Self-defence against terrorist attacks

International law regarding states' right to use military force in self-defence is embodied primarily in Articles 2 and 51 of the UN Charter. Article 2(4), of course, generally prohibits the use of force by states, while Article 51 carves out the most obvious exception to this rule – that of permitting states to use force in self-defence against an ‘armed attack’. In the years following the terrorist attacks of 9/11 and the ensuing US-led wars against Afghanistan and Iraq, law reviews and journals witnessed an explosion of literature on the law of self-defence, focusing on two broad issues. First, largely in response to the 9/11 attacks themselves and the subsequent invasion of Afghanistan, was the issue of whether non-state actors (that is, Al-Qaeda) could undertake an ‘armed attack’ for the purpose of Article 51, which would allow a state (the US) to use force in self-defense. The second issue, which was a response to the 2002 National Security Strategy and the build-up to war with Iraq in 2003, was whether ‘anticipatory’, or so-called ‘pre-emptive’, force was permissible to combat terrorist threats. In other words, to what extent may states use force before an attack has occurred in order to ‘pre-empt’ or avert an attack? I will address this concern first.

Anticipatory self-defence and the war in Iraq

The debate over anticipatory self-defence has been the subject of considerable controversy even before 9/11 and the ensuing ‘global War on Terror’. Article 51 of the UN Charter reads that ‘Nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a member of the UN.’Footnote ⁵ Over the past sixty years, two main ‘camps’ of legal opinion have emerged over the precise meaning of this paragraph as it pertains to anticipatory self-defence. One camp views the ‘ordinary meaning’ of the text to require that an attack has to actually happen before a state may resort to force under Article 51. Since there is no mention of a right to self-defence against a ‘threat’, or to use force in an anticipatory manner, then according to this view states may only lawfully resort to self defence if they have actually sustained an armed attack. The other camp argues that reference to the ‘inherent right’ of self-defence was an attempt to preserve previously-existing customary international law on the subject, which at the time the Charter was concluded recognised a limited right to anticipatory self-defence.Footnote ⁶ If one accepts the ‘ordinary meaning’ argument, then the discussion ends here and there is no right to anticipatory self-defence of any kind. While scholarly opinion is still very much divided on this issue, the more expansive view has gained popularity in recent years. This is partially because of the tendency of many legal scholars to view the UN Charter as an ‘a living, breathing document’ that should be read in light of not only previously existing custom, but also as responsive to new developments not contemplated when it was originally drafted.Footnote ⁷ Another reason this view has gained adherents is that forcing states to sustain a first military strike before allowing them to use force to defend themselves is to compel reductio ad absurdum.Footnote ⁸ It is difficult to imagine any state consenting to be bound by such stringent a legal rule, which casts serious doubt on whether this was truly the meaning intended by the Charter's drafters. So while many scholars continue to reject the ‘inherent right’ theory,Footnote ⁹ I shall proceed under the assumption that the Charter is at least plausibly interpreted to leave room for a limited right to anticipatory self-defence, with the controversy hinging on the degree of imminence of the attack that is to be averted.Footnote ¹⁰

The question of imminence has thus been the more controversial issue in discussions about anticipatory self-defence, which, at least until recently, has been guided by the famous Caroline doctrine. This doctrine emerged from an 1837 incident during a rebellion by Canadians against British rule, wherein the British captured and destroyed an American steamer (the Caroline) that was being used to supply the rebels on the Canadian side of the Niagara River.Footnote ¹¹ The incident, which severely strained US-British relations, culminated in a written communication by US Secretary of State Daniel Webster, wherein he outlined that the use of force in self-defence was only appropriate when the necessity of the resort to force was ‘instant, overwhelming, and leaving no choice of means, and no moment for deliberation’.Footnote ¹² In other words, the Caroline doctrine established the prevailing view that self-defence is not only permissible in response to an actual armed attack, but also when a future armed attack is imminent or already underway. It also distinguished between two species of anticipatory self defence, which are commonly (and often deliberately) conflated: Pre-emptive self-defence is that which is undertaken to thwart an attack that is imminent or underway and would be considered lawful under the Caroline doctrine. Preventive self-defence is the use of force against an actor in order to prevent it from pursuing a particular course of action that is not yet directly threatening, but if permitted to continue, might result in an armed attack at some point in the future.Footnote ¹³ Such a use of self-defensive force would not be permissible under the Caroline doctrine. I submit that among those who view the Charter to leave room for anticipatory self-defence, this was the prevailing view when the ‘global War on Terror began’.Footnote ¹⁴

