1. Introduction
The relationship between international humanitarian law (IHL) and international human rights law (IHRL) has been the subject of a significant amount of scholarly debate.Footnote 1 It has become especially topical in light of the case law of the International Court of Justice (ICJ), confirming the continued applicability of IHRL during armed conflict.Footnote 2 This case law represents an important milestone in a long trend of legal developments that challenged the traditional view that human rights law, as the law of peace, played no role in armed conflict.Footnote 3 As a result, the question of how IHRL is to interact with IHL in such situations is now posed. This raises few problems where the particular issue under consideration is regulated either by just one of the two bodies of law or by both bodies in the same way.Footnote 4 However, for those issues on which the two lay down very different standards – such as detention and the use of lethal force (where IHL is more permissive than IHRL) – one is faced with having to determine how these regimes interact.Footnote 5 Is it possible to reconcile the rules of humanitarian law and human rights law such that both can be applied in parallel? Or must one rule set aside the other? There is judicial support for both of these approaches, and thus the question remains open.Footnote 6
The approach taken in this article is to consider the compatibility of the two bodies of law at the level of principle. To do this, consideration must be given to the object and purpose of each regime. Regarding IHRL, it is generally acknowledged that this seeks to delimit the coercive power of states vis-à-vis individuals within their jurisdiction, as well as lay down certain positive obligations.Footnote 7 The traditional view of IHL, on the other hand, is that it seeks to balance humanitarian considerations with considerations of military necessity; that is, having accepted that war occurs, IHL attempts to humanise it as much as possible.Footnote 8 Based on these conceptions of the underlying purpose of each body of law, commentators often emphasise the principle of humanity as the unifying element.Footnote 9 Theodor Meron, for example, considers humanitarian concerns to constitute the ‘common denominator’ of IHL and IHRL.Footnote 10 Given that both seek, albeit in different ways, to protect individuals, humanity can indeed be seen as a unifying principle. However, by focusing on considerations of humanity, virtually no attention has been paid to the role played by necessity in each body of law.Footnote 11 Indeed, it has been argued that it is the balancing of considerations of military necessity against humanitarian concerns in IHL that differentiates it from human rights law.Footnote 12
It is on this question of the influence of considerations of necessity in IHL and IHRL that this article focuses. In so doing, its goal is two-fold. First, in contrast to conventional accounts of IHL and IHRL, which tend to focus on humanity as the unifying principle, this article will demonstrate that necessity also plays an important role in each body of law, albeit in very different ways. In particular, it will be shown how these different functions of necessity account in large part for certain fundamental differences between IHL and IHRL. Section 2 will begin this discussion with a brief elaboration of the role of necessity in general international law. This will be limited to drawing out those features of necessity that help to elucidate its role in IHL and IHRL so as to frame the discussion in subsequent sections and allow for analogies to be drawn throughout. Sections 3 and 4 will then examine the differing roles played by necessity in IHL and IHRL, respectively, demonstrating how these roles impact on the specific rules in each. The second goal of this article is then to employ this necessity-based analysis in order to develop a principled relationship between a conduct of hostilities and a law enforcement approach to regulating complex conflict situations.Footnote 13 This will be the subject of Section 5, which will draw on the discussions from the previous sections and offer some examples of how the thesis would operate in practice.
2. Necessity in General International Law
In general international law, necessity operates as part of the secondary rules on state responsibility. According to those secondary rules, an internationally wrongful act incurring the responsibility of a state will occur where the particular conduct is attributable to that state and constitutes a breach of its international obligations.Footnote 14 However, in exceptional circumstances, the wrongfulness of such conduct may be precluded, effectively allowing a state to raise a defence to an otherwise wrongful act that would, but for that defence, entail its international responsibility.Footnote 15 It is generally accepted that among those circumstances that may preclude wrongfulness is the so-called ‘state of necessity’.Footnote 16 It has been said that, ‘[w]hen a state invokes necessity, it claims that a situation is beyond the boundaries of the normal operation of law’.Footnote 17 The discussion in the following sections will demonstrate that this same concept of necessity exists in both IHL and IHRL.
Article 25 of the International Law Commission's (ILC) Draft Articles on State Responsibility confirms that necessity may be invoked as a circumstance precluding wrongfulness only in certain limited situations. First, necessity may not be invoked unless the act ‘is the only way for the State to safeguard an essential interest against a grave and imminent peril’ and ‘does not seriously impair an essential interest of the State or States towards which the obligation exists, or of the international community as a whole’.Footnote 18 Second, necessity may never be invoked to preclude wrongfulness if the international obligation in question excludes such reliance or the state has contributed to that situation of necessity.Footnote 19
Two features of necessity in general international law are particularly relevant to the discussion in this article. First, the commentary to Article 25 highlights an important limit on the extent to which necessity may be invoked: ‘the requirement of necessity is inherent in the plea: any conduct going beyond what is strictly necessary for the purpose will not be covered.’Footnote 20 As an important corollary of this, ‘[t]he defence will only persist as long as the situation of necessity itself persists’.Footnote 21 Whilst necessity is therefore invoked primarily as a permissive doctrine, it also has self-defined limits. As will be shown in the following sections, this feature of necessity is shared by its manifestations in IHL and IHRL, and it is particularly important to the proposals made in Section 5.
Second, the ICJ – after confirming that necessity is a circumstance precluding wrongfulness and the conditions for its invocation laid down in Article 25 of the ILC Articles reflect customary international lawFootnote 22 – made clear that ‘the State concerned is not the sole judge of whether those conditions have been met’.Footnote 23 This is consistent with the view that self-judging standards cannot be rules of international law but instead simply reflect a political principle.Footnote 24 This feature of necessity will again be drawn on in Section 5 as an aspect of the proposals made there for understanding the relationship between IHL and IHRL.
With this idea of necessity in general international law in mind, we can now turn to the form in which considerations of necessity manifest in IHL and IHRL.
3. Necessity in International Humanitarian Law
This section will demonstrate that necessity is relevant to IHL in two important respects: first, as the principle of military necessity, which is balanced against humanitarian considerations in each rule of IHL; and, second, as the basic raison d'être for the entire corpus of IHL. Whilst the first function of necessity has been relatively well explored in commentaries, the second function has received very little attention. This section will examine each in turn.
