This post addresses some issues raised in two recent publications, in leading periodicals by Michael Schmitt and Casey Biggerstaff and Russel Buchan, regarding the relationship between jus ad bellum and the law of State responsibility. It seems that both contributions tend to conflate the law of the use of force with the law of State responsibility and to favour analogies between the two areas of law that do not hold on a closer inspection.
The analysis by Schmitt and Biggerstaff of the US-led military assistance to Ukraine is centred around the notion of indirect use of force, meaning “certain aid or assistance to another State’s use of force, or to an armed group’s actions that would qualify as such a use if engaged in by States.” They suggest that “that support to a party to an armed conflict can rise to the level of a use of force under Article 2(4) and customary international law.” The key issue, according to them, is “the extent to which the aid or assistance has impacted that use of force” by the State which receives that aid and assistance and how much that State benefits from the assistance given to it (197, 204, 226-227). This no doubt relates to the real-life dynamics of the relevant armed conflict, but is that factor alone sufficient to generate a fresh legal concept with which international law is, by and large, unfamiliar?
That a creation of a fresh legal concept can raise issues or concerns across various underlying areas of international law is essentially echoed in the authors’ own thesis that “whether the aid or assistance itself amounts to a use of force requiring a “circumstance precluding wrongfulness,” like self-defense, to be lawful”. They also admit that State practice has not properly embraced this thesis yet (192-193). The key analytical question here is that there has to be wrongfulness (or its material content at the very least) involved in the relevant situation before we can speak of how it could be precluded. And Schmitt and Biggerstaff indeed seem to assume that the “indirect force” in question could amount to a wrongful act unless some legal principle precludes its wrongfulness (190). The victim State, in that putative case of the provision of military aid and assistance to Ukraine growing – factually and legally – into the use of force against Russia, would be Russia itself. It would be entitled to reparations and to undertaking countermeasures against the USA and its allies. A first use of force against a State could then be classified as an act of aggression against that State. That would radically alter the current legal position according to which Russia is the aggressor and Ukraine is the victim of the aggression, which also means that military assistance given to Ukraine does not amount to an internationally wrongful act, for a simple reason that it does not infringe upon any State’s legal rights (much as it plays an important role in the overall dynamics of this armed conflict). A potential ground for responsibility of aiding and assisting States could arise if Ukraine uses their aid and assistance to perpetrate violations of international humanitarian law or human rights law. Another potential ground of wrongfulness of this military assistance could be sought in the law of neutrality. But in this latter context, owing to the aggressor discrimination principle (explained here, here and here) the provision of military assistance to the victim of aggression does not amount to an internationally wrongful act. As for collective self-defence, the International Court has clarified that the victim State has to expressly request other States’ help by way of collective self-defence (p.120). Ukraine may have been keen on this, but no State has acceded to such requests coming from Ukraine yet. Collective self-defence turns on the fulfilment of those stated legal requirements, not simply on political combination on the ground and is, for that reason not relevant (yet) to the Ukraine war.
It is clear, therefore, that the argument of Schmitt and Biggerstaff tries to use the notion of “aid and assistance” – originally applicable to one State’s complicity in another State’s internationally wrongful act (Article 16 ILC’s Articles on State responsibility) – in relation to lawful activities by third States undertaken in the context of the Ukraine conflict. Their argument is that owing to its extent and material impact this aid and assistance could no longer be a mere aid and assistance but should be characterised as an indirect use of force.
Overall, the rationale behind the distinction between the use of force against a State and provision of assistance to an agent that fights a war against that State is eminently clear: a use of force consists in actually fighting an enemy, while the provision of aid assistance is merely preparatory or contributory to such fighting, in the sense that it enables the aided and assisted State to do that fighting in the first place or to do the same with greater efficiency or to a greater extent. Each relevant entity undertakes different autonomous action and incurs a different degree of blameworthiness, all depending on who does what in the relevant situation. The Article 16 ASR question is qualitatively different from the use of force question, unless the aid and assistance given to the State committing an act of aggression or violations of international humanitarian law is of such nature and magnitude that in essence enables the recipient State to commit those wrongful acts; in which case the “aiding and assisting” State effectively – in fact and in law, that is – becomes a co-perpetrating State and could, as a co-delinquent, be responsible for the entirety of the wrongful outcome (see here, 84-91 and 108-113). The assessment of the aiding and assisting State’s conduct under the law of State responsibility would still remail separate from the qualification jus ad bellum would bestow to the same conduct.
By contrast, if the aid and assistance given to the victim of the aggression could be classified as an indirect use of force against the aggressor State, then the State providing this aid and assistance – in this case USA and their allies – could risk becoming, in the legal sense, parties to an international armed conflict with Russia. The scale and intensity of aid and assistance they provide to Ukraine, as Schmitt and Biggerstaff depict it, would then be legally equated to a sustained military confrontation between US and their allies, on the one hand, and Russia, on the other. All that is needed for this rather novel and unexpected outcome to materialise is, it seems, the legal system’s endorsement of their novel concept of “indirect force”, and then let States and their governments cope with a plethora of legal and political consequences which this putative outcome would generate.