Two interrelated developments in the global War on Terror once again brought these age-old concerns front and centre among international law scholars: the 2002 National Security Strategy and the 2003 invasion of Iraq. In September 2002, barely a year after 9/11 and the war in Afghanistan, the Bush Whitehouse issued the National Security Strategy (NSS), which, in addition to a speech delivered in June of that year at West Point, famously constituted what became known as the ‘Bush Doctrine’.Footnote ¹⁵ The pertinent part of the Bush Doctrine outlines that the US ‘will not hesitate to act preemptively against terrorists [in order] to prevent them from doing harm against our people and our country’.Footnote ¹⁶ The choice of words here is crucial, as the language specifically refers to pre-emptive self-defence, which, considering the imminence criteria suggested above, was widely recognised to be permissible under international law. The NSS indeed recognised this reality, and also deliberately set out to change this legal standard when it stated that ‘[w]e must adapt the concept of imminent threat to the capabilities and objectives of today's adversaries’.Footnote ¹⁷ Thus, the argument seemed to be that while the legitimacy of pre-emption used to be conditioned on the visible mobilisation of armies and other forces preparing to attack, in an age of terrorists armed with weapons of mass destruction (WMD), the standard of imminence must evolve. The standard must be relaxed, so the argument goes, because a terrorist attack with a nuclear weapon would entail no such warning. While the Bush administration used the language of pre-emption during the drumbeat toward war with Iraq during the autumn of 2002, it was actually touting a much more permissive concept of self-defence akin to prevention, as described above. The use of force against Iraq was therefore argued to be necessary to prevent a future threat from materialising, in order to ‘take the battle to the enemy, disrupt his plans, and confront the worst threats before they emerge’.Footnote ¹⁸ Since Iraq was thought to have WMD, ties with terrorists, and the proclivity to either use WMD against the US or relinquish them to terrorists who would, this revised notion of anticipatory self-defence played a prominent role in public justifications for the invasion.

The question, therefore, is whether the US's assertion of this expanded right to self-defence, its apparent implementation in the 2003 invasion of Iraq, and the various reactions of other states to this development, can be said to affect the formation of a new customary rule that effectively relaxes the imminence and necessity requirements outlined in the Caroline doctrine in light of the fundamentally different threat posed by terrorists. Mark Drumbl has argued that these developments have indeed contributed to the development of such a rule, pointing to the active support of many other states in the invasion and occupation of Iraq, as well as the endorsement by the UN of the US and UK as occupying powers there.Footnote ¹⁹ While a comprehensive analysis of state practice on this issue is beyond the scope of the present article, there are at least two reasons to be sceptical that such a permissive rule has emerged or is in the process of developing.

The first reason has to do with the fact that the Iraq invasion has at various points been characterised as no fewer than three different varieties of armed conflict – both terms of in public justification by US officials, as well as the various legal arguments in favour of it. Was the Iraq invasion an act of (anticipatory) self-defence by the US, a UN-authorised enforcement operation, or a humanitarian intervention? All three of these justifications have at some point been advanced by US officials in both public fora and by legal analysts defending the legality of the war.Footnote ²⁰ For this invasion to count as state practice that contributes to a customary rule that accepts the legitimacy of preventive self-defence, there must be evidence that the US and other key states involved in the invasion believed that it was legal on this basis. If this were the case, one should expect the US, the UK, and Australia (the primary invading states), to assert this right for this particular operation in their official letters to the UN Security Council (UNSC).Footnote ²¹ However, in all three of these states' letters to the Security Council, the legal justification given for the invasion was that of enforcing various UNSC resolutions.Footnote ²² The actual legal argument advanced for the war in Iraq was therefore a UN-authorised enforcement operation pursuant to Iraq being found in material breach of the ceasefire resolution that ended the 1991 Gulf War (Res. 687), thus re-activating the 1990 UNSC resolution (Res. 678) that authorised the use of force for the first Gulf War. The self-defence argument was one that was generally directed toward the public, which, as many critics of the war argued, exploited the fear of the American people after 9/11 and deliberately sought to conflate the alleged Iraqi WMD threat with terrorism and the perpetrators of 9/11.Footnote ²³

