Among the issues separating the American understanding of international law regarding transnational non-state actor armed groups from that of the "international community" (or at least an influential and significant part of UN officialdom, international law academics, international tribunals, international human rights NGOs, and governments particularly in Europe) is whether it is even possible for a non-state actor to mount an "armed attack" against a state, within the meaning of the UN Charter. The question is legally elemental--so fundamental that differing answers given by the US and the "international community" amount to conceptual ships passing in the night.
Relatively few scholars seek to bridge the gap in fundamental legal views, but Kimberly N. Trapp's recent posting to SSRN, "Can Non-State Actors Mount an Armed Attack?" marks a welcome exception in the academic literature. The paper is slated to appear as a chapter in the forthcoming Oxford Handbook on the Use of Force (OUP, ed. M. Weller); it is brief and concise, written in the clear, plain language that distinguished her earlier 2011 OUP book (reviewed by me for Lawfare, along with Noam Lubell's also highly relevant Extraterritorial Use of Force Against Non-State Actors), State Responsibility for International Terrorism. Abstract:
Article 2(4) of the United Nations (Charter prohibits the use of force between States, but that prohibition does not “impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations”. In its Charter incarnation, the prohibition of the use of force is situated in a strictly inter-State context, and does not speak to the phenomenon of uses of force by Non-State Actors (‘NSAs’). The question examined in this Chapter is whether the exception to that prohibition–the right to use force in self-defence–is nevertheless responsive to the war-making capacity of NSAs or whether it is limited to a snapshot of the right as it may have been conceptualised in the immediate aftermath of a global conflict between States. Otherwise put, is the definition of ‘armed attack’ in Article 51 of the UN Charter (and related customary international law) conditioned on the attacker being a State?
The legal stakes are substantial. If a non-state actor cannot be deemed to have launched an "armed attack" within the meaning of the Charter, then (other things equal) there appears to be no "inherent right of individual or collective self-defence" against the group that launched the attack. Whatever rights the state has to act against the group within its own sovereign territory, its rights to act beyond its own borders and particularly within the territory of another state (assuming that actions of the non-state actor are not legally attributable to that other state) are very limited, to the extent they exist at all. Whatever the "inherent right" of self defense means under the Charter, and whatever the limitations and constraints on self-defense might be with respect to the territory of other states, these arguments never even get going. The right of self-defense has not been triggered.
Moreover, even today's persistent, heated debates over the meaning of "imminence"--the ability of a state to invoke self-defense against an "imminent" threat--do not apply here. Why not? Because doctrines of imminence are a special case within self-defense--but self-defense rights are not triggered on this legal view (whether by threat or by actual attack, it doesn't matter), because absent a legally cognizable connection to a state, the non-state actor that threatens or actually undertook the attack lacks the legal characteristics in international law even to launch an "armed attack" within its legal meaning. All of this is irrespective of the extent of the actual attack or its real-world consequences. (Cf. 9/11.)
On the other hand, if a non-state actor can be deemed to have launched an "armed attack" within the meaning of the UN Charter, then self-defense rights are triggered. In that case, it might seem obvious (and does seem obvious, to Americans, anyway) that a right of self-defense on its own terms authorizes the use of force up to and including the conduct of hostilities amounting (in practical and legal terms) to an "armed conflict." For critics, however, this is not obvious at all; yet more argument over those (putative) self-defense rights and their extent turns out to be yet another area of legal ships passing in the night. The US, for its part, takes the view that inherent self-defense rights, including against non-state actors, run all the way up to forcible responses that, in practical terms, might constitute the conduct of hostilities and, in legal terms, might constitute an "armed conflict." This is the view of all three branches of the US government--the United States is currently engaged in an armed conflict against Al Qaeda and its associated forces under the terms of the post-9/11 AUMF. The adversary is a non-state actor, and the law of armed conflict applies, including the law of targeting and detention.
Critics of the US position, for their part, deny that self-defense rights automatically mean that a state is able to vindicate those rights by undertaking--and invoking the law of--armed conflict against a transnational non-state actor. These critics would say that there cannot be an "armed conflict" conceived "transnationally" against a non-state actor, even if the non-state actor (against which the state, arguendo, has self-defense rights), operates transnationally and so, presumably, must be addressed transnationally as a practical matter. On this view, therefore, the United States cannot avail itself of the law of armed conflict and its legal regime authorizing (while regulating and limiting) "first resort to lethal force." Self-defense rights, on this view, at most would allow some limited resort to force--one that would have to be cabined, however, not in the law of armed conflict but instead within international human rights law.
Non-state actors cannot, by legal definition on this view, mount armed attacks in Charter terms; and even if they somehow could, there cannot an "armed conflict" in legal terms against a transnational non-state armed group (including terrorist organizations, though this raises a number of separate legal questions), giving recourse to the laws of armed conflict, including their permissions and limitations. The US view? For these purposes, there can be in principle and currently is an armed conflict under the terms set out in the AUMF; the existence of an armed conflict triggers the law of armed conflict, which displaces (with perhaps some exceptions) international human rights law; and in any case, the US does not accept that the key international human rights treaty, the International Convention on Civil and Political Rights, applies to its extraterritorial conduct, including the conduct of hostilities. And so the arguments go, on and on. But they start from legal positions that very often amount to ships passing in the night.
Trapp's paper considers the legal arguments offered by the Charter's framing language and the conjunction of Articles 2(4) and 51, observing that, on cursory examination, the
logic of the UN Charter might suggest that an armed attack to which states can respond with defensive force in reliance on Article 51 must be attributable to a state. This is because Article 2(4) of the UN Charter prohibits the threat or use of force against the territorial integrity or political independence of any state. Using defensive force against the base of operations of NSAs within a foreign host state’s territory, even if that defensive force only targets the NSAs who have launched an attack, still amounts to a violation of the host state’s territorial integrity. If Article 51 is to be a true exception to the prohibition on the use of force as set forth in Article 2(4) ... it should respond in some way to the violation of the host state’s territorial integrity. The legal mechanism which has traditionally been relied on to preserve an inter-state reading of Article 51, yet accommodate the need to respond to attacks by NSAs, is that of attribution.
Attribution has been insisted on by the International Court of Justice in its decisions in the Nicaragua, Palestinian Wall, and DRC v Uganda cases; Trapp discusses the ICJ's jurisprudence in some detail. But the problem with insisting that self-defense is only triggered if the non-state actor's actions are "attributable" to a state is, as Trapp candidly states, that this "fails to account for recent uses of defensive force in response to attacks carried out by NSAs" that were not attributable to the host state. In addition, she adds, a "definition of ‘armed attack’ that is limited to state-attributable force fails to respond to the security concerns of states which may be the victim of un-attributable armed attacks."
The divergence of state practice from the ICJ's decisions has not gone unnoticed, of course. But what makes Trapp's paper particularly interesting is its effort, in a short space, to offer an alternative framework beyond that of attribution (particularly as embraced by the ICJ) that "preserves an inter-state reading of Article 51, consistent with the logic of the UN Charter, but which accommodates the security needs of states to defend themselves against armed attacks by NSAs."