When Does the Use of Force Against a Non-State Armed Group trigger an International Armed Conflict and Why does this Matter?

Over at Just Security (see for example here, here and here) and also at Opinio Juris (see here and here) there has been a very interesting discussion on whether aspects of the conflict in Syria should be regarded as international armed conflicts (IACs) rather than simply non-international armed conflicts (NIACs). These discussions have followed on from the release of the ICRC’s revised Commentary to the First Geneva Convention (GCI) of 1949 in which the ICRC, in its commentary to Common Article 2 dealing with international armed conflicts (one between the High Contracting Parties to the GCs), states that where a state uses force against a non-state group on the territory of another state without the consent of the territorial state it would amount to an international armed conflict between the intervening state and the territorial state. So as Adil Haque pointed out on EJIL:Talk! in April, the ICRC position would mean that the US (and other states using force in Syria without the consent of the Syrian government) is involved in an IAC in Syria. Adil has explained his support for the ICRC position in posts on this issue on Just Security (see here and  here). Others like Terry Gill, Sean Watts and Kenneth Watkin have disagreed (see here, here, here, and here).

I am on record as being a supporter of the position that the ICRC has now come to. I wrote a piece (available here on SSRN) many years ago, which was part of a major study on Classification of Conflicts in which I say precisely what the ICRC has now said (and I’m delighted that the ICRC’s revised commentary cites that work). I am not going to repeat my arguments in this post and they can be found here. In summary, my view is that an international armed conflict is a conflict between states, and a conflict arises between states when one state uses force against another state. What does it mean for a use of force to be against another state? It means simply that the force is used on the territory of the other state without its consent. Note that this says nothing about whether that use of force is lawful or unlawful under the jus ad bellum. Such non-consensual uses of force may or may not be lawful under that body of law, and the application of IHL remains independent of the legality of the use of force under the jus ad bellum. It is also important to remember that saying that there an IAC between the two states says nothing about whether there is a NIAC between the state using force and the non-state group. There will, in many cases, be such a NIAC. This will raise questions about the relationship between the two conflicts: the IAC and the NIAC. However, the notion of mixed conflicts is by no means unusual or confined to this context. In the Nicaragua case the ICJ noted that it was addressing a situation where there was an IAC and a NIAC. The same was also true with regard to the conflicts in the former Yugoslavia or before that in Vietnam, which were also mixed.

In this post I wish to concentrate on why it might matter whether a use of force directed at a non-state actor on the territory of a non-consenting state is an IAC or a NIAC. What exactly would turn on this question. Here I provide a general response to that question rather than one directed particularly at answering the question (which has been the subject of some of the commentary on Just Security and Opinio Juris) of what would turn on whether the US is involved in an IAC in Syria. Some of the points below would be relevant for the US in that particular conflict, others might not be.

Here are a few reasons why it might make a difference whether a state using force on the territory of another without  the consent of the other is involved in an IAC (in addition to a NIAC, if one already exists). Some of my points repeat a comment I made in response to Adil Haque’s EJIL:Talk post of  April of this year and readers might wish to view the discussion in response to that post.

– First, with regard to the rules relating to the conduct of hostilities, though there is much convergence of the law relating to IACs and that relating to NIACs  there is not total convergence. Some differences remain, for example, in the rules relating to the protection of the natural environment. So in the course of targeting a non-state group, if the conflict brings into play IAC law, then the state using force is bound to respect those rules like Art. 35(3) and 55(1) of API, which are more restrictive than the rules that apply in a NIAC. If the state uses force wishes, for example, to take measures to affect the natural environment because the non-state group is based in a forested region, its options would be more limited if we consider that there is an IAC as opposed to merely a NIAC.

– Second, with respect to detention, the law of IAC contains significant differences from the law of NIAC. If the state using force occasionally sends forces in to pick up people from the state where the non-state group is based (as the US has done in Syria) and then takes them back to its own territory for detention then it matters whether IAC law or NIAC law applies. If there is an IAC between the state where the person is picked up and the state that is using force then the Fourth Geneva Convention (GCIV) applies and the detention regime of GCIV applies with regard to internment of civilians within the territory of a party to the conflict. Questions of course arise as to who is protected by GCIV, and whether the provisions of that Convention extend to persons who have engaged in hostilities but who do not benefit from the protections of GCIII. However, that is a separate question from whether GCIV applies at all. [And the ICRC and many take the view that all those who do not benefit from GCI, II or III are entitled to the protections of GCIV unless there is a “derogation” from GCIV under Art. 5 of that Convention (see for example here)].