Of course another argument that was probably more for public consumption than an actual legal position was that the invasion was a humanitarian or otherwise ‘liberal’ intervention that sought to remove a brutal tyrant from power and establish democratic institutions in Iraq. Again, however, given that this was not the legal position espoused by the relevant states (and the fact that this argument became most prominent only after the failure to find WMD or links with terrorists), there is little reason to afford this argument meaningful legal significance toward creating a customary law exception for humanitarian intervention.Footnote ²⁴ While it is true that the assertion of a more permissive right to self-defence was espoused in a broad, doctrinal way – which does seem to be an assertion of a legal doctrine as opposed to a political policy – the fact that this doctrine was not the basis of the official legal position advanced for the invasion militates against its inclusion as state practice relevant to the creation of new custom on the issue of anticipatory self-defence.

Admittedly, much of this discussion hinges on what is appropriately considered ‘state practice’ for the purposes of ascertaining customary international law – that is, do verbal assertions of certain legal rights count or do we need actual implementation of such rights in practice? While most legal scholars suggest that such pronouncements do have legal consequences, actual practice seems to be the more decisive basis of customary international law, while verbal pronouncements do constitute evidence of what a state does.Footnote ²⁵ There is nevertheless a certain incongruence between the rights asserted in the Bush Doctrine and the legal argument actually advanced for the Iraq invasion, which suggests a rather weak basis for concluding that this event contributes to new custom pertaining to anticipatory self-defence. Furthermore, the fact that the US and its allies did not expressly invoke an anticipatory self-defence as a legal position indicates the doubtful status of this justification and is evidence that these states did not believe the invasion would be legal on this basis, which would indicate a lack of opinio juris.Footnote ²⁶

Second, even if we assume that this invasion is state practice that is relevant to the law of anticipatory self-defence, and accepting that the reactions of other states to this war can also affect the formation of new custom, the widespread opposition to the invasion by many (if not most) states must be considered alongside any analysis of the state behaviour generally thought to be supportive of the invasion. It is true that many Eastern European states, along with Japan, Israel and South Korea, verbally supported the US, and as many as 40 countries contributed troops to the occupation.Footnote ²⁷ However, there is little to suggest that these states were endorsing, as a matter of legal principle, the invasion as an act of preventive self-defence without UNSC approval. Likewise, the UNSC's endorsement of the US and UK as occupying powers responsible for the well-being of post-invasion Iraq should not be read as anything other than a formal acknowledgement of the reality on the ground, and certainly does not indicate support for the invasion as an act of preventive self-defence.Footnote ²⁸ Even so, the most important piece of evidence is that most states of the world simply did not support the invasion, suggesting that the war was a simply a violation of international law, rather than state practice indicative of an emerging change in the law.Footnote ²⁹

In sum, the fact that the legal positions of those governments who spearheaded the 2003 Iraq invasion were that this invasion was, legally-speaking, a UN-authorised enforcement operation, suggests that the invasion should not be considered as part of state practice contributing to an emerging customary rule relevant to anticipatory self-defence. Furthermore, the fact that most governments of the world opposed the invasion, and those that supported it did not do so on the basis of an emerging norm of preventive self-defence, provides further evidence for this conclusion. This is not to deny that some states – such as the US, Russia and Indonesia – in principle, advocate the use of preventive force against terrorists and state sponsors of terrorism.Footnote ³⁰ However, the assertion of a legal right in the abstract does not carry the same legal weight as an actual exercise of the alleged right, which, if my argument is correct, was not done in the 2003 Iraq invasion. Another incongruity between the rights asserted in the Bush Doctrine and the circumstances surrounding the Iraq war is that we now know that there was no meaningful connection between Iraq and the terrorists who perpetrated 9/11, and that the Al-Qaeda elements fighting coalition troops in Iraq appeared well after the initial invasion.Footnote ³¹ Thus, the notion that the Iraq war somehow constitutes preventive self-defence against a terrorist threat is not born out by the facts. The Iraq war is therefore not appropriately considered state practice of anticipatory self-defence, and especially not anticipatory self-defence against terrorists. The most that can be said for the time being is that some states are asserting an expanded right to anticipatory self-defence against terrorists, but that such a practice has not been sufficiently undertaken or supported to indicate the emergence of new custom.