Schmitt and Biggerstaff continue that “a breach of the prohibition [of the use of force] by a supporting State does not depend on attribution of the supported State’s use of force but instead upon the former’s own actions in support of the latter’s use of force” (198, emphasis original). But how could a supporting State possibly breach that prohibition without first entering into an armed confrontation with the victim State and its territory? The most typical standard accepted in international practice to determine whether a State does any of that is the causation standard, focusing on whether the State has enabled or failed to prevent the use of force by a non-State entity against another State. There is nothing “indirect” in the State action if it causally generates the violation of jus ad bellum, in which case the State itself becomes an author of an armed attack and, depending on the circumstances of the case, a party to an international armed conflict as well. Moreover, the non-State actor situation, even if referred to in 1970 Friendly Relations Declaration, is not directly relevant to the Ukraine situation because here it is about one State arming another State. Schmitt and Biggerstaff do rely on the Nicaragua dictum at paragraph 228 that the USA was responsible for breaching jus ad bellum because it had armed rebels fighting against the Nicaraguan Government (205). Apart from the fact that 1970 Declaration focuses on the State’s autonomous role in causing harm to another State (manifested through the State’s organisation of, participation in, or acquiescence into the relevant activities), it is also plainly clear that the issue of the provision of arms to non-State actors cannot be generalised to State-to-State collaboration. As explained in detail (at pp.92-93), relations between States and relations between States and non-State entities are informed by different ontologies, and what holds true in one context cannot be easily generalised to another context. In our present context, there is a significant difference between a State helping another State to defend itself against the aggressor and a State using non-State entities for intruding into another State’s territories. The law is unlikely to tolerate any analogy as between these widely diverging situations.
Like Schmitt and Biggerstaff, Buchan is more enthusiastic about jus ad bellum and less keen on the ordinary law of State responsibility. To Buchan, self-defence under Article 51 UN Charter can be an overall framework within which States could lawfully resort to the variety of non-military responses to unlawful uses of force – responses that would otherwise be illegal (2). To justify this rather broad approach, Buchan further traces the origins of the law of self-defence in the ancient law of self-preservation (7). This is a rather problematic analogy because, as explained earlier here and here, self-preservation and self-defence are essentially different concepts with essentially different components and premises; there is, further, no continuity between the pre-UN Charter practices and jus ad bellum as codified in the UN Charter (focusing, among others, on the requirement of a factually occurring armed attack which did not feature in the concept of self-preservation). The UN Charter did not leave the previous customary law on the use of force intact; instead, the correct view would be that the modern customary law about jus ad bellum has emerged under the influence of the Charter. Other illustrations of Buchan’s expanded view of self-defence include the equalling of the imminence standard with the anticipatory self-defence; and the often-used argument that States are entitled to use force against other States in response to the attacks perpetrated by non-State entities from the latter States’ territories (28). However, these arguments are also problematic, because international law does not accept that anticipatory self-defence is lawful; nor, despite the academic enthusiasm to the opposite effect, does international law allow States to use force against other States in response to attacks emanating from non-State actors (as explained earlier here, here, here, here, and here).
A reader is bound to wonder why the law of countermeasures cannot enable States to undertake non-military responses to unlawful uses of force. To all intents and purposes, aggressive use of force is an internationally wrongful act; and moreover, international law does not ordinarily mind States from adopting responsive measures owing to the existence of the state of war between two or more States. On this front, Buchan justifies the above broad narrative on self-defence by invoking the inadequacy of other institutions of international law, such as the law of countermeasures. He suggests that international law prohibits third-party countermeasures (27), which means that third States could not lawfully use countermeasures to react to Russia’s war in Ukraine. The illegality of third-party countermeasures is, however, not a right premise: for, apart from the fact that the ILC has left the issue open in its Articles on State responsibility, Buchan’s argument might well lead to the conclusion that the bulk of third State measures against Russia post its activities in Crimea and the rest of Ukraine from 2014 onwards are illegal. And, while collective security and collective defence treaties often envisage the adoption of both military and non-military measures in response to an act of aggression, such treaties do not apply to every use of force in the world; more importantly, those treaties do not adversely affect the distinction that general international law (jus ad bellum aspects of which are also reflected in the UN Charter) draws between military and non-military coercive measures.
Under current positive international law, third-State economic coercive measures against the State authoring an act of aggression are third-party countermeasures. Buchan cites cases from practice in which several States have invoked self-defence to rationalise their non-military measures, for instance in the aftermath of the invasion by Argentina of Falklands and NATO measures further to 9/11 attacks in 2001 (15). However, what States say on various occasions is less important than how the law characterises the relevant process or activity. There is nothing in the relevant economic measures and other measures such as intelligence sharing or overflight clearances that international law considers to be tailored specifically to the jus ad bellum contexts. These measures could be suitable to be adopted in situations not involving an armed conflict at all, and whether within or outside NATO. NATO’s 2001 invocation of Article 5 of the North Atlantic Treaty was, therefore, purely symbolic. More generally, the law of self-defence is narrower and more specific than the general law of State responsibility, and it does not endorse any false symbolism through which its principles could be appropriated by any national political agenda which finds the language of self-defence to be useful.
To summarise, the key to the Schmitt and Biggerstaff argument is that jus ad bellum envisages the use of force by one State against another State without the two engaging into military confrontation with each other; Buchan’s argument is that the range of non-military activities that do not require the occurrence of an armed attack at all could be undertaken mostly (if not only) as part of self-defence under Article 51 UN Charter which warrants forcible measures in situations no other than those involving the occurrence of an armed attack. Both lines of reasoning involve a significant methodological and analytical confusion. Institutions of positive international law exist owing to the general consent of States and they serve their discrete functions assigned to them by the legal system. Drawing artificial analogies between these institutions is unlikely to find any support in the general consent on States on which the existence of these institutions rests.