Professor Alexander Orakhelashvili
The background
The current military conflict between Israel and Iran, which has begun on 13 June 2025, has attracted substantial discussion on legal justification of Israel’s use of force against Iran. So far, there have been not many including mostly Israel’s own communication to the UN Security Council on 17 June, itself rather sparse on legal detail, and Australia’s position discussed here. A greater discussion has been witnessed through academic commentaries, however. There are views that Israel’s attacks on Iran could be defended as (anticipatory) self-defence or that, alternatively, Israel is acting in the context of a wider and ongoing international armed conflict and hence the legality of its actions have to be assessed under jus in bello. These two lines of argument could be formulated only as alternatives. If a State’s use of force is lawful response to a preceding armed attack under jus ad bellum, the jus in bello requirements provide a further set of guidance in terms of what targets could be lawfully attacked. However, if a use of force is illegal under jus ad bellum because it is not a response to a preceding armed attack, then it is by and large irrelevant how the relevant offensive military operations could be assessed under jus in bello, because the whole use of force would be illegal and there would be no backdoor legalisation of steps taken as part of an act of aggression. Except that, the attacked State (in this case Iran) would remain bound to respect international humanitarian law.
The debate and arguments
While commentators more readily accept that jus ad bellum does not justify attacks on Iran, there is a greater enthusiasm for the alternative line of argument based on jus in bello. For instance, Amichai Cohen and Yuval Shany have suggested that Israel’s action could be justified as “an act of military escalation in the context of an ongoing war”. They further refer to Ori Pomson who discusses the issue of an ongoing armed conflict in conjunction with the notion of “indirect use of force” that has recently been brought up by academic writers. As clarified here, the adherence to this rather open-ended and vague notion is only bound to unpredictably widen the range of cases in which States would feel freer to resort to the use of force against other States without being in fact attacked by the latter.
The irrelevance of “indirect use of force” leaves us with the ordinary criteria of the existence of an international armed conflict, in this case between Israel and Iran, as of any point of time preceding 13 June 2025 when Israel started using force against Iran. The difficulties arising with such legal argument are both juridical and evidentiary. If, as it appears to be, the doctrinal claim is that Iran is in an armed conflict with Israel through non-State entities such as Hamas, Hezbollah or Yemeni Houthis, the key criterion for rationalising this claim would be the “effective control” test adhered to by the International Court of Justice in the cases of Nicaragua in 1986 and Bosnia Genocide in 2007 (para. 404 where the Court also rejected the relevance of ICTY’s “overall control” test). More broadly, while the “effective control” test is primarily one of the law of State responsibility, its relevance also extends to jus ad bellum and jus in bello as well. As explained here in some detail, for a State (in this case Iran) to engage in an international armed conflict with another State (in this case Israel), it inevitably has to use force, through the action of its own organs, against the latter State. That has to happen in fact, much as Cohen and Shany refer to the belief entertained by Israel, because the existence of an international armed conflict has to be judged on objective facts, not on beliefs.
The ”substantial involvement” criterion (as per GA Res.3314) that Cohen-Shany and Pomson discuss, is a jus ad bellum criterion; it does not displace the “effective control” requirement but instead is conditional upon it or other criteria endorsed in Nicaragua such as direct control. Therefore, a State would be liable for the use of force against another State and launching an international armed conflict against it only either it gets substantially involved, through its own State organs, into a non-State entity’s attacks; or if has such control over that entity that the latter could be fairly described its de facto organ; or if it can be proven that a State actually takes decisions and specific performs military operations the way that could show that the State’s control over those operations is an “effective control”.
It seems that neither of the above claims could be supported by evidence. While there are multiple indications that Iran’s relations with Hamas, Hezbollah or Yemeni Houthis are close and cooperative, or that they share common political vision or mutual sympathy, that is by far not the same as Iran exercising control over those non-State entities’ activities in any of the senses described above. I am not suggesting that it could not be otherwise. A definitive answer to this question requires sufficient privity to classified information available in several jurisdictions. And secrecy is only a part of the problem here, because any such claim has to be made good in public, and be supported by evidence that could be pleaded before and approved by an international court or tribunal that would be assessing claims as to facts in the light of the legal requirements such as the effective control test. Furthermore, both on juridical and evidentiary terms, it would have to be shown that the putative armed conflict between Iran and Israel has not only begun at a certain time or subsisted over a certain period – on which the Cohen-Shany point on general close of military operations is contingent – but also, crucially, that it has been subsisting through the two States’ sustained military confrontation right up to 13 June 2023.
At present, and unless the detailed and convincing evidence to the opposite effect emerges, the chances making any such claim good appear to be rather dim.
On the jus ad bellum side of the debate, Ryan Goodman discusses the armed attack requirements and refers to the statement in the Addendum to the 8th Report on State responsibility by Special Rapporteur Roberto Ago, to the effect “if the attack in question consisted of a number of successive acts, the requirement of the immediacy of the self-defensive action would have to be looked at in the light of those acts as a whole.” (para.122, emphasis added). It is rather clear that Ago refers to a single attack consisting of several interrelated steps (rather than generically disparate steps making up a putative armed attack, which would be a too overstretched use legal fictions at the service of political agenda). Speaking in the context of the immediacy to an attack from a temporal perspective, Ago discusses, from the legal point of view at least, one and same “armed attack” that is marked by the generic similarity of steps undertaken as part of it, by their coincidence in time, and/or some form of close relation going beyond the mere political aims or agenda or statements of intention or threat. The attack in question – one to which an armed response is lawful – has to be the attack in the legal sense, not simply an adverse material occurrence, and on Ago’s view this happens when various steps taken by a State are generically, locationally or temporally so interrelated that they do not, in the relevant context, amount to separate armed attacks (though they might do so if, in a different context, they were to be perpetrated separately). In other words, an “armed attack” is an ongoing attack, and the law does not allow for self-defence to be used in the time between various putative “armed attacks”.
The outlook
It is clear that jus in bello claims cannot be made good, and the same applies to jus ad bellum claims. The only way in which jus in bello could be relevant is its activation through Israel’s use of armed force against Iran on 13 June 2025. At that point, it is plausible to say that a new armed conflict has begun and the occurrences over past few days witnessed sustained armed confrontation between the two States. This is the only feasible ground on which jus in bello could be relevant at all in the present context and both parties are bound by it, especially by the law stated in 1949 Geneva Conventions and 1977 First Additional Protocol. Legality of the war under jus ad bellum remains a separate issue.
A possible escalation of this armed conflict remains another risk and this has been manifested by certain conduct and statements by the American Government. President Trump has called through social media upon Tehran’s population to “immediately evacuate”. In further remarks, he demanded Iran’s unconditional surrender. And then, he has uttered further remarks on Iran’s Supreme Leader, on terms reassuring and threatening at one time, to the effect that “We are not going to take him out (kill!), at least not for now. … [though] Our patience is wearing thin.” One wonders who exactly “we” is in this context, the USA alone or USA and Israel together; because this would help clarifying whether the USA controls Israel’s some decisions at least, or intends to engage in combat actions against Iran together with Israel or independently. On that front, we have to await further developments to see whether the much-discussed question of how many parties an armed conflict could have requires a renewed discussion.