State-sponsored terrorism or non-state ‘armed attack’? The Afghanistan war

The concern of whether the Iraq invasion was a war against terrorists or a war against a state (or against both) matters if one is appraising the effects that the use of force against terrorist threats is having on international law. Clearly, the Iraq war had elements of counter-terrorism, but the link between terrorists and the state of Iraq was extremely negligible, which was probably another reason the US and its allies did not rely on a self-defence argument or to try and formally attribute the 9/11 attacks to Iraq (even though many government statements implied as much). It was the 2001 US war in Afghanistan that provided a clearer example of the self-defensive use of force against terrorists, although not in an anticipatory manner. Unlike the Iraq invasion two years later, the war in Afghanistan was much more easily justified as a war of self-defence, whereby instead of having to potentially rely on a doctrinally uncertain right to anticipatory self-defence, the US could more plausibly claim that the 9/11 attacks were an ‘armed attack’ under Article 51. Thus, the potential effect of the invasion of Afghanistan on international law has to do with the concept of ‘armed attack’ – specifically, whether a non-state terrorist group can undertake an ‘armed attack’ that would trigger a state's right to use force under Article 51, as well as the degree of state involvement that must be present in such an attack.

The primary legal question dealt with by scholars and analysts after the 9/11 attacks and the US invasion of Afghanistan was whether an attack by a non-state actor may be considered an Article 51 armed attack, and if not, what degree of state involvement is required. It is on this issue where one finds a potential effect on the law, and there seems to be a fairly broad consensus among legal scholars that the response of the international community to 9/11 has, at the very least, left its mark on the law.Footnote ³² As is well-known, the attacks against the US on 9/11 were undertaken by the Qaeda terrorist organisation and planned from within the state of Afghanistan, which was at the time ruled by the Taliban regime. The underlying rationale for the impending US response to this attack was made clear the very same day as the attacks, when President George W. Bush said that the US would ‘make no distinction between the terrorists who committed these acts and those who harbour them’.Footnote ³³ Less than a month later, the US informed the UN Security Council that, in accordance with Article 51 of the UN Charter, it was commencing military operations ‘against Al-Qaeda terrorist training camps and military installations of the Taliban regime in Afghanistan’.Footnote ³⁴ In its letter, the US characterised the 9/11 attacks as ‘armed attacks’ that were carried out by Al-Qaeda, which was ‘supported by the Taliban regime in Afghanistan’.Footnote ³⁵

There is nothing in the plain text of Article 51 that requires the exercise of self-defence to rely on whether an armed attack was committed by a state or a non-state actor. However, at least before 9/11, the predominant view among scholars, jurists, and statesmen appeared to be that self-defence is only justified if the attack is attributed to a state, with the controversy centring on the standard for attributing state responsibility for the attack.Footnote ³⁶ The International Court of Justice (ICJ) has even appeared to assume that a state must be involved in an armed attack. Citing the Article 3(g) of the UN General Assembly's 1974 Definition of Aggression, the ICJ in the Nicaragua case held that an ‘armed attack’ for the purposes of Article 51 includes the dispatch by a state of armed bands or ‘irregulars’ into the territory of another state.Footnote ³⁷ The Court further held, however, that it did not believe that ‘the supply of arms and other support to such armed bands’, including the ‘provision of weapons or logistical or other support’, qualified as an armed attack.Footnote ³⁸ In determining whether the acts of a non-state may be attributed to a state, the issue in Nicaragua was thus ‘the degree of dependence on the one side and control on the other’ that would equate non-state armed groups with the organs of a state or as acting on behalf of a state.Footnote ³⁹ The standard that emerged was one of ‘effective control’ of the activity by the state in question.Footnote ⁴⁰ The jurisprudence flowing from Nicaragua therefore suggests that actions by non-state actors can indeed constitute an armed attack for the purposes of Article 51, but only if the non-state is sufficiently under the control of a state, which must go beyond the mere provision of supplies, arms, or logistical support. Rather, the state must have effectively sent the non-state to undertake the attack on its behalf. This general standard of attribution has been reiterated by the ICJ in the Wall advisory opinion and in DRC v. Uganda, reaffirming the Court's position that armed attacks giving rise to the right to self-defence must be imputable to a foreign state.Footnote ⁴¹ The International Law Commission's (ILC) Draft Articles on State Responsibility likewise confirm the rather high threshold for attribution, providing that such actions may be attributed to the state if the entity ‘is acting on the instructions of, or under the direction or control of, that state in carrying out the conduct’.Footnote ⁴²