3.1 Military Necessity as a Balancing Principle in IHL
In the first sense, considerations of necessity manifest in IHL as the principle of military necessity. The Lieber Code contains the classic definition of this principle: ‘[m]ilitary necessity, as understood by modern civilized nations, consists in the necessity of those measures which are indispensable for securing the ends of the war, and which are lawful according to the modern law and usages of war.’Footnote 25 It is generally acknowledged that military necessity operates as a balance against humanitarian considerations and that this balance represents the overall framework of IHL.Footnote 26 This can be seen in one of the earliest documents codifying the laws and customs of war, the 1868 St Petersburg Declaration Renouncing the Use of Explosive Projectiles.Footnote 27 The Preamble to the Declaration states that it was its purpose to ‘[fix] the technical limits at which the necessities of war ought to yield to the requirements of humanity’. Military necessity is here established in opposition to considerations of humanity: whilst necessity denotes the freedom of parties to an armed conflict to do what is necessary to win the war, humanitarian considerations establish the limits of that freedom.
This balance between humanity and military necessity can also be seen in certain specific rules of IHL.Footnote 28 For example, Article 54(2) of the First Additional Protocol (AP I) prohibits attacks against objects indispensable for the survival of the civilian population.Footnote 29 AP I Article 54(5) then goes on to state:
In recognition of the vital requirements of any Party to the conflict in the defence of its national territory against invasion, derogation from the prohibitions contained in paragraph 2 may be made by a Party to the conflict within such territory under its own control where required by imperative military necessity.
‘Imperative military necessity’ may be invoked here as justification for derogating from the rule prohibiting attacks.Footnote 30 The role played by military necessity here mirrors that played by necessity as a circumstance precluding wrongfulness under the law of state responsibility – that is, as a justification for departing from the normally applicable rules.Footnote 31 Moreover, this balancing of considerations of military necessity with considerations of humanity is not limited to those rules that explicitly demonstrate these two opposing principles. Rather, it is commonly argued that ‘[e]very one of [IHL's] rules constitutes a dialectical compromise between these two opposing forces’.Footnote 32 Indeed, it is because military necessity has already been factored into each rule of IHL that one cannot plead necessity as a justification for transgressions of IHL.Footnote 33 The classic example where such a claim was made was the German military doctrine of Kriegsraison geht vor Kriegsmanier (necessity in war overrules the manner of warfare), which held that military necessity could justify divergence from the laws and customs of war.Footnote 34 This, however, was rejected in a number of the trials that followed the Second World War.Footnote 35 Thus, only where a rule of IHL explicitly provides for reliance on military necessity as a basis for derogating from the normally applicable standard can such arguments be invoked.Footnote 36
An important feature of military necessity must be mentioned at this stage. Whilst it has thus far been discussed primarily as a permissive principle, in tension with restrictive considerations of humanity, it is to be noted that in reality the relationship between the two is more nuanced. This is because military necessity, although often invoked as a justification for certain acts committed in armed conflict, is inherently self-limiting. In other words, one cannot invoke military necessity (for example, in the form in which it appears in AP I Article 54(5)) as justification for something that is not strictly necessary.Footnote 37 Indeed, certain commentators go further than this and argue that, more generally, ‘the principle of necessity operates as an additional level of restraint by prohibiting acts which are not otherwise illegal, as long as they are not necessary for the achievement of legitimate goals’.Footnote 38 Whether one follows this more restrictive notion of military necessity or not, the fact that the principle has a self-defined limit reflects a clear analogy with the discussion above of necessity under the secondary rules on state responsibility. There it was noted that, although necessity operates as a circumstance precluding wrongfulness and thus a permissive doctrine, it is also self-limiting.Footnote 39 The same is true of military necessity in IHL.Footnote 40 Indeed, when recognising the limiting aspect of military necessity, its relationship with humanitarian considerations no longer appears to be one of countervailing principles; rather, they operate as ‘two aspects of the same principle’, with the boundary of what is militarily necessary defining the point at which humanity becomes the decisive consideration.Footnote 41
3.2 Necessity as a Constitutive Principle in IHL
There is, however, a second, more fundamental way in which necessity may be seen to operate in IHL, and it is from this that its other manifestations discussed above arguably flow. This is its constitutive role in IHL. In other words, it is the underlying state of necessity (which exists by virtue of an international or non-international armed conflict) that is the raison d'être of IHL; it is that state of necessity which explains the non-adherence to many of the normal peacetime rules of law (such as the ordinary domestic law and IHRL with regard to a state's internal actions, and normal interstate relations with regard to a state's external actions). Without this underlying state of necessity, there would be no need for a separate body of law to govern the particular situation. Furthermore, because of this constitutive function of necessity in IHL, we also see it manifesting in the manner discussed above, through the principle of military necessity inherent in each rule of IHL.
It was explained that the first function of necessity in IHL (as a principle in balance with humanitarian considerations) operates in a similar way to that of necessity as a circumstance precluding wrongfulness under the law of state responsibility.Footnote 42 However, it is the relationship of this second, constitutive function of necessity in IHL to the so-called state of necessity in general international law that is particularly interesting. According to this constitutive function, IHL is a legal regime designed specifically to address a particular state of necessity (armed conflict) and it elaborates the minimum rules applicable in such situations. This has been recognised in several cases and commentaries. In the Krupp case before the US Military Tribunal at Nuremberg, for example, the tribunal rejected the doctrine of Kriegsraison, discussed above,Footnote 43 on the basis that it is the very state of necessity being invoked by that doctrine that forms the rationale for the existence of IHL as a body of rules.Footnote 44 More recently, during the drafting of what became Article 25 of the ILC Articles, the ILC – in the section of its Eighth Report discussing necessity in general international law – made clear that the object and purpose of IHL is to elaborate a set of rules that are to apply in a state of necessity:Footnote 45
Military necessity appears in the first place as the underlying criterion for the whole series of substantive rules of the law of war and neutrality, namely, those rules which, by derogation from the principles of the law of peace, confer on a belligerent State the legal faculty of resorting, against the enemy and against neutral States (and against their nationals), to actions which meet the needs of the conduct of hostilities … this ‘necessity of war’ … is the basis of the rule [of IHL] and its applicability …
The principle underpinning the general international law doctrine of necessity thus justifies the entire regime of IHL. As was noted above, regarding necessity in general international law, ‘[w]hen a state invokes necessity, it claims that a situation is beyond the boundaries of the normal operation of law’.Footnote 46 This lies at the heart of IHL as a legal regime: the ordinary rules of peacetime are considered to be inappropriate for safeguarding the essential interests of states during situations of armed conflict.
