Party Status to Armed Conflict

Editor’s note: This post is part of a book discussion on Alexander Wentker’s “Party Status to Armed Conflict in International Law“.

The following comments are offered from the perspective of a government lawyer but very much on a personal basis; they do not necessarily represent the views of the UK Government.

The relationship between academic scholarship and the practical application of international law by States and other actors has always been a close, indeed a symbiotic, one.  After all, the analysis and study of international law is to a very large extent focused on what States and others say and do – or should say and do – whilst legal scholarship has always provided an essential resource tool for the practitioner and indeed a subsidiary source of law itself.

That said it is still remarkable to find a work of scholarship which, given when Dr Alex Wentker started his research, has proved so prescient in addressing a topic which has become of current and real importance to the international community and which equally provides, through a rigorous examination of key concepts, practical criteria for determining when actors become co-parties to an armed conflict. The sober title Party Status to Armed Conflict in International Law might not be one to grab the immediate attention of a hard-pressed government official or diplomat but the heading of last year’s Chatham House paper Joining In Wars – in whose drafting and elaboration Alex played a central role – emphasises the political, military and diplomatic, as well as legal, significance of the issues at the heart of his book.

The Law of Armed Conflict can of course claim to be one of the longest established and, as regards its core treaties, most widely ratified areas of international law. Its main rules and principles – distinction, humanity, proportionality, military necessity – are readily understood; even if respect for those rules remains the perennial and primary concern.  But it is striking how often fundamental issues about its application – its geographical and temporal scope, the classification of conflicts and so on – arise. Changes in military technology, the nature of armed conflicts and of those taking part, and increasingly complex patterns of international cooperation perennially require dusting off neglected areas and concepts of international law and re-assessing them in the light of wider legal developments.  Russia’s aggression against Ukraine – and the issues around the support provided by others to Ukraine and to Russia – has in particular put the issue of who is, and is not, a party to an armed conflict firmly on the legal and political agenda.

In the first part of his book Alex looks afresh at the seemingly familiar concept of being a party to an armed conflict – grounding it in the notion of war being conducted between collective entities and setting out why party status, and the rights and obligations which international law attach to party status, remain fundamental. In doing so, as he does throughout the book, Alex moves with clarity and rigour across a complex range of legal regimes and concepts – spanning not just IHL but the ius ad bellum, State responsibility and the law of neutrality.

It is with the last of these, and more generally with the status of third parties, that one starts to get into the most topical issues. As Alex demonstrates, the law of neutrality still subsists after the UN Charter, but the extent to which, and how, it is does so remain matters of debate. It is particularly notable how few States have referenced neutrality in relation to support for Ukraine. And whatever its current content and relevance, it is clear from the analysis in Part II of the book that the law of neutrality as such has no role in determining co-party status.  

It is this analysis in the second part of the book of the legal framework for identifying party status – and in particular the elaboration of criteria for co-party status in multiparty conflicts – which is perhaps the most innovative aspect of the work and of   the most direct practical utility for those advising of these issues.

It is above all the first criterion – direct connection to hostilities – which is the heart of the analysis. We are not of course concerned with self-evident cases where a State’s armed forces are directly engaged in combat operations – or at the other end of the spectrum with political, financial, humanitarian assistance, or the general supply of military materiel. It is rather the range of logistical, intelligence, advisory, cyber and other support, including use of territory and airspace, which may or may not be sufficient to make an actor a co-party to the conflict. Such a criterion will inevitably need to be assessed case by case – no two situations are identical. But that is true of many areas of international law and IHL in particular.

It is worth recalling that this analysis has had to be done in a context where there are no express provisions in IHL treaties setting out the criteria for becoming a co-party or explaining the legal consequences; and where many elements have had to be elaborated from contextual interpretation and practice. Alex describes his approach as deductive and then inductive – he (reasonably) does not purport to derive his criteria from an analysis of State practice. That said he approaches the elaboration of the criteria with good practical sense. While governments would not necessarily endorse every aspect of the analysis, the criteria certainly provide a helpful starting point and a test which is informed by, and close to, actual State practice. More debatable perhaps is the extent to which co-party status as such then confers additional legal obligations over and above those that that parties would in any event have under particular IHL provisions or general rules of State responsibility.

Party Status to Armed Conflict in International Law therefore provides not just a significant contribution to the literature in this field but one of immediate and practical relevance. I would underline three aspects from that practical perspective.

First, as mentioned, is the political resonance, and topicality, of the issue. Deciding whether one has become a party to an armed conflict is a matter to be determined against objective, legal criteria – ensuring that the correct body of law is applied. But this is not simply a technical, legal issue. It also has huge political and military significance – not only as one’s own forces may be targeted under IHL, but also because of the political impact, domestic and international, of determining that one is “joining in a war”.

A key function of the rules in this area is to limit and contain the spread of conflict. In the three years since the Russia’s aggression against Ukraine, NATO and other States have been clear that their supply of military equipment to Ukraine does not make them a party to the conflict – an analysis supported by the criteria elaborated in this book. But the nature and level of support remains a highly sensitive issue and is approached with great care and rigour.  

The scope for misunderstanding and miscalculation, and escalation, by an adverse party remain real. One’s own analysis may have limited value if those already party to the conflict read the situation differently and respond accordingly. By seeking to establish clear thresholds and criteria the book makes a valuable contribution to managing those risks.

Secondly, the book confirms the practical importance of distinguishing between the different legal regimes which may apply. The law in practice is not of course neatly compartmentalised. Different legal regimes – on the use of force, IHL, State responsibility, the law of neutrality and so on – can apply, and have to be assessed, in parallel.

In particular, the relationship between the ius ad bellum and the law of armed conflict ius in bello is one which preoccupies specialists. It is therefore not surprising that it can cause confusion for political leaders, the media and wider public. As the book makes clear, becoming a party to armed conflict is about applying IHL– it says nothing about whether the underlying use of force is lawful. A State can accept that it and its adversary are in an armed conflict, and bound to comply with IHL, and still take the view that the adversary’s use of force is in violation of the UN Charter.

Equally even if a State is not a co-party, that is far being the end part of the story.  Its actions in support of a party to an armed conflict can still engage its obligations under the law of State responsibility and specific treaties. These are matters which are again addressed with great care and rigour and to which considerable attention and resource are devoted.

Thirdly and finally, the book requires us to think carefully about the specific nature of being a co-party – as opposed to being party to a bilateral conflict. Perhaps most notable is the assessment that the threshold for becoming a co-party to an existing armed conflict can be lower than that required to establish the existence of an international or non-international armed conflict – that is recourse to armed force or the intensity of hostilities. In short, a State can more readily find itself a party to an existing conflict – and indeed without its armed forces themselves using force. It is a salutary reminder of the importance and sensitivities of this issue. And one on which the book contributes timely and much-needed guidance and clarity.