Interpreting the right of nations to self-defence

Hindustan Times

25-06-2025

President Donald Trump has claimed credit for facilitating a tentative ceasefire in West Asia. However, the US's attack on Iran's nuclear facilities earlier had exacerbated a volatile situation in West Asia, stemming from the ongoing conflict between Israel and Iran. While the political and strategic repercussions of these strikes will be analysed, a critical question arises: Does the American attack violate international law? Let's explore this question on three levels. American strikes against Iran's nuclear facilities are legally suspect. (AFP)
First, as per Article 51 of the UN Charter, States can use force in international relations as part of their inherent right to self-defence 'if an armed attack occurs'. Consequently, the use of force not aimed at repelling an ongoing armed attack is inexplicable under the right to self-defence. Since there has been no armed attack by Iran on the US, as per this interpretation, the actions of the US do not meet the criteria of Article 51 and are, therefore, illegal.
Second, some scholars and States argue that interpreting the right to self-defence solely as a means to repel an ongoing armed attack is too restrictive. They believe this perspective fails to address the threats posed by terrorism and nuclear dangers that pervade the contemporary world. Hence, it is contended that countries should also be able to invoke the right to self-defence against armed attacks that have not yet occurred. However, this broader interpretation could be perilous, as it may allow States to justify the use of force against other countries under the pretext of self-defence for geopolitical motives or other reasons, potentially constituting acts of aggression.
To prevent a broad interpretation of the right to self-defence in anticipation of an armed attack, it is argued that States must demonstrate the requirement of immediacy. This means that, for a State to justify using force against an armed attack that has not yet occurred, it needs to show that the attack is imminent or about to happen. In this sense, imminence has a temporal aspect. In such situations, States invoking self-defence should demonstrate that they had no time for deliberation and were compelled to use force in response to, as Malcolm Shaw argues, a threat that is 'reasonably and evidentially perceived to be imminent'. So, was an armed attack from Iran on the US imminent? Based on the publicly available evidence, it does not appear to be the case, which renders American strikes on Iran illegal.
There is an additional dimension to the theory of immediacy. In the past, the US has attempted to broaden the definition of imminence by disconnecting it from the temporal aspect. As Dapo Akande and Thomas Liefländer put it, a State may use force if there is a highly probable and severe threat, even if that threat is not imminent in time, provided that the force used is necessary and proportionate, i.e., there would be no future opportunity to eliminate the threat. Assuming this legal argument is valid, the US would need to demonstrate that the nuclear threat from Iran was both highly probable and severe. This would be challenging to prove as Iran does not yet possess a nuclear weapon. There is also uncertainty about when Iran might acquire this capability, with estimates ranging from weeks to years, and these assessments have been discussed over several years.
For the sake of argument, let us assume that the Iranian nuclear threat is both highly probable and severe. Even in this case, it would still be arduous to justify the necessity of the American military strikes, as the US and Iran were engaged in negotiations regarding the nuclear issue. Therefore, the US had alternative methods available to address the nuclear threat, and the bombing of the nuclear facilities was not the last window of opportunity to prevent a nuclear attack in the future.
Third, can the US justify this attack as an act of collective self-defence? It is important to remember that Article 51 recognises not only the inherent right of individual self-defence but also of collective self-defence. As Christopher Greenwood argues, the International Court of Justice, in the US v. Nicaragua case, established three elements to justify the right of collective self-defence.
First, there must be a State that has been the victim of an armed attack. Second, this State must formally declare itself as a victim of that armed attack. Third, the victim State should request assistance from the State that seeks to justify its use of force under the right to collective self-defence. In this case, the US cannot justify the use of force against Iran under the principle of collective self-defence, as there has been no armed attack from Iran on Israel.
Therefore, Israel is not a victim State in the current scenario that could seek assistance from the US. Furthermore, Israel's attacks on Iran on June 13, which Tel Aviv describes as pre-emptive strikes against Iran's perceived nuclear threats, are legally questionable.
Some may argue that the conflict did not begin on June 13 of this year but instead on October 7, 2023, or even earlier, with attacks on Israel by terrorist groups like Hamas and the Houthis, which Iran patronises. However, this expansive interpretation risks blurring important lines in the conflict.
Thus, no matter how one slices it, American strikes against Iran's nuclear facilities are legally suspect. These strikes raise gravely alarming questions about the double standards of powerful countries, in this case the US, in their respect for the already fragile rules-based international order.
Prabhash Ranjan is professor and vice dean (research), Jindal Global Law School. The views expressed are personal.