Very little attention has been given to the constitutive function of necessity in IHL. However, it is submitted that appreciating this second function of necessity is essential for understanding the presumptions that underlie that body of law and inform its rules. Let us take an example to illustrate this. It is well established that members of armed forces party to an international armed conflict are entitled to combatant status.Footnote 47 This entitlement has a number of important consequences. On the one hand, where a combatant is captured by enemy armed forces, he or she becomes a prisoner of war, subject to the robust system of protection established by the Third Geneva Convention (GC III),Footnote 48 and may not be prosecuted for their ‘ordinary’ acts of war.Footnote 49 On the other hand, such persons may be targeted solely on the basis of their status (‘status-based targeting’) for as long as hostilities continue,Footnote 50 and they may automatically be interned for the duration of hostilities (‘status-based internment’).Footnote 51 Consequently, their status alone is sufficient to render combatants targetable and detainable, with no requirement that the enemy armed forces determine the individual threat posed.Footnote 52 This is in contrast to civilians, for whom a ‘conduct-based’ approach to targeting and internment is taken. Under this model, individual civilians may be targeted only where, and for as long as, they directly participate in hostilities,Footnote 53 and they may be interned only if they pose such a threat to the security of the state as to necessitate internment.Footnote 54 Appreciating that the rationale of IHL lies in its attempt to elaborate a set of rules applicable in an underlying state of necessity, to which many of the normal peacetime rules are considered inappropriate, helps with understanding the status-based approach to combatant targeting and internment. This is because, once that underlying state of necessity (the armed conflict) exists, IHL prescribes a set of rules which it presumes to be necessary for as long as the armed conflict persists. Thus, the status of combatant creates a presumption that those persons holding that status ipso facto constitute a threat to the security of the enemy armed forces by virtue of their potential participation in hostilities. That threat is then presumed to necessitate the targeting or interning of such persons for as long as the underlying state of necessity continues; no review of the actual necessity of interning or targeting in the specific circumstances is thought to be needed given the continuation of the underlying state of necessity.Footnote 55
Recognising this constitutive role of necessity in IHL therefore helps to explain the presumptions that inform many of its rules. As will be demonstrated in the following section, it is with regard to these presumptions that IHL differs most from IHRL. It is a fundamental argument of this article that this constitutive function of necessity in IHL should be borne in mind in interpreting and applying the law and, in particular, in trying to rationalise its relationship with IHRL; we will return to this point in Section 5.
4. Necessity in International Human Rights Law
Having considered the role of necessity in IHL, this section will now consider its role in IHRL. As noted above, commentators have emphasised the principle of humanity as the ‘common denominator’ of IHL and IHRL.Footnote 56 However, rarely is necessity explored as a principle common to both of these bodies of law.Footnote 57 Indeed, the presence of considerations of military necessity in IHL has been invoked as a basis for differentiating it from IHRL.Footnote 58 It is true that military necessity plays no role in IHRL. As was explained in the previous section, it is the underlying state of necessity which forms the raison d'être of IHL, and it is from that underlying situation that the notion of military necessity is derived, which accounts for many of the more permissive rules, such as the right to target enemy combatants.Footnote 59 Unlike IHL, however, IHRL does not begin from an underlying state of necessity, but rather it sets standards that are to govern ‘everyday’ relations between states and individuals.Footnote 60 Its applicability is thus not limited to a particular situation, but instead extends to all situations.
However, whilst military necessity as such is not a consideration in IHRL, it is not the case that necessity plays no role. In particular, necessity lies at the heart of the limitation and derogation clauses found in the major human rights treaties.Footnote 61 As with necessity in general international law,Footnote 62 the purpose of these limitation and derogation clauses is to enable the law to become sensitive to the particular context: a state is therefore excused from failing to honour its obligations where the extraordinary circumstances render it necessary to depart from the ordinarily applicable rules.Footnote 63 Considerations of necessity therefore inform IHRL as well as IHL. Indeed, this transcendence of necessity throughout different areas of international law may be seen as an inevitable consequence of the fact that, as parts of the international legal order, IHL and IHRL are limited by the positivist, consent-based notion of international legal obligation: states are thus eager to ensure that their scope of lawful action is not constrained to the point of becoming insensitive to circumstance.Footnote 64
It is not necessary to discuss in full the various limitation and derogation clauses in IHRL. Instead, the focus here will be on derogation clauses, as most illustrative of the role of necessity, and those conditions limiting the right to derogate that are of relevance to the arguments in this article. A typical derogation clause can be found in Article 4(1) of the International Covenant on Civil and Political Rights (ICCPR):
In time of public emergency which threatens the life of the nation and the existence of which is officially proclaimed, the States Parties to the present Covenant may take measures derogating from their obligations under the present Covenant to the extent strictly required by the exigencies of the situation, provided that such measures are not inconsistent with their other obligations under international law and do not involve discrimination solely on the ground of race, colour, sex, language, religion or social origin.
