This chapter identifies a set of principles to aid application of international law amid the complexity of modern warfare.
Armed conflicts today are increasingly characterized by various forms of cooperation. This research paper has sought both to outline the international legal challenge arising from this fact and provide a roadmap to establish who is party to an armed conflict. The paper has not sought to exhaust all legal questions pertaining to cooperation in war and has, in particular, not examined the ius ad bellum questions of when military assistance amounts to a use of force or an armed attack. Instead, the paper has sought to clarify precisely how and when states, international organizations and armed groups become co-parties to an armed conflict, and the implications that flow from this status. Because co-party status has significant legal implications – and may also have considerable political implications – it is crucial that states, international organizations and non-state armed groups are aware of when the line to becoming a co-party is crossed.
The following recommendations are intended to identify a set of principles to aid practical application of the ideas in this paper. Applying these principles in practice will be challenging. But doing so in good faith is crucial, to ensure that international law’s regulation remains effective amid the complex reality of today’s wars.
The following section sets out as the key recommendations of the research paper:
- That the following principles be applied to the identification of co-party status in armed conflict:
- At the outset, to qualify as a potential co-party, an entity must meet the party-related criteria governing international and non-international armed conflicts independently. That is, parties to an international armed conflict (IAC) must be states (with the exceptions listed in Section 1.2) and parties to a non-international armed conflict (NIAC) must independently meet the threshold of organization.
- The conflict-related criteria governing IACs (i.e. resort to armed force) and NIACs (i.e. protracted armed violence) can be met by the conduct of the co-parties taken cumulatively.
- The acts constituting co-party status must be attributable to the collective entity for it to be considered a co-party.
Co-party status is to be established according to two cumulative criteria:
i) The acts of the purported co-party are directly connected to hostilities; and
ii) There is some degree of cooperation or coordination between the purported co-party and the other party that they support.
- These two criteria inherently presuppose that a co-party acts with knowledge of the facts that establish the direct connection to hostilities and the element of cooperation or coordination.
- Whether the legal criteria for co-party status are met in a given case is determined by an objective assessment of the facts.
- Once established, co-party status persists until such time as the legal criteria for that status cease to be met, and that change in situation has attained a degree of stability and permanence.
- That caution is warranted to avoid three common misunderstandings that have been regularly present in the public discourse on co-party status:
- ‘Becoming a co-party to a conflict necessarily entails an illegal act.’ In fact, becoming a co-party and the legality of the acts that determine party status are separate questions. Whether a state, international organization or non-state armed group becomes a party depends solely on whether the legal criteria set out in Recommendation 1 are fulfilled. Whether the acts carried out by that prospective co-party are lawful depends notably, in inter-state conflicts, on whether force is used in self-defence on the side of the victim of an armed attack – as permitted by the ius ad bellum. By contrast, if the acts that make a state a party to an inter-state conflict amount to participation in aggressive war, they are prohibited by that body of law.
- ‘If a state becomes a party to a conflict it necessarily entitles the adversary under international law to attack that state.’ In fact, whether or not the adversary is entitled to use force against a party to the armed conflict depends on the ius ad bellum rules on the use of force by one state against another (see Section 3.1). Being a co-party does not affect the applicability of the ius ad bellum. Any conduct by a co-party that constitutes a use of force must have a justification under the UN Charter, so that it does not violate Article 2(4). However, the rules of international humanitarian law regarding lawful targets will also apply.
- ‘Supporting a party to a conflict involves breaking the law of neutrality and therefore makes the supporting state a party.’ Co-party status does not necessarily arise as a consequence of violations of neutrality law (see Section 2.1). The law of neutrality has nothing to say on when the line to co-party status is crossed. Co-party status and neutrality are separate legal questions.
- That states, international organizations and non-state armed groups consider the benefits of making public, wherever possible, whether they determine themselves to be co-parties, and the reasons for taking that view where they assist others that are parties to an armed conflict. This transparency would carry several possible advantages:
- Securing trust both domestically and internationally that the international law applicable to their actions is understood and can be implemented with the necessary legal certainty;
- Countering confusion and anxiety in public discourse and bad-faith claims by other actors regarding who is a co-party; and
- Actively shaping the development of international law on this point.
- That states, non-state armed groups, as well as international and humanitarian organizations – for the same reasons – consider whether it is practicable to release publicly any determinations made concerning the status of those assisting parties to an armed conflict.
- That political reasons for not taking particular actions – valid as they may be – are not confused with the legal implications of becoming a (co-)party.
- That, in determining their course of action in an armed conflict, states, international organizations and non-state armed groups are aware of how becoming a co-party determines the rules that apply to their conduct (and how these rules apply), to their relationship with third parties and to individuals connected to them.
- That co-parties take appropriate measures to comply with their positive obligations in relation to their fellow co-parties in the conduct of hostilities, and regarding the protection of individuals in armed conflict.