Self-defense Operations Against Armed Groups and the Jus in Bello

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The Paris shootings and France’s reaction have once again triggered debate on states’ right to self-defense against attacks by non-state actors (see here, here, or here). Discussions normally focus on jus ad bellum issues, such as the ‘unwilling or unable’ test or when a threat is imminent. A question that receives strikingly little attention is whether the invocation of the right to self-defense against a non-state armed group under jus ad bellum would provide a sufficient legal basis for attacking this group by military means. As Marko Milanovic pointed out on this blog, the lawfulness of strikes against a non-state entity does not only depend on jus ad bellum but also on a second layer of legal examination: does the attack form part of an armed conflict and complies with international humanitarian law, or is the attack in questioned governed by international human rights law and possibly infringes on the targeted person’s right to life? This post examines how the use of military force in self-defense against non-state armed groups may be justified under jus in bello.

France’s president Hollande has made it clear that he considered the Paris attacks an ‘acte de guerre’ and that France is now engaged in a war against terrorism. Political rhetoric aside, what he probably meant is that he considers France to be engaged in an armed conflict with Daesh. As Daesh is a non-state entity, this conflict must be non-international. For international lawyers, he seemed to state the obvious. Reportedly, France joined the US-lead anti-Daesh coalition in 2014. This coalition initially supported the Iraqi government in its non-international armed conflict (NIAC) against Daesh. When France expanded its airstrikes from Iraqi into Syrian territory in August 2015, this could probably be considered part of a spillover of the conflict that commenced in Iraq. As France’s recent attacks against Daesh form part of the same conflict, IHL applies to them and such attacks appear lawful as long as they comply with applicable IHL.

Nonetheless, the increasing involvement of states in ‘self-defense’ operations against non-state actors sparks the question of under which conditions this use of force falls under the scope of IHL? Only in that case could aerial bombardments against military targets be lawful.

Following the seminal Tadic formula, a NIAC exists if there is ‘protracted armed violence between governmental authorities and organized armed groups or between such groups’. The ‘protracted armed violence’ requirement has been interpreted as ‘referring more to the intensity of the armed violence than to its duration’ (ICTY, Haradinaj et al, 2008, para. 49). This suggests that the NIAC threshold could be met relatively quickly if sufficiently intense violence occurs between the parties. Yet, a NIAC requires more than isolated or sporadic acts of violence, meaning that even intense isolated acts of violence, such as aerial bombardments or a terrorist attack, can barely trigger an NIAC instantly. Rather, at least to my mind, traditionally the laws of NIAC apply in situations where armed violenec between state forces and armed groups, or between armed groups, escalates into sufficiently intense hostilities. Concretely, Belgium could not launch airstrikes against an armed group based in infamous Molenbeek if that group succeeded in launching one attack in Brussels.

Over the past years, however, it seems that states simply decided to launch attacks against ‘terrorist organizations’ extraterritorially in alleged self-defense and immediately proceeded with airstrikes. To assess whether such conduct may fall under jus in bello, three situations must be distinguished. (nota bene: in addition to the issue discussed here, the question of whether the concept of NIAC encompasses situations in which one party bombs the other party but the latter is hardly ever shooting back would warrant some thought.)

First, if states are already involved in a NIAC with the armed group, they may decide to increase their strikes as part of the same conflict (possibly the case of France above).

Second, states may join an on-going NIAC in support of one of the conflicting parties. With regard to such situations, the ICRC has suggested that under certain circumstances a state can become party to a NIAC even if its conduct does not meet the NIAC intensity threshold by itself. This has been called the ‘support-based approach’, originally developed by Tristan Ferraro. In its recent report on ‘International humanitarian law and the challenges of contemporary armed conflicts’, the ICRC explained:

According to a support-based approach, IHL would apply to multinational forces when the following conditions have been cumulatively met: (1) there is a pre-existing NIAC taking place on the territory in which multinational forces are called on to intervene; (2) actions related to the conduct of hostilities are undertaken by multinational forces in the context of the pre-existing conflict; (3) the military operations of multinational forces are carried out in support (as described above) of a party to the pre-existing conflict; and (4) the action in question is undertaken pursuant to an official decision by the troop-contributing country or the relevant organization to support a party involved in the pre-existing conflict.

This approach was primarily developed to address situations in which, during multinational operations, a state provides support to a party in an on-going NIAC that makes a contribution to the collective conduct of hostilities but does not, in and of itself, render the laws of NIAC applicable between the supporting party and the adversary. In such situations, the supporting state becomes party to the NIAC if its conduct meets the four listed criteria. While this approach helps safeguarding ‘the imperative of not blurring the combatant/civilian distinction’ and ‘maintaining the principle of equality of belligerents’ (Challenges Report, p. 23), it arguably also provides a legal argument on how a state may use force under the rules of IHL without having previously been party to a NIAC. For example, and depending on the facts, when France bombed Daesh for the first time in 2014, it may have done so lawfully in support of Iraq or the US which were already parties to an on-going NIAC with Daesh.

The third situation is where a state uses force against a non-state armed group without being itself party to an on-going NIAC and not in support of another party. Unless one agrees with the controversial concept of a global NIAC against Al Qaida and associated forces, this could have been the case when the US attacked the so-called ‘Khorasan Group’ in Syria in 2014. On the ad bellum side, the US justified these attacks with its right to self-defense (for some discussion, see here or here). While the use of force in self-defense against a state would certainly trigger an international armed conflict, as pointed out above a single strike – be it by a state or a non-state actor – is unlikely to trigger the laws of NIAC. As Noam Lubell argued with regard to a similarly isolated strike by the UK against alleged British Daesh members in Syria, ‘it is hard to see how … [a single airstrike not connected to an on-going NIAC] would pass the intensity threshold to be considered a separate armed conflict’.