Article 4(2) ICCPR then goes on to list certain rights, such as the prohibition against torture, as non-derogable, even in times of public emergency.Footnote 65 Commentators have recognised that necessity lies at the heart of these provisions.Footnote 66 Indeed, Roberto Ago has commented on the provenance of the limitation and derogation clauses in human rights treaties in the general international law doctrine of necessity.Footnote 67 This has important implications for the ability of a state to rely on necessity as a circumstance precluding wrongfulness at the secondary level where the primary rule is one of IHRL. Thus, as was shown above, the fact that considerations of necessity have been incorporated into the primary rules of IHL excludes reliance on necessity at the secondary level as a circumstance precluding wrongfulness.Footnote 68 The same appears to be true with regard to human rights treaties, and it has been argued that the inclusion of considerations of necessity in the primary rules (through limitation and derogation clauses) precludes reliance on necessity at the secondary level.Footnote 69 Thus, just as IHL elaborates the legal rules applicable in a specific state of necessity, so IHRL elaborates the conditions under which the normally applicable rules may be derogated from on the basis of necessity, and this incorporation of necessity excludes reliance on such a claim under the law of state responsibility.Footnote 70
Necessity therefore plays a prominent role in both IHL and IHRL. However, this is not to suggest that its role is identical in each. Rather, the degree of similarity depends on the particular function of necessity in IHL that one is considering. Thus, it was explained in the previous section that necessity operates in two ways in IHL: first, as a balancing principle against considerations of humanity, illustrated in part by express references to military necessity as justification for derogating from the normally applicable rules; second, as a constitutive principle, providing the rationale for the very existence of IHL. In the first sense, to the extent that necessity is explicitly incorporated into the rule as a basis for derogating from the normal standards, it operates in much the same way as it does in the derogation provisions in human rights treaties.Footnote 71 However, these similarities end when one considers the second function of necessity in IHL (its constitutive role) and the presumptions that flow from this. First, necessity operates here in a very different manner from that in IHRL as, rather than acting as an exception to the general rules laid down by the relevant treaty, it forms the raison d'être of the entire body of rules. Second, as was explained above, it is on this constitutive function that many of the presumptions inherent in IHL are justified. In particular, it was argued that the status-based targeting and internment regimes applicable to combatants in international armed conflicts are considered appropriate given the underlying state of necessity, which leads to a blanket presumption that combatants constitute a security threat necessitating lethal force or internment for the duration of hostilities.Footnote 72 This is in stark contrast to derogation under IHRL, where no such blanket presumption of necessity can be made. Instead, derogation is permitted only ‘to the extent strictly required by the exigencies of the situation’.Footnote 73 This requires that both the general derogation and each measure adopted pursuant thereto are not only necessary to respond to the threat but also proportionate to that end – that is, the least rights-restrictive approach.Footnote 74 The kinds of status-based determination made under IHL with regard to the necessity of targeting and interning combatants are, consequently, impermissible under IHRL. Recognising this constitutive function of necessity in IHL, and the presumptions that flow therefrom, thus helps to explain some of the most fundamental differences between IHL and IHRL.
5. Necessity and the Relationship Between IHL and IHRL
The previous sections have demonstrated that necessity operates in both IHL and IHRL. It was shown how certain fundamental differences between these two bodies of law can be explained by the differing roles played by necessity in each. This section will now offer some tentative proposals for how that analysis might help in establishing a principled approach to the interaction between a conduct of hostilities and a law enforcement framework in regulating complex conflict situations. By ‘complex conflict situations’ is meant primarily non-international armed conflicts and military occupations to which both IHL and IHRL are applicable;Footnote 75 it is in such situations that determining the relationship between IHL and IHRL becomes particularly important.Footnote 76 Non-international armed conflicts and military occupations often involve highly asymmetric relationships, whether between a state and a civilian population or a state and non-state armed groups.Footnote 77 One consequence of this is that both ‘conflict’ and ‘peacetime’ situations can arise side by side, raising questions about how one should move between a ‘conduct of hostilities’ framework and a ‘law enforcement’ framework in regulating such situations.Footnote 78 However, it must be noted that situations can also arise in other international armed conflicts, which might more appropriately be regulated as law enforcement operations. Where this is the case, the arguments made in this section would also apply there. However, the focus will be on non-international armed conflicts and military occupations as most clearly reflecting the tension between a conduct of hostilities and law enforcement approach to regulation. It is also important to emphasise at the outset that this section seeks to make proposals regarding how the law might develop; it is therefore concerned not with the lex lata but rather with the lex ferenda.
Essentially, it is proposed here that the raison d'être of IHL be reclaimed by taking greater account of the constitutive function of necessity, whilst divorcing this from the various presumptions that are currently thought to flow from it. It is argued that IHL must be reframed as a set of rules designed to deal with a state of necessity. By feeding this notion of necessity back into IHL as a whole, we can then use it to influence how we think of its application in specific situations and its interaction with IHRL. This approach is developed in the first subsection below. The two subsections that follow then demonstrate how the proposal made will operate in practice, first, by exploring its implications for the recent doctrinal debate regarding the so-called ‘duty to capture’ in IHL and, second, by considering its impact on the interaction between the IHL and IHRL rules on detention.
5.1 Implications for the Relationship between IHL and IHRL
The approach proposed here is that the necessity-based analysis adopted in the preceding sections be applied to help to rationalise the relationship between a conduct of hostilities (IHL) approach and a law enforcement (IHRL) approach in complex conflict situations. In particular, it is submitted that the constitutive function of necessity in IHL should be emphasised and that certain features of necessity in both general international law and in IHRL should be drawn on in determining the applicability of IHL and its interaction with IHRL. Thus, as was discussed in Section 3, IHL is a legal regime developed to elaborate a set of rules to apply in a state of necessity – that is, a situation where it is necessary to depart from the normal peacetime rules in order to safeguard an ‘essential interest’ (which, in the case of an armed conflict, could include achieving a legitimate military purpose).Footnote 79 A clear starting point for addressing the interaction between IHL and IHRL in a particular situation is then established: the normal peacetime regime provided by domestic law and IHRL constitutes the default legal framework. Any operations, whether they involve use of force or detention, for example, would be law enforcement operations that would have to meet the standards of IHRL. Where it becomes necessary to depart from these normal peacetime rules in order to safeguard an essential interest (that is, to achieve a legitimate military goal), then the (more permissive) rules of IHL become the relevant standards. In non-international armed conflicts, where there is a dearth of applicable treaty rules of IHL, the protective rules applicable in international armed conflicts should be applied by analogy, alongside applicable customary rules.Footnote 80
