Locating the Legal Basis for Detention in Non-International Armed Conflicts: A Rejoinder to Aurel Sari

Last month, in response to the decision of the English High Court in Serdar Mohammed v. Ministry of Defence (see Marko’s commentary here), we wrote a piece arguing that Mr Justice Leggatt correctly concluded that international humanitarian law (IHL) does not provide a legal basis to detain in non-international armed conflicts (NIACs). We argued (contrary to Kubo Macak) that authorization to detain in a NIAC does not come from IHL, but rather must be found either in domestic law or in other branches of international law. In particular, we explained that the fact that IHL applicable in NIACs recognises that detention will occur and regulates such detention does not mean that this body of law provides an authority to detain in NIACs. Locating the legal basis for detention has significant implications for assessing the legality of detention in a NIAC, under international human rights law (IHRL). Aurel Sari has written an articulate and thought-provoking response to our post. We wish here to respond to the key points of Aurel’s critique of our view.

The Distinction between IAC Law and NIAC Law

Aurel begins by responding to our claim that the regulation of internment by IHL does not necessarily lead to the conclusion that IHL authorises it. However, his main criticism ignores the distinction we draw between the law applicable in NIACs and that applicable in IACs. He argues that to ‘conclude that IHL does not authorize any of the activities it regulates takes the argument too far.’ We agree, and in fact we do not make such a claim. Rather, we consider this issue to reflect one of the key differences between the law of international armed conflicts (IACs) and that of NIACs. As we noted in our post, whereas IHL applicable in IACS specifically authorises combatants to engage in hostilities (Art 43(2) Additional Protocol I) and to intern combatants (Art 21(1) Geneva Convention III) and civilians (Arts 27(4), 42-3 and 78 Geneva Convention IV), in NIACs IHL is silent on all of these issues and instead merely regulates certain aspects of them.

The reason for this difference between the two bodies of law is partly a consequence of the context of the two types of armed conflict. Since IACs concern two or more states, one state or the other is going to be acting on the territory of a foreign state and acting with respect to individuals who are foreign nationals.  In these circumstances, only an explicit norm of international law can provide the legal authority for targeting, detention, etc. Without such a rule of international law, these actions would be unlawful as a matter of international law since states do not have authority to take such action on the territory of another state and have obligations to other states with respect to how they treat nationals of those other states.

However, the position in NIACs is very different since such conflicts relate (mainly) to intra-state, as opposed to inter-state, relations. Not only does this mean that, ordinarily, the rights of other states will not be engaged in such situations, but the intra-state nature of NIACs means that there is a pre-existing legal system fully applicable to the situation on which we can fall back, i.e. domestic law.  Unlike the position in IACs, IHL does not need to provide any authorizations with respect to detention in NIACs. As Gabor Rona has stated ‘[i]t is logical that … since there is no conflict between two or more sovereigns [in a NIAC], the IHL of non-international armed conflict should be silent, in deference to national law, on questions of detention’ (Rona (2007) 10 Ybk IHL 232, 241).

Our claim is not, therefore, that IHL contains no authorisations. Rather, our argument is that, whilst the law of IAC contains both authorisations and prohibitions, the law of NIAC, at least in this respect, contains only prohibitions, leaving national law (and, exceptionally, other branches of international law) to authorise state action. As Sandesh Sivakumaran has stated, ‘the law of non-international armed conflict does not provide the parties to the conflict with a right to undertake certain actions. Rather, it prohibits certain actions and regulates other conduct should the parties choose to engage in particular endeavours’ (The Law of Non-International Armed Conflict (OUP, 2012), p 71).

Lack of Prohibitions and Authorizations

Aurel’s next argument is that it makes no sense for the law of NIAC to prohibit the targeting of civilians if it does not at the same time explicitly authorise the targeting of non-civilians (however one may define that category, e.g., as those performing a ‘continuous combat function’, according to the ICRC’s Guidance on Direct Participation in Hostilities). Therefore, so the argument goes, the law of NIAC does contain certain authorisations. We disagree.

There is no contradiction in saying that IHL prohibits the targeting of civilians but does not explicitly authorise the targeting of non-civilians. In so doing, all IHL establishes is that it is prohibited under IHL to target civilians, but it is not prohibited under IHL to target non-civilians. As we pointed out in our previous post, there is a distinction between authorising and not prohibiting conduct in international law.