Indeed, the idea that a single strike may already form part of a previously non-existing NIAC is not in line with jurisprudence of the ad hoc tribunals, the ICC, or the 2008 opinion of the ICRC. However, may ‘self-defense’ measures against ‘terrorist groups’ lead to a change in the international community’s understanding of the jus in bello threshold on the use of extraterritorial force against non-state actors? As Anne Peters pointed out with regard to a possibly changing interpretation of article 51 UN Charter, ‘silence of the vast majority of states is in normative terms problematic, because it risks to be interpreted as implied acquiescence’ to a re- or misinterpretation of the existing legal standard. Are states increasingly blurring the strict separation of jus in bello and use as bellum by accepting that they may use extraterritorial military force against an imminent threat posed by non-state actors and thereby trigger a NIAC? Andrew Clapham is probably right in cautioning that such a change in the NIAC threshold bears

a risk that this low threshold gets misapplied to determine the existence of a right to use force in self-defence, or the application of the wider law of armed conflict, thus escalating the violence and putting even more people at risk.

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Kriangsak Kittichaisaree says

December 16, 2015

Very interesting article. However, your analysis is based on the presumption that this is a NIAC situation. Can't ISIL be considered a quasi-State and fighting it is an international armed conflict?

Look at the African Union's Non-Aggression and Common Defence Pact of 2005 which recognizes that non-State actors may commit 'aggression' against a State. The Protocol on Non-Aggression and Mutual Defence in the Great Lakes Region of 2006 authorizes each of its States Parties to exercise 'the right of individual or collective self-defence in the event of an armed attack' by an armed group, or the failure by the territorial State from which the armed group operates to intercept and disarm members of the armed group.

It seems that, at least in the AU practice, attacks by non-State actors such as ISIL would be a situation of IAC, not NIAC.

Tilman Rodenhäuser says

December 16, 2015

Dear Kriangsak,
Thanks for your comment!
If Daesh was a state, we would indeed have an IAC. However, as far as I know there is vast agreement in the international community that Daesh is not a state but an – admittedly powerful – non-state entity. There is certainly debate on the question of when such an entity constitutes a state under international law. I guess one reason why other states do not consider Daesh a state is lack of legitimacy. For example, Martti Koskenniemi argued recently that ‘being a state does not only depend of effective control over territory. Being a state depends first and foremost on the legitimacy of a government in a territory’ (my translation, original in German:
For me, the practice you cite concerns jus ad bellum questions, not use in bello ones. And this is the point of my article: even if states may lawfully invoke a right to self-defense against non-state actors under jus ad bellum, this does not automatically mean that their relationship with this non-state entity is governed by jus in bello. However, I guess the question of whether and to what extent the NIAC concept could change in light of current practice on the extraterritorial use of force against non-state actors is legitimate…
Best wishes,

Jordan says

December 16, 2015

ISIS is merely an insurgent that happens to be fighting in an IAC (see 8 Albany Govt. L. Rev. 166, 170 n.7 (2015), available at ). The armed conflict that is ongoing at least in parts of Syria and Iraq is an IAC because several states are directly participating in the armed conflict and a NIAC only occurs "within a single state," etc. (see NIAC Nonsense ...., available at ).
The status of members of the armed forces of states that are directly engaged in the armed conflict is that of combatants, with combatant immunity for lawful acts of war (see, e.g. id.) and that status of fighters for ISIS remains civilian "insurgent" that is DPG or CCF and targetable because they are DPH and CCF under the law of war paradigm (and are DPAA and CAAF under the self- and collective self-defense paradigm. See,e.g. Id.).
Whether or not the European Convention applies to lawful acts under the laws of war (e.g., did a relevant European state derogate under art. 15? And if not, why not?), the ICCPR and the UN Charter (arts. 55(c), 56, and 103) apply globally, but the persons who have human rights protections are those within the effective control of a party to the conflict (either ISIS or, for example, the U.S.). Persons being targeted by drone or aircraft are not within the effective control of the pilot, etc. See also regarding Human Rights on the Battlefield,

Dimitrios Kourtis says

December 18, 2015

Dear Tilman,
Congratulations on your thorough analysis!
I would be most interested in hearing your opinion about the implications (if any) of S/RES/2249 (2015) on the jus in bello / jus ad bellum dichotomy vis-à-vis the operations lauched after the SC's "calling (upon ...)".
I kindly thank you in advance.

Tilman Rodenhäuser says

December 19, 2015

Dear Dimitrios,
Thanks a lot for your comment.
In my view, under the UN Charter the UNSC has a core role in jus ad bellum questions. Hence, a resolution can have an impact on the question of whether air strikes may be justified under jus ad bellum. The UNSC does not have the same authority when it comes to jus in bello questions. It cannot declare a situation a NIAC and render IHL applicable if the criteria for its application are objectively not met. Similarly, the UNSC cannot find that IHL does not apply to certain operations if it objectively applies. If the UNSC calls in resolution 2249 upon states to ‘take all necessary measures’ this does not define which rules apply to the measures (IHL or IHRL). The SC states explicitly that this must be done ‘in compliance with international law’. For me, even if that resolution authorized the use of force (which I doubt), it does not say anything about which laws govern the actual use of force (IHL or IHRL)...
Thus, legally I do not think the resolution has any implication on the ad bellum/in bello dichotomy. The political impact is a different question...
I hope that answers your question!
Best wishes,