This does not, however, mean that IHRL is no longer relevant once a determination has been made that it is necessary to revert to an IHL framework. Instead, the approach adopted above does not require ‘choosing’ between either IHL or IHRL; rather, IHL, when it applies, would operate ‘through’ IHRL, which would continue to apply. Thus, when it is considered necessary to revert to an IHL model, where possible the default IHRL rules should be interpreted so as to accommodate IHL. This was, for example, the approach adopted by the ICJ in its Nuclear Weapons advisory opinion, in which it held that the arbitrary deprivation of life prohibition in IHRL could be interpreted according to the rules of IHL on the conduct of hostilities, given the context (that is, armed conflict) in which the right was being interpreted.Footnote 81 In such a case, IHRL would continue to apply but would be interpreted according to IHL. Where such an interpretive resolution is not possible, however, then we can rely on necessity in the form of derogation clauses in applicable human rights treaties in order to widen the scope of permissible state action and create the necessary space for IHL. Importantly, as stated above, when a state derogates from its obligations under a human rights treaty, that does not leave the actions of that state unregulated; derogation and the specific measures adopted pursuant thereto must be shown to be ‘strictly required [and no more than is strictly required] by the exigencies of the situation’.Footnote 82 Moreover, the derogating state remains subject to the careful scrutiny of the relevant enforcement body (such as the European Court of Human Rights (ECtHR) for states party to the European Convention on Human Rights (ECHR).Footnote 83
Emphasising the constitutive function of necessity in IHL can therefore help to rationalise the relationship between IHL and IHRL in particular situations. It also allows us to draw on features of necessity in general international law and IHRL in order to clarify when the default legal regime (IHRL) should give way to the exception (IHL). In particular, three aspects of necessity in general international law and in IHRL may help to guide us here. First, and most fundamentally, the necessity of reverting to a conduct of hostilities (IHL) model is not to be a blanket determination that is presumed once an armed conflict exists, as is currently the case,Footnote 84 but instead should be determined in the prevailing circumstances. Moreover, the determination should concern the necessity of reverting not to IHL as a legal regime but rather to the specific norm of IHL in the circumstances. For example, whilst it may be considered necessary to apply the internment regime found in the Fourth Geneva Convention to civilians,Footnote 85 it may not be necessary to use the status-based targeting powers granted by IHL.Footnote 86 This was shown to be the approach taken with regard to necessity in both general international lawFootnote 87 and in IHRL.Footnote 88 The determination that it is necessary to revert to an IHL framework in a particular situation could be made at commander level in order to ensure that the system is workable.Footnote 89
Second, reliance on IHL as the governing framework in a particular situation should persist only for as long as it remains necessary for the military objective and is proportionate to that end. This is consistent with the approach taken to the invocation of necessity in general international law,Footnote 90 as well as the right to derogate under the human rights treaties, both of which are premised on the temporary and exceptional nature of the claim.Footnote 91
Third, as with the invocation of necessity under the law of state responsibility, the question of when it is necessary to revert to an IHL paradigm must not be considered self-judging but rather would be an objective standard, susceptible to judicial review.Footnote 92 That said, in order to ensure that the approach is workable, a useful tool that might be borrowed from the system of derogation under the ECHR is the notion of a state's ‘margin of appreciation’, whereby deference is given to the derogating state ‘to determine whether [the life of the nation] is threatened by a “public emergency” and, if so, how far it is necessary to go in attempting to overcome the emergency’.Footnote 93 The European Court of Human Rights has confirmed that, notwithstanding such a margin of appreciation, the authority to derogate in a specific case remains an objective test subject to judicial review.Footnote 94 This margin of appreciation could similarly be applied where there is ex post facto judicial review of the determination that it is necessary to revert to an IHL norm in a specific situation.
It is submitted that the approach advocated here has a number of advantages over other proposals. Cordula Droege, for example, has argued:Footnote 95
To apply human rights law is … only realistic if it is feasible to use the means of law enforcement, thus only in operations conducted by security forces (whether military or police) with some effective control over the situation. In those cases, human rights law constitutes the lex specialis. In combat situations, on the other hand, humanitarian law constitutes the lex specialis.
Droege elaborates this notion of ‘effective control’ by reference to certain criteria, such as geographical proximity with a ‘conflict zone’, degree of armed resistance, duration of combat operations and types of weapon used.Footnote 96 Droege's thesis, like the one proposed in this article, recognises that IHL should not necessarily be considered the lex specialis purely on the basis of a situation being labelled an armed conflict. However, the approach adopted in this article differs in a number of important respects. Most fundamentally, because the current thesis emphasises the constitutive function of necessity in IHL, its starting point is very different from Droege's, who suggests that applying human rights law is feasible only where the state exercises ‘effective control’. To the contrary, the argument made in this article is that the default legal regime is always the ‘ordinary’ peacetime rules (that is, IHRL and the law enforcement model); IHL is the extraordinary ‘state of necessity’ model. The question, therefore, is not whether it is feasible to honour the IHRL standards, but rather whether it is actually necessary for the accomplishment of a legitimate military objective to depart from those standards. This is an important distinction, for the burden of proof under the proposal made here rests with the party wishing to invoke the more permissive standards under IHL.
Other commentators, too, have suggested ways of reconciling IHL and IHRL in complex conflict situations. David Kretzmer and Charles Garraway, for example, suggest relying on the applicability conditions of the Second Additional Protocol (AP II)Footnote 97 as governing the point of transition from a human rights to an IHL model for the regulation of non-international armed conflicts, with a view to limiting the permissive rules of IHL only to the most serious situations.Footnote 98 However, it is submitted that such approaches would still place too much reliance on the legal categorisation of a situation, whereas the thesis adopted here would provide greater flexibility in allowing the applicable rules to become sensitive to the circumstances. In addition, the argument made in this article would also consider the necessity of reverting to individual rules of IHL, rather than the apparent necessity of reverting to IHL as a legal regime. Finally, it also allows for the co-application of these two bodies of law, rather than a binary, either/or approach. It is argued that the proposals made in this article are more sympathetic to IHL's object and purpose, as they are premised on the notion that the specific rules of IHL were developed to regulate an extraordinary situation and should therefore only be invoked in cases of genuine necessity.
By reframing IHL in terms of necessity, a principled approach to the interaction between a conduct of hostilities and a law enforcement framework for regulating certain situations can, therefore, be developed. A few caveats should be noted at this stage. First, the focus of this article is on situations where IHL and IHRL clash. It is not concerned with those issues that are regulated only by one set of rules or those to which both IHL and IHRL apply but where the two point in the same direction; in such cases, there is no need to consider the interaction between IHL and IHRL.Footnote 99 Second, the proposals made in this section are limited to situations to which both IHL and IHRL currently apply, that is the arguments made cannot be invoked to justify relying on IHL outside armed conflict. Finally, as this article is concerned with the relationship between obligations under IHL and IHRL, its focus is on the state that is party to a particular armed conflict and not on non-state groups that may be parties, for the latter are not generally bound by IHRL.Footnote 100
The following two subsections will now demonstrate, with reference to two examples, how the proposals made in this section would operate in practice.