The temptation to say that IHL does not simply not prohibit targeting of non-civilians but actually authorises such actions is no doubt influenced by the interaction between IHL and IHRL in this area – if IHL explicitly authorises such targeting, it is easier then to say that that authorisation operates as the lex specialis relative to applicable norms of IHRL. But it is important to keep these two issues separate. The question with which we are dealing here is whether IHL contains a legal basis for certain actions (in particular, detention) in NIACs. Its interaction with other applicable rules of international law (including IHRL) is a separate, secondary question. Aurel appears to conflate these issues, and he develops his argument further by claiming that, were IHL to contain only prohibitive rules, ‘the entire debate about the relationship between IHL and international human rights law (IHRL) [would be rendered] superfluous. If IHL were to consist solely of constraints and fail to provide legal authorizations, as Lawrence and Dapo submit, then no conflict would ever arise between these two branches of international law: States would simply have to follow the more restrictive rules.’ We do not think that this follows. Aurel seems to imply that one is excluded from considering any possible interaction between IHL and IHRL unless one can point to a genuine norm conflict, in the sense that IHRL explicitly prohibits action for which IHL provides an explicit legal basis. We do not share this view. Indeed, the ICJ’s Nuclear Weapons opinion, to which Aurel refers, also does not support this view. In that case, the Court applied the lex specialis principle to the relationship between the human right not arbitrarily to be deprived of one’s life and the IHL rules on the conduct of hostilities. Its conclusion, as Aurel quotes, was that the ‘test of what is an arbitrary deprivation of life … falls to be determined by the applicable lex specialis, namely, the law applicable in armed conflict which is designed to regulate the conduct of hostilities’ (para 25). At no point did the Court claim that there had to be an explicit conflict between IHL and IHRL for the lex specialis principle to apply. Indeed, there was no such conflict here. The arbitrariness standard in IHRL does not prima facie prohibit the targeting of combatants (it is true that human rights treaty bodies have interpreted it as effectively doing this, but the treaty itself does not). The Court did not make reference to the lex specialis principle because IHL specifically authorises targeting of combatants in IACs. Rather, the Court simply stated that the notion of arbitrariness is context-specific and, in an armed conflict, may be determined with reference to those rules that have been developed specifically for that situation (whether permissive or prohibitive). To say that one can only take IHL into account to interpret IHRL where there is a genuine norm conflict between the two is not, therefore, consistent with the ICJ’s jurisprudence here.

Equal Application of IHL to States and Non-State Armed Groups

Aurel further takes issue with our view that it is understandable why the law of NIAC does not contain a legal basis to detain, for such a legal basis would apply equally to the non-state armed groups party to the NIAC, which states clearly would not want. He claims that, ‘if the principle [of equality of rights and duties] demands that belligerents enjoy the same status and rights, and common Article 3 does not confer the full panoply of belligerent status and rights on non-State actors, then the only logical conclusion is that the parties to the Geneva Conventions and Additional Protocol II gave up their status and rights as States and assumed the same status and rights as non-State actors.’ This is not true. In adopting CA3 and APII, states certainly did not relinquish any rights they otherwise had, thereby putting themselves on the same level as non-state armed groups. Rather, the very fact that IHL applies equally to both states and non-state groups and does not contain permissive rules protects the pre-existing right of states to adopt national laws that legitimise their actions and criminalise armed group actions.

IHL does not equalise the parties to an armed conflict nor does IHL mean that the parties have equal rights, duties and powers in general. The relevant principle is that IHL applies equally to all parties to an armed conflict. This means that these parties have the same rights and duties under IHL.

Domestic Law and the Authority to Detain in Armed Conflict

Finally, Aurel argues that our claim that states can rely on domestic law to authorise detention in NIACs ignores Art 27 VCLT and suggests that you can use your domestic law to justify breaches of international obligations. We are of course not suggesting that domestic law can be used to justify breaches of treaty obligations. As we noted in our previous post, the majority of human rights treaties do not prohibit internment. Rather they prohibit unlawful or arbitrary internment – they require a legal basis for internment, which can be found in domestic law, and that legal basis must be non-arbitrary (which has been interpreted as involving considerations of reasonableness, predictability, proportionality, etc). The one human rights treaty that does not leave any room for internment is the ECHR, but states can still derogate from Art 5(1) so as to enable them to adopt an internment regime under their domestic law (see, e.g., Ireland v UK).

Locating the Source of any IHL Authority to Detain

A final point about the source of any such legal basis for detention in NIACs deserves a little mention, as it can be forgotten in all this that one still needs to point to a particular source of law for such a legal basis to exist (just because one thinks it might be useful for such a source to exist does not of course mean that it does). A lot of the discussion has considered an implied legal basis to detain in the treaty provisions recognising that detention occurs in NIACs. As we have said, this proves nothing as there are plenty of examples in international law where something is recognised and regulated but not legalised. There have also been suggestions that custom contains such a legal basis. To demonstrate that a legal basis for detention exists in any of these sources requires support from practice and opinio iuris (the latter at least in the case of custom). States of course detain all the time in NIACs, but all this proves is that IHL does not prohibit such detention. What is more illuminating here is on what basis states justify that detention, because whilst the UK’s claims in Mohammed supports an opinio iuris in favour of the legal basis being based in IHL, most state practice in this area looks elsewhere. As noted in our previous post, states tend to rely on domestic law or even Security Council Resolutions (again, see the UK in Al-Jedda). Even in the Copenhagen Principles on the Handling of Detainees (which are said to apply in extra-territorial NIACs and peace operations), it was stated that the legal basis for detention could exist in domestic law, UN resolutions, etc, but no claim was made that, in the context of NIACs, there exists an implicit legal basis to detain under IHL. That IHL should provide such a basis as a matter of logic (with which one may or may not agree) cannot make up for this lack of supporting practice.