This question of the detention regime that would apply is very significant indeed, in cases where the state using force also engages in detention operations. Completely different legal regimes would apply depending on whether we think there is an IAC or not. Or to be more precise, if there is an IAC the IHL procedural regime of detention kicks in, if there is only a NIAC, IHL will have little to say about who can be detained, for how long, or what standards of review are available.

Also whether there is an IAC or not also has implications for the application of international human rights law with regard to detention. In Hassan v UK, the European Court of Human Rights held that if there is an IAC, this would provide a legal basis for detention, for the purposes of human rights law (see here, and here). If it is only a NIAC, the legal basis for detention, for the purposes of satisfying human rights law, would need to be found elsewhere (as the English Court of Appeal held in the Serdar Mohammed case) see (here, here and here) . Also if there is an IAC there is the possibility (as was suggested in Hassan v UK by the ECtHR) of reading the IHRL review standards through the lens of IHL. It is not clear that the Court would do this if the conflict is only a NIAC.

– Third, with regard to prosecutions,  combatant immunity applies in IACs. So if a US or UK personnel somehow came to be arrested in Syria by the Syrian government, and the conflict is an IAC then they may not be prosecuted merely for taking part and would have to be accorded prisoner of war status.  However, there does not seem to be any practice that suggests that combatant immunity applies also in a NIAC, even an extraterritorial one. If there were such immunity in NIACs questions would arise as to whether it applies also to the non-state side. There is clearly practice that denies such immunity to non-state groups. So to accept combatant immunity in NIACs would be to create an exception to the rule regarding equal application of IHL. If the Syrian conflict did not involve an IAC then the US or UK personnel that came to be arrested by the Syrian government could lawfully be put ion trial without the benefit of combatants immunity.

There is an interesting question as to whether the ordinary immunity that foreign state officials are entitled to would apply with respect to actions taken by state forces on the territory of another state in a NIAC. However, there is a view that this immunity does not extend to acts on the territory of the forum state done without the consent of the forum. That view was adopted by English Divisional Court in the Khurts Bats case and recently adopted by present ILC Rapporteur Concepción Escobar Hernández in her Fifth report on immunity of State officials from foreign criminal jurisdiction released this summer (paras. 225-229). TIf this view, which was also taken by the former ILC Rapporteur Kolodkin, is correct then ordinary immunity would not apply in our scenario.

Fourth, and also relating to prosecutions, there is the question of ICC jurisdiction (something not relevant to US in Syria but relevant to France, UK and others in Syria). The list of war crimes subject to ICC jurisdiction is very different depending on whether the conflict is an IAC or NIAC. So whether action of a party to the Rome Statute in Syria or elsewhere is part of an IAC or NIAC is important for working out what crimes the ICC might be able to investigate or prosecute for.

In this context, it is important to recall that the targeting of civilian objects is not a war crime under the ICC Statute in a NIAC nor is targeting in breach of the principle of proportionality. The ICC only has jurisdiction over those crimes when committed in IACs. There have been discussions about targeting of war sustaining objects in Syria and whether these objects are legitimate military targets (see here and here). If they are not military objectives they would be civilian objects and targeting them would be a war crime. It is important to note that some of these objects, eg oil installations under the control of ISIS were previously under the control of the Syrian government and probably are property of the Syrian government.

Fifth, and again relating to prosecutions , there is obligatory universal jurisdiction with regard to grave breaches of the Geneva Conventions and Additional Protocol I. The grave breaches regime only applies in IACs.

Sixth and related to the point on universal jurisdiction , the argument that there is no immunity for state officials who commit international crimes is strongest in cases where there is a treaty which sets out the crime, applies it to state officials and requires other states to prosecute [the argument used by the English House of Lords in the Pinochet case]. As Sangeeta Shah and I have pointed out, the Pinochet argument, by which I mean, the narrow argument that in some cases there is conflict between the prior customary rule according immunity and more recent treaties permitting the exercise of foreign jurisdiction over state officials is equally  applicable to grave breaches provisions of the GCs.  So whatever else we may think of immunity for international crimes, it seems hard to maintain immunity in cases covered by grave breaches provisions in an IAC. My own view is that there is no immunity also with respect to international crimes in NIACs but not everyone is persuaded by that.

These are all issues that will depend on whether there is an IAC when a state uses force on the territory of another state without the consent of another state. Not all of these issues will arise in any particular conflict and not all arise in Syria. However, the list indicates that the question of classification remains important.