The degree to which the Taliban exercised ‘effective control’ over Osama bin Laden and Al-Qaeda is an empirical question, yet reports suggest that Al-Qaeda was not under the control of the Taliban government, therefore not satisfying the ‘effective control’ test articulated in Nicaragua.Footnote ⁴³ Yet despite falling short of the heretofore authoritative ‘effective control’ test for state attribution, the various legal measures taken by international bodies and the responses of a vast majority of states militate strongly in favour of the legality of the US resort to force under Article 51. In response to the attacks, the UN Security Council adopted resolutions 1368 and 1373, both of which recognised and reaffirmed in this context ‘the inherent right of individual or collective self-defense in accordance with the Charter’.Footnote ⁴⁴ Likewise, the North Atlantic Council, NATO's policymaking organ, invoked Article 5 of the Washington Treaty the day after 9/11, which deemed the attack against the US an attack against all NATO members.Footnote ⁴⁵ Article 5 uses the expression ‘armed attack’ and does so explicitly in the context of Article 51 of the UN Charter. For its part, the Organization of American States (OAS) adopted a similar resolution that recognised the right to self-defence under Article 51 and stated that ‘those responsible for aiding, supporting, or harboring the perpetrators of [9/11] are equally complicit in these acts’.Footnote ⁴⁶ The EU (EU) also declared its ‘wholehearted support for the action […] undertaken in self-defense in conformity with the UN Charter and UNSC Resolution 1368’.Footnote ⁴⁷ Perhaps most compelling were the responses of states, which were nearly unanimous in supporting – or at least abstaining from criticising – the US military campaign.Footnote ⁴⁸ It therefore seems clear based on the international reaction that most states and international bodies were willing to accept the legality of the US's use of force as an act of self-defence in response to the attacks of 9/11.

The international reaction to the 9/11 attacks and the widespread support of the subsequent US invasion of Afghanistan in self-defence suggest that international law may be evolving in a way that recognises a broader right to self-defence by states.Footnote ⁴⁹ Two interrelated legal developments are at issue. The first is that the nexus between the ‘harboring’ state and the non-state actor need not be one of ‘effective control’ for acts of the latter to be attributed to the former. This would permit – as in the case of the US invasion of Afghanistan – the use of defensive force to be directed against the state in whose territory the non-state actor is operating on the basis of an eased nexus requirement – perhaps a standard of ‘harboring’ versus ‘effective control’. The second potential development is that terrorist groups may be said to undertake an ‘armed attack’ independent of any nexus to a state, which is a far more radical development and potentially indicates the emergence of a regime of ‘non-state responsibility’.

