When one state, say, the United States, uses military force on the territory of another state, say, Syria or Pakistan, without the consent of that state, what legal rules constrain that use of military force? What if the attacking state does not target the armed forces or institutions of the other state but instead targets an organized armed group (say, ISIL or the Taliban) operating in the other state?
According to the International Committee of the Red Cross (ICRC) 2016 Commentary on the First Geneva Convention, if one state uses military force on the territory of another state then the use of force triggers an international armed conflict (IAC) between the two states, unless the territorial state consents to the use of force. Accordingly, the law of IAC applies to, and constrains, all such uses of force.
Importantly, the law of IAC applies even if the intervening state exclusively targets an organized armed group operating in the territorial state. If there is a non-international armed conflict (NIAC) between the intervening state and the armed group then the law of NIAC may apply in parallel.
The ICRC’s position has attracted substantial criticism, including on Just Security (see here, here, and here). I hope to respond to some of these criticisms in a future post. For now, I will try to explain why I find the ICRC’s view persuasive. This post, like my previous one, emerged from a terrific recent event at the University of Georgia School of Law that examined a number of issues raised by the Commentary.
Before we begin, let’s remember why the question is worth asking, and why the answer matters. Conflict classification can seem dry and technical, but it affects both protection and accountability in armed conflict.
First, the treaty law of IAC is far more detailed and robust than the treaty law of NIAC. Most importantly, the Geneva Conventions and Additional Protocol I are far more protective of both civilians and combatants than either Common Article 3 or (with respect to internal conflict) Additional Protocol II.
Second, the customary law of IAC remains distinct from the customary law of NIAC, though the gap has certainly narrowed since the 1990s. For its part, the ICRC identifies 23 customary rules applicable in IAC but not in NIAC. States that take a more conservative approach to customary international law may conclude that the gap between IAC and NIAC remains even wider than the ICRC maintains.
Finally, the Statute of the International Criminal Court recognizes 34 war crimes in IAC but only 19 war crimes in NIAC. Notably, the Statute recognizes knowing violation of the proportionality rule as a war crime when committed in IAC but not when committed in NIAC.
To fix ideas, consider the following scenario:
No Consent: State A launches an airstrike against organized armed group G on the territory of State T, foreseeably killing several civilians. State T exercises no control over group G, but also does not consent to State A’s strike.
According to the Commentary, State A’s strike triggers an IAC with State T to which the law of IAC applies. If there is, in addition, a NIAC between State A and group G then these two conflicts occur in parallel.
(Note that conflict classification does not depend on the lawfulness of State A’s attack under the jus ad bellum. For these purposes, it does not matter whether State A is lawfully defending itself against an armed attack by group G or unlawfully using military force to eliminate a possible future threat.)
In my view, the ICRC’s position fully reflects the text, object, and purpose of the Geneva Conventions and their Additional Protocols. An international armed conflict is a dispute (‘conflict’) between states (‘international’) involving the use of military force (‘armed’). It is hard to imagine a more serious dispute between states than a dispute regarding the use of military force by one on the territory of the other.
Indeed, States adopted the law of IAC in order to protect their civilians and armed forces from extraterritorial force by foreign states. States using force beyond their borders may not recognize many legal, ethical, or political constraints on their conduct. Accordingly, when State A uses force on the territory of State T, we need the law of IAC to protect the civilian population of State T from the military operations of State A and (as we shall see) to protect the armed forces of State A from criminal prosecution by State T.
In contrast, States adopted the law of NIAC primarily to regulate internal armed conflicts within their own territory. States using force on their own territory may feel constrained by domestic law, human rights law, concern for their own citizens, and internal politics. Accordingly, the need for robust protection by the law of armed conflict may have seemed less urgent.
The alternative view—that no IAC exists and that the law of IAC does not apply—seems deeply implausible.
First, the law of NIAC may not apply either. On the prevailing view, including that of the ICRC, the law of NIAC applies only to protracted armed confrontations between state armed forces and organized armed groups or between such groups. If group G is not organized in the right way, or if fighting between State A and group G is not sufficiently intense, then a gap in protection would exist that no state would accept. (As Just Security readers know, I partially reject the prevailing view and partially disagree with the ICRC on this point.)
Second, it is hard to believe that states would want legal protection for their civilians from foreign forces to depend on what those foreign forces choose to target. If an intervening state targets the armed forces of the territorial state then civilians may receive robust protection under Additional Protocol I. In contrast, if an intervening state targets an organized armed group then civilians may receive only the minimal protections of Common Article 3 (which, arguably, does not regulate the conduct of hostilities at all). Defenders of the alternative view must explain why states would accept such limited protection for their civilians from foreign forces in such cases.
Third, in internal NIACs, states may be constrained in their treatment of their citizens by human rights law and by domestic law. In contrast, in cross-border cases, IHL is the primary (though not exclusive) constraint on the intervening state’s conduct. Accordingly, in cross-border cases, we should not rely on the law of NIAC to provide civilians with the level of protection envisioned by the parties to the Geneva Conventions and Protocols.
In my view, the customary law of NIAC now offers civilians protection comparable to that offered by the customary law of IAC. However, in my view, we should interpret Common Articles 2 and 3 of the Geneva Conventions in light of the customary law of NIAC as it existed when those treaties were adopted and entered into force. At that time, no state would have relied on the customary law of NIAC to protect their civilians from foreign states operating on their territory without their consent.
Fourth, the alternative view exposes the forces of the intervening state to criminal prosecution by the territorial state. There is no combatant immunity in NIAC and, on the alternative view, there is no IAC. It follows that, if State T captures State A’s pilot, then State T may prosecute the pilot for killing its civilians under State T’s domestic criminal law even if the strike did not violate the targeting rules of the customary law of NIAC.
In my view, State T’s capture of the pilot may itself trigger an IAC between the two states, such that the law of IAC would regulate his detention. However, the strike occurred prior to capture and therefore, on the alternative view, before an IAC began. Hence, the pilot would not be entitled to combatant immunity with respect to the strike. Since combatant immunity exists to protect combatants from prosecution by foreign states for acts that do not violate the law of armed conflict, it is hard to see why states would deny their own forces such protection in such cases.
Finally, the alternative view seems ad hoc. If one state uses military force against anything else in another state—citizens, state armed forces, or foreign visitors, private property, state institutions, or refugee camps—then it seem clear that an IAC exists and that the law of IAC applies. Defenders of the alternative view must justify carving out an exception to this general rule for strikes directed at armed groups. Given the evident need to protect civilians from the intervening state, and to protect captured combatants from the territorial state, such a justification seems hard to imagine.
For these reasons, I favor the ICRC’s position over the alternative view. The use of force by one state on the territory of another should be constrained by the law of IAC, even if that force targets an organized armed group on that territory, unless the territorial state consents to that use of force. As mentioned earlier, the ICRC’s position has attracted criticism, some of which I hope to address in a future post.