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

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Over at Just Security (see for example herehere 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.

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Kai Ambos says

October 18, 2016

Dear Dapo

Thanks for this important post. I have a few queries though, here is the most important one re your fourth point: while Art 8 ICC Statute maintains the two box approach it largely assimilates - in line with Tadic - IAC and NIAC crimes so I think it is an overstatement when you say the crimes are "very" different. The problem is that the drafters have adopted IHL language and that creates some confusion. Take for example the killing of civilians which is either "wilful killing" (Art. 8(2)(a)(i) = IAC) or - less precisely - "violence to life and person" (Art. 8(2)(c)(i) = NIAC). Also, attacks on civilian objects are - contrary to your somewhat apodictic assertion - punishable in a NIAC according to Art.8(2)(e)(iv) and - more specifically- according to Art.8(2)(e)(ii) and (iii). Last but not least, I would also argue that disproportionate attacks are punishable in a NIAC since the principle of proportionality is of customary nature and as such also applicable in a NIAC.

Dapo Akande says

October 18, 2016

Dear Kai,

Many thanks for your comment. I agree that the there is significant overlap between the two list of war crimes - for IACs and NIACs - in the ICC Statute but there are still important differences. You are of course right that some attacks against civilian objects in NIACs are within the jurisdiction of the ICC but in those cases it is because the objects qualify for some more specialised protection. The provisions you refer to Art. 8(2)(e) (ii), (iii) and (iv) deal only with those cases of more specialised protection (objects using the distinctive emblems of the Geneva Conventions in conformity with international law; those involved in humanitarian assistance or peacekeeping missions; and buildings dedicated to religion, education art, science or charitable purposes medical establishments etc). There is no general jurisdiction over attacks against civilian objects in NIACs under the ICC Statute as there is for IACs.

You may well be right that disproportionate attacks are punishable in a NIAC under customary international law but that would not give the ICC jurisdiction over that crime as there is no such prohibition in the Statute with respect to NIACs.

Aliki says

October 18, 2016

First of all, I would like to thank you for this insightful post.

Second, I would have a question with regard to detention. Given that the scenario of mixed conflicts is asserted, then the classification would not have to be done for each pair, and split the conflict into each components? And if this is the case, then the US with Syria would be an IAC and thus the IAC detention requirements would apply for the capture of Syrian forces. But with regard to ISIL, would it not be a NIAC and thus detention evaluated under NIAC provisions?

Thank you very much in advance.

Dapo Akande says

October 18, 2016

Dear Aliki,

Your question is a very good one and an important one. My view, as I expressed in the chapter of mine that I refer to in the post is that in this sort of scenario the IAC and the NIAC would in many respects be inseparable. I said then that "the conflict with the non-state group will be so bound up with the international armed conflict between the two states that it will be impossible to separate the two conflicts." (p. 77 in Wilmhurst (ed), International Law and the Classification of Conflicts ). In other words, act that constitute part of the NIAC, would also be part of the IAC. Picking people up from Syrian territory and detaining them in the context of a use of force against Syria (i.e on its territory and without its consent) is part of that conflict, even if the motivation or reason for doing so is because of a conflict with ISIL or some other group. Those persons picked up in Syria are arguably protected persons within the meaning of GCIV and it is precisely the purpose of the procedural guarantees in GCIV that when a state is detaining persons, on security grounds, from the other state (or who otherwise qualifies under GCIV) it has to show using the prescribed procedures that it is absolutely necessary to detain these people. The mere fact that the state asserts that the person picked is part of some other NIAC cannot defeat that purpose of GCIV. Think of the case of an occupation by one state of the territory of another but where you can also have a NIAC with a non-state group in the occupied territory that is not under the control of the state being occupied. The provisions on occupation in GCIV do not cease to apply just because there is also a NIAC with a non-state group. Those two conflicts are inseparable and the IAC law does not cease to apply because there is also a NIAC.

Eliav Lieblich says

October 18, 2016

Hi Dapo,

Fascinating and helpful as always. Let me add additional differences. If it is an IAC, this might mean that the territorial state is obliged to take positive protective steps even if it is not directly party to the fighting. For instance, it must take precautions against the effects of attacks in order to safeguard its civilians throughout its territory (namely art 58 API). I'm not sure this is a customary obligation in NIAC if the territorial state is *not* a party. Furthermore, there is the issue of the duty to allow humanitarian access which might be different if the conflict becomes an IAC (art. 70).


Aliki says

October 18, 2016

Thank you very much for your detailed reply and references. Indeed I see the complexity and the different outcomes depending on whether one focuses on the international component (a State use of force against another State) or the "personal" requirement in the sense of the wording of CA2 "between two or more of the High Contracting Parties" - and whether the emphasis on the former could be also considered a way to expand the applicability of the IAC framework. Some issues for further reflection - and again thank you for highlighting the implications that follow each type.

Dan Joyner says

October 18, 2016

Lucid and persuasive, as always.

Max Brookman-Byrne says

October 18, 2016

Dear Dapo,

Thanks for a great post--I find that I am more and more coming around to your way of thinking, having previously been certain that a use of force without the consent of a territorial state would not result in an automatic IAC! I'm most persuaded by your brief mention of the doctrinal distinction between jus ad bellum and international humanitarian law, and the fact that determinations under one do not result in consequent determinations under the other (that is to say legality under JAB does not affect the existence or not of an armed conflict under IHL and vice versa). So anyway, thanks, first of all, for that!

My question is this: what are your initial thoughts about the alleged presence of Turkish troops in the current operation against ISIL in Mosul? Iraq has not consented but Turkey has stated that it must be involved in the conflict. Nevertheless, Iraq has consented to the general operation against ISIL. To my mind, based on your suggestion, this means there is a NIAC between the coalition (including Turkey) and ISIL, and an IAC between Iraq and Turkey. In your opinion, is this an instance in which the NIAC and IAC are less imbricated? Or do you think that any instance of such a mixed conflict will always been necessarily inseparable? Will it be the case that ISIL members detained by Turkish troops will be governed by the law of IAC while those picked up by other members of the coalition will be subject to the law of NIAC?

Thanks again,

Dapo Akande says

October 19, 2016

Dear Max,

My view is that in the scenario you describe there would indeed be this difference between those members of ISIL picked up by Turkey and those picked by Iraqi forces, forces of those states that Iraq has given consent to, or by other organized armed groups. This might at first sight seem anomalous but actually it isn't and respects the logic of the differentiation between the law that regulates IACs and that which regulate NIACS. The reason for the more limited regulation of NIACs is that states had what might be described as "sovereignty concerns" with regard to regulation of how they treated people within their territory. They were willing to accept some regulation but not willing to go as far as the regulation for IACs - hence the decision to have a much more watered APII as compared to API. However, those "sovereignty concerns" do not apply when a state is acting abroad on the territory of another state. So Iraq and those that Iraq has given consent to operate on its territory have more freedom as to how they treat people they detain in Iraqi territory than Turkey which can hardly insist on a freedom as to how it treats people that it picks up within foreign territory - even if Turkey were able to make a valid jus ad bellum case for its military action.