5.2 Example I: The ‘Capture or Kill’ Debate
The approach advocated in the previous section would have important implications for recent debates regarding the alleged duty to capture instead of killing those who are otherwise lawful targets under IHL.Footnote 101 A recent contribution to this debate was made by the International Committee of the Red Cross (ICRC) in its Interpretive Guidance on Direct Participation in Hostilities, which included the following in its Section IX: ‘the kind and degree of force which is permissible against persons not entitled to protection against direct attack must not exceed what is actually necessary to accomplish a legitimate military purpose in the prevailing circumstances.’Footnote 102 The ICRC implied in its Interpretive Guidance that such determinations of necessity should be made at the commander level.Footnote 103 The ICRC justified its conclusion here on the basis of the inherently limiting nature of the principles of military necessity and humanity, ‘which underlie and inform the entire normative framework of IHL’:Footnote 104
In conjunction, the principles of military necessity and of humanity reduce the sum total of permissible military action from that which IHL does not expressly prohibit to that which is actually necessary for the accomplishment of a legitimate military purpose in the prevailing circumstances.
This quickly became the most controversial aspect of the ICRC's Interpretive Guidance.Footnote 105 It has been heavily criticised by a number of scholars for its alleged misrepresentation of the current lex lata.Footnote 106 It is argued that it imposes an additional requirement on states, wholly unknown to IHL, and that the necessity of a state's actions during armed conflict has already been factored into the specific rules. As Michael Schmitt argues, ‘military necessity infuses IHL; it is not a prohibition which applies over and above the extant rules’.Footnote 107 In other words, so the argument goes, states have already decided that it is necessary and proportionate to target combatants on the basis of their status alone.Footnote 108
It is not the purpose of this section to examine whether Section IX accurately reflects the current state of IHL.Footnote 109 Rather, it is concerned with the impact that the proposals made in the preceding section regarding the interaction between IHL and IHRL might have on this debate. Thus, if IHL is reframed in such a way as to emphasise the second, constitutive function of necessity, the ICRC's approach would no longer seem so antithetical to that body of law. Indeed, the quote above from the ICRC's Interpretive Guidance reflects the fact that the ICRC relied on the first conception of necessity noted above (that is, as a general principle which, balanced against humanity, informs every rule) to justify its recommendation.Footnote 110 However, since one can point to necessity having already been taken into account in the specific rules of IHL, it makes assertions that it also sits above those rules as an additional constraint much harder to support.Footnote 111 The difficulty for the ICRC was that it was applying an IHL paradigm whilst suggesting limits on that paradigm that many reject. However, the same result could be achieved by adopting the approach suggested in the previous section and relying on the constitutive function of necessity in IHL. As advocated in that section, IHL should be emphasised as a body of rules developed to regulate a state of necessity. As such, the ordinary, peacetime rules of domestic law and IHRL should constitute the default legal regime, with the more permissive rules of IHL applying alongside these only where this is necessary for the accomplishment of a legitimate military objective. The consequence would be that the approach advocated in Section IX of the ICRC's Interpretive Guidance would be followed by virtue of the fact that IHRL would constitute the default applicable regime, which permits lethal force only where no less rights-restrictive means are available to protect against serious violence.Footnote 112 Under this model, the approach in Section IX would be honoured. Moreover, in order then to revert to the more permissive IHL rules (such as those permitting the targeting of combatants, civilians directly participating in hostilities, or members of armed groups performing a continuous combat function), it would have to be shown that it was actually necessary, and no more than was necessary, in the prevailing circumstances; this test would not be met where a less draconian means (for example, capture and detention) could be employed to achieve the desired military objective, such as removing the individual from the battlefield. The mere fact that a person is a combatant or a civilian directly participating in hostilities would, therefore, no longer be considered sufficient justification to use lethal force.
In reverting to the IHL model, as stated in the previous section, IHRL does not cease to apply. Rather, the applicable human rights obligations of the state should be interpreted in accordance with IHL where this is possible, as suggested by the ICJ in the Nuclear Weapons opinion with regard to the arbitrary deprivation of life prohibition in the ICCPR. Where such consistent interpretation is not possible, however, the state should derogate. This would be required, for example, for those states party to the ECHR, Article 2(2) of which – rather than laying down a general prohibition of arbitrary deprivation of life, which could be interpreted in accordance with IHL – sets out an exhaustive list of permissible grounds for deprivation of life, none of which can be considered compatible with IHL's permitted use of targeting for the sole purpose of removing an individual from the battlefield.Footnote 113 Indeed, Article 15(2) ECHR specifically permits derogation from Article 2(2) ‘in respect of deaths resulting from lawful acts of war’, calling for a renvoi to IHL. As noted, when a state derogates under a human rights treaty, its actions are not then unregulated, but rather continue to be restricted by the requirements of necessity and proportionality which apply to the actions of the state pursuant to derogation.
The approach advocated in the previous section would therefore have the same effect as Section IX of the ICRC's Interpretive Guidance, without having to argue that military necessity currently operates as both a balancing principle in each rule of IHL and as an additional limiting principle that sits over and above every rule. Rather, by emphasising the constitutive function of necessity in IHL and thus its underlying object and purpose, the same result of restricting the more permissive rules of IHL to those situations where it is truly necessary can be achieved. Indeed, recent practice of the Colombian government in its non-international armed conflict adopts an approach similar to that advocated here. Thus, its 2009 Manuel de Derecho Operacional (Manual of Law Governing Operations) distinguishes between operations during military hostilities (governed by so-called ‘red card rules’) and operations to maintain security (governed by ‘blue card rules’).Footnote 114 The former are modelled primarily on the rules regulating the use of force under IHL applicable in international armed conflicts (thus, force can be used whenever the target constitutes a military objective), with the human rights-inspired exception that ‘[i]f circumstances permit, demobilization and capture are favoured over deaths in combat’.Footnote 115 Blue card operations, on the other hand, are treated entirely as law enforcement operations, governed solely by rules modelled on the IHRL standards governing the use of force (thus, force must be a last resort to be used to counter a threat in a proportionate manner).Footnote 116 Which of the two sets of rules applies to a given operation is determined by an advisory board (comprising the heads of the police, armed forces and intelligence agencies), which meets to determine which rules are applicable to a conflict with a particular group.Footnote 117 This approach mirrors that advocated in the present article and would allow the legal framework to remain sensitive to the prevailing circumstances.Footnote 118 Whether such an approach is adopted in other cases will depend on a number of factors, not least of all the political will of the states involved.
