel, or that using force was the only option to stop that attack'
- Marko Milanovic, legal scholar
There are three positions with respect to the right to self-defence under international law, explained Milanovic in an article for Ejil Talk.
The first is that states can use preventive self-defence to deflect future anticipated threats, in particular those perceived to be existential. The second is that states can use force with the aim of preempting future attacks that are imminent, and the third is that states can only resort to the use of force when attacks have already occurred.
According to Milanovic, the use of force to prevent a future attack, as used by Israel in its Friday operation, is considered 'legally untenable' by the majority of international lawyers.
"Israel's use of force against Iran is, on the facts as we know them, almost certainly illegal," he wrote.
Article 2 (4) of the UN Charter prohibits "the threat or use of force against the territorial integrity or political independence of any state".
'No self-defence at all'
The only justification for the use of force is outlined in Article 51 of the UN Charter, which is to respond to an attack that is underway.
"Unless Israel is able to provide substantially more compelling evidence than is currently publicly available, it cannot reasonably be argued that Iran would imminently attack Israel, or that using force was the only option to stop that attack," said Milanovic.
"Israel is therefore using force against Iran unlawfully, in violation of Article 2(4) of the Charter. It is committing aggression."
The crime of aggression is one of the four core international crimes under the Rome Statute of the International Criminal Court (ICC), alongside genocide, crimes against humanity, and war crimes. It refers to the planning, preparation, initiation, or execution of an act of aggression, or use of force in violation of the UN Charter, by a person in a leadership position, such as a head of state or senior military commander.
Other scholars on Friday also accused Israel of committing the crime of aggression.
Professor Kevin Jon Heller of the University of Copenhagen said: "Few acts are more unequivocally illegal than preventive (non-imminent) self-defence. So Israel's attack is both unlawful and criminal - the crime of aggression."
"Israel's attack on Iran is not simply a violation of the UN Charter. It is a manifest violation of it," he wrote on X.
Sergey Vasiliev of the Open University of the Netherlands also qualified the attack as falling under the crime of aggression.
"This operation is an unlawful use of force," he wrote.
"Iran presented no imminent threat to Israel that would justify such an attack. This is an act of aggression."
Netanyahu's justification for Friday's attack is similar to arguments made by Russia to justify its invasion of Ukraine, said Milanovic, or those used by the US to justify the use of force against Iraq.
"The problem with this approach is that it is so boundless that it completely eviscerates the prohibition on the use of force - a state could act whenever it perceives an existential threat," argued Milanovic.
"In short, this 'preventive' form of self-defence is simply not self-defence at all."
According to Jon Heller, while the US has taken the same position as Israel only occasionally, "Israel is the only state that has unequivocally endorsed the right of preventive self-defence."