5.3 Example II: Detention
The way in which the thesis proposed in this article would operate in practice can also usefully be demonstrated with reference to the regulation of preventive, security detention or ‘internment’. IHL applicable in international armed conflicts permits states to intern both combatants for the duration of hostilities, on the basis of their status alone, and civilians only if and for as long as they pose a security threat necessitating internment.Footnote 119 Under these rules, prisoners of war (POWs) are not entitled to any form of review regarding the necessity of their internment,Footnote 120 whilst civilians are assured a very minimal form of non-judicial initial and periodic review.Footnote 121 In the situations with which we are dealing here (that is, belligerent occupation and non-international armed conflicts) this area of IHL is unsatisfactory. Regarding occupied territory, these rules fail adequately to reflect the range of situations that may exist. Thus, as noted, it is in such circumstances that ‘everyday’ situations, which are more appropriately addressed through a purely law enforcement paradigm, arise alongside hostilities. Whilst preventive detention may at times be necessary in the prevailing circumstances, automatic internment of POWs for the duration of hostilities, or indefinite internment without judicial review of civilians considered to be a security threat, may not actually be necessary at all (or most) times during the occupation. Rather, it might instead be reasonable to continue to ensure access to habeas corpus in accordance with the approach taken in IHRL regarding review of detention.Footnote 122 Furthermore, with regard to non-international armed conflicts, IHL lays down no rules regulating internment, thus leaving the law in a particularly unclear state.Footnote 123 This has resulted in considerable deficiencies in the detention regimes adopted by states that are party to non-international armed conflicts.Footnote 124
As with the use of lethal force, discussed above, the necessity-based analysis developed in this article could help to establish a principled basis for the interaction between the IHL and IHRL rules in this area. Thus, in emphasising the rationale of IHL as a set of rules designed to regulate a state of necessity (the exception), we can once again establish IHRL as setting the default standards. These rules require, inter alia, that any deprivation of liberty (regardless of the individual's status under IHL) is based on grounds established in law, is non-arbitrary in the sense of being just, predictable and reasonable, and is subject to judicial review.Footnote 125 Only where it becomes actually necessary in the prevailing circumstances for the accomplishment of a legitimate military objective (such as to remove a person from the battlefield) can a state revert to one of the IHL internment regimes. In occupied territory, this would involve applying the Third Geneva Convention (GC III) and/or Article 78 of the Fourth Geneva Convention (GC IV) directly. In non-international armed conflicts, however, as noted above, no equivalent internment regime exists under IHL. In such situations, states have commonly developed such a regime by drawing by analogy from Article 78 GC IV.Footnote 126 Certain commentators have endorsed this model as providing an appropriate balance between the state's security needs and the individual's fundamental rights.Footnote 127 Given the conceptual and evidential uncertainty regarding the notion of membership of non-state armed groups,Footnote 128 it is submitted that the status-based internment model in GC III would not be appropriate for non-international armed conflicts.
Where it is considered necessary to revert to the IHL model, this should again be done through IHRL. Thus, in a manner similar to the ICJ's approach to interpreting the right to life in situations of armed conflict, the general standard prohibiting the arbitrary deprivation of liberty in most human rights treaties can be interpreted according to the IHL internment regime, such that internment of POWs in occupied territory in accordance with GC III would not be considered arbitrary, for example. However, for states party to the ECHR, internment in itself would not be lawful, for Article 5(1) sets out an exhaustive list of permissible grounds for detention, which does not include preventive detention for reasons of security; in such cases, derogation from Article 5(1) would be necessary.Footnote 129 Indeed, the fact that derogation under the human rights treaties can be used to accommodate certain detention practices that are typical during armed conflict was recently acknowledged by the European Court of Human Rights.Footnote 130 In addition, derogation may also be necessary for other aspects of the IHL internment regimes. Most importantly, the absence of any review of POW internment and the use of non-judicial processes of review for civilian internment would be incompatible with the requirement under IHRL that all persons deprived of their liberty be ensured the right to habeas corpus.Footnote 131 In these cases, derogation would again appear to be necessary. However, it is often said that the right to habeas corpus is non-derogable.Footnote 132 Whilst this right should never be eliminated, it may be that derogation could serve to loosen the requirements of this rule, allowing for the review procedures provided for by IHL.Footnote 133 Indeed, this has been accepted by the European Court of Human Rights.Footnote 134
Once again, therefore, we are relying on the manifestations of necessity in IHL (in its constitutive form) and in IHRL (in the form of derogation) to help rationalise the relationship between these two bodies of rules with regard to detention. In so doing, we can again draw on several of the parameters of necessity in IHRL and general international law that were discussed above. First, the necessity of reverting to an IHL model of internment, such as that in GC III, is no longer to be a blanket determination (as is currently the case, for example, regarding the necessity of POW internment), but rather one to be made in the prevailing circumstances. The mere existence of a factual situation qualifying as either a situation of occupation or a non-international armed conflict is therefore not to be considered sufficient to justify recourse to one of the IHL internment regimes; rather, the actual necessity of so doing in a specific case must be shown to exist. As part of this, it may be that it is considered necessary to employ preventive, security detention, as provided for by IHL, but not necessary to exploit the limited review procedures, leaving intact full habeas corpus review under IHRL. Second, reverting to an IHL model of internment must be a temporary and exceptional measure. As such, if individuals are interned according to an IHL model, they should be brought under a human rights model as soon as possible, for example, by being given access to a court to challenge the legality of their detention. This might be the case where individuals are initially detained in the course of hostilities, during which it may not be possible to ensure their access to habeas corpus, but after which that access should be renewed. Finally, the necessity of reverting to an IHL model of internment is not to be considered self-judging, but rather must be considered subject to objective review. Here, for example, the review body under Article 78 GC IV can play an important role in keeping a check on the necessity of invoking these provisions.
As this article has sought to demonstrate throughout, the approach advocated here has the key advantage that it is sympathetic to the raison d'être of IHL, recognising that that body of rules is designed to apply only in the most extraordinary of circumstances. It is here that this approach has the major advantage over other proposals made in this area. For example, it has often been said that, where the GC III and GC IV internment regimes apply, they should be considered lex specialis over other applicable rules of IHRL.Footnote 135 Moreover, given the absence of any rules regulating the grounds and procedures for internment in non-international armed conflict, commentators have favoured applying Article 78 GC IV by analogy as the lex specialis in such situations.Footnote 136 By relying on the raison d'être of IHL as the exception and taking as our starting point IHRL as the default, this approach provides a more nuanced account of the relationship between these two bodies of rules in a manner that allows them to become sensitive to the circumstances. Complex conflict situations, as noted, will often comprise a spectrum of situations, ranging from relative peace to hostilities. The IHL internment regimes should be applied only where the circumstances render it absolutely necessary to do so. In contrast to other proposals, the approach advocated here encourages such necessity to be judged in the prevailing circumstances, as opposed to making blanket determinations based solely on having met the threshold of an armed conflict.
Finally, as was the case in the previous section, there is practice supporting this approach to the regulation of detention. Thus, in its 2002 Report on Terrorism and Human Rights, the Inter-American Commission on Human Rights, in considering the rules applicable to detention, noted its view of the lex specialis nature of IHL in international armed conflicts.Footnote 137 It then went on to note an important caveat, however, stating that in ‘circumstances in which the continued existence of active hostilities becomes uncertain, or where a belligerent occupation continues over a prolonged period of time’, the relevant rules of IHL ‘may prove inadequate to properly safeguard the minimum human rights standards of detainees’.Footnote 138 In such situations, the Commission stated that the ‘supervisory mechanisms as well as judicial guarantees’ under IHRL and domestic law, such as habeas corpus and amparo, ‘may necessarily supersede international humanitarian law where this is necessary to safeguard the fundamental rights of those detainees’.Footnote 139 Once again, this approach differs from that proposed in this article insofar as its starting point is the lex specialis nature of IHL by virtue of the armed conflict. The approach taken in this article is rather the full application of IHRL as the default legal position, and it is submitted that this is more in keeping with IHL's object and purpose. However, importantly, the Commission recognises that, in certain situations, IHL may cease to be the most appropriate legal regime. This desire to move beyond the traditional assumption that a situation of armed conflict necessarily renders it appropriate to revert to IHL is essential to this article's central thesis that the constitutive function of necessity in IHL should be reclaimed.
6. A Caveat?
Before concluding, one potential caveat must be considered at this point. The previous section proposed drawing on necessity as developed in the law of state responsibility to help to interpret and apply IHL. However, one must bear in mind the differences between necessity as a principle in general international law and necessity as an element of IHL (and IHRL). Most importantly, as a principle in general international law, necessity operates as part of the secondary rules on state responsibility, whereas in IHL and IHRL it forms part of the primary rules.Footnote 140 As such, necessity in IHL and IHRL is relevant to the determination of the international obligations of states, whereas necessity in general international law operates at the secondary level, affecting when a state is responsible for a breach of those obligations.Footnote 141 This distinction between necessity in the primary and secondary rules has, in other areas, been invoked as a basis for arguing against the conflation of the two. For example, certain investment tribunals have held that, where exceptions on the basis of necessity have been intentionally incorporated into provisions of bilateral investment treaties, it is not appropriate to interpret these provisions according to the (more restrictive) doctrine of necessity in the secondary rules on state responsibility; it is argued that the two must be kept entirely separate.Footnote 142
Whilst it may well be valid for international tribunals to maintain the separation between the primary and secondary rules,Footnote 143 the proposals made in the previous section of this article avoid this trap by virtue of the fact that they are suggestions for how the law might develop in this area, rather than claims as to the current state of the law. Thus, there is no suggestion that the conditions applicable to necessity in general international law currently apply to restrict the application of IHL. Instead, it is argued de lege ferenda that drawing on necessity in the secondary rules to help to interpret the primary rules provides a useful means by which to reconcile the conduct of hostilities and law enforcement models in conflict situations. Moreover, it is consistent with the object and purpose of IHL, given that it is a body of law developed specifically to elaborate a set of rules that are applicable in a state of necessity.Footnote 144 Indeed, as noted above, this unique nature of IHL has been recognised and has been invoked as a basis for precluding recourse to the defence of necessity in the secondary rules on state responsibility.Footnote 145
7. Concluding Remarks
This article has explored the relationship between IHL and IHRL at the level of principle. It was noted at the outset that, whilst commentators often highlight the principle of humanity as being common to both IHL and IHRL, few attempts have been made to compare how considerations of necessity influence these areas of law. This article has sought to address this gap in the literature. In so doing, it has been shown that necessity plays a prominent role in both IHL and IHRL. The degree of convergence between the functions of necessity in each area, however, varies, depending in particular on which of the two notions of necessity in IHL is being considered. On the one hand, it was shown that military necessity operates as a balancing principle in IHL, in opposition to humanitarian considerations. In addition to implicitly informing every rule of IHL, this balance between humanity and necessity is made explicit in certain areas, where considerations of necessity operate as a basis for derogating from the normally applicable standards. In this sense, necessity operates in IHL in much the same way as it does in IHRL and in general international law. On the other hand, necessity was also shown to operate in a more basic, constitutive manner in IHL, justifying the entire body of rules. It was demonstrated that it is on that basic constitutive role of necessity that certain presumptions that permeate IHL are justified, such as those permitting status-based targeting and internment. It is with regard to these presumptions that IHL and IHRL differ most.
This analysis of necessity in IHL and IHRL was then used to develop a principled approach to reconciling these two bodies of law in certain situations. It was proposed that the constitutive function of necessity in IHL be emphasised, whilst divorcing this from the various presumptions noted above. The result is that IHRL would be seen as the default body of law and would yield to specific rules of IHL only where it was actually necessary in the prevailing circumstances. Moreover, where IHL is invoked, it was suggested that this should operate through IHRL, either by complementary interpretation or, if that is not possible, via the derogation system in human rights treaties. It was argued that this approach has a number of advantages over other proposals that have been made for reconciling IHL and IHRL. Most importantly, by encouraging a move away from the presumption that certain acts are necessary simply by reason of the threshold of armed conflict having been reached, and instead calling for IHL to be reconceived as a body of rules designed to regulate a state of necessity, this approach is much more sympathetic to the underlying object and purpose of that body of law, as shown in Section 3. Moreover, this approach would also allow us to draw on certain features of necessity in general international law and IHRL to help to develop a clear regulatory framework. It is submitted that this approach offers a solution to the interaction between IHL and IHRL that would enable the victims of conflict to benefit from the highest possible levels of protection whilst ensuring that the legal framework remains appropriate to the circumstances.