The applicability of IHL to terrorist groups

The accountability of non-state actors under the laws of war is perhaps more clearly dealt with by IHL – specifically, the Geneva Conventions of 1949 and their two Additional Protocols of 1977. While it is true that traditionally, international law only recognised states as participants in armed conflict, and the Geneva Conventions as a whole only apply to situations of ‘armed conflict’ among two or more states that are party to the conventions, the conventions and their protocols have specific provisions that apply to conflicts between states and armed opposition groups, as well as conflicts among such groups.Footnote ⁷³ Furthermore, these instruments provide for individual criminal responsibility for violations of the provisions therein, thereby exemplifying the post-war precedent established at the Nuremburg trials, which established that individuals, and not just states, can be held accountable for violations of international law. It generally uncontested that individuals have rights and can be held accountable under these treaties, but a more difficult question is whether certain individuals have these rights and duties pursuant to their membership in a group that is a party to an armed conflict, and whether such groups are even legally capable of being a party to an armed conflict. So while a substantial portion of the legal scholarship in the immediate aftermath of the US invasion of Afghanistan focused on the legal status of captured Al-Qaeda (and Taliban) fighters, and whether IHL applied to them as individuals,Footnote ⁷⁴ I am presently concerned with the overall legal status of Al-Qaeda as a group to which IHL potentially applies, thus potentially indicating an extension of international legal personality to previously unrecognised subjects of international law.

IHL and non-state actors in general

Since non-state armed groups are not states, and therefore cannot be party to the Geneva Conventions or their Additional Protocols, the Geneva Conventions writ large only apply in situations of armed conflict between two or more state parties to the treaties – a situation formally known as an ‘international armed conflict’. There are a couple of exceptions to this, however. First, Additional Protocol I recognises ‘liberation movements’ as potential parties to an armed conflict ‘in which people are fighting against colonial domination and alien occupation and racist regimes in their exercise of their right to self-determination’.Footnote ⁷⁵ In other words, political communities that are not states – but which presumably aspire to statehood and have a certain degree of internal organisation – that take up arms to resist colonialism or other unjust occupation, may be considered parties to an international armed conflict on equal footing with state parties if they make a declaration to this effect.Footnote ⁷⁶

Second, and more relevant for present purposes, Additional Protocol II and Common Article 3 to the Geneva Conventions apply to conflicts between a state and ‘armed opposition groups’, or conflicts among such groups, as long as the conflict takes place in the territory of a state party to the conventions. These two instruments lay out a set of rules intended to apply in ‘armed conflicts not of an international character’, and are widely considered to be binding on armed opposition groups and their individual members.Footnote ⁷⁷ For both instruments, however, a set of conditions applies that the opposition group must meet in order to be considered a ‘party’ to a non-international armed conflict for the purposes of IHL, which confers upon it status as a legal entity. Under these instruments as interpreted by authoritative bodies, the non-state party must be able to carry out protracted hostilities, must be capable of identification as a party to the conflict, and must be sufficiently organised so as to be able to impose internal discipline upon its members, which indicates the ability to apply and enforce the rules of IHL among its ranks.Footnote ⁷⁸ While control of territory is also a requirement under Additional Protocol II, international tribunals have not interpreted such a requirement for the application of Common Article 3.Footnote ⁷⁹

So for non-state actors to be considered parties to an armed conflict to which IHL applies requires firstly, the existence of armed hostilities that go beyond ‘situations of internal disturbances and tensions, such as riots, isolated and sporadic acts of violence’,Footnote ⁸⁰ and secondly, that the non-state demonstrate certain objective characteristics having to do with internal organisation, identifiably as a cohesive group, and so on. While difficulties abound in determining whether certain situations in fact cross these thresholds of violence and non-state organisation, a prima facie application of these rules to the US global War on Terrorism – specifically the war against Al-Qaeda in Afghanistan – suggests that Al-Qaeda does not meet these requirements, thus they should not be considered a party to an armed conflict for the purposes of IHL.Footnote ⁸¹

There are a number of reasons why many legal scholars have reached this conclusion. One reason is that, at least until recently, terrorist acts by private groups have not been viewed by states as initiating an armed conflict for the purposes of IHL.Footnote ⁸² This, of course, was desirable for states that did not want to be bound by IHL in their efforts to combat terrorism, such as the British efforts against the IRA and Spanish operations against ETA. Yet the 9/11 attack was different than these situations in that it was directed from abroad and it was a much larger-scale and more coordinated attack than past terrorist attacks. It is therefore reasonable to conclude that the scale and severity of the 9/11 attacks did cross the threshold of intensity so as to be distinguished from sporadic or isolated acts of violence.Footnote ⁸³ While there is disagreement on whether the supposed armed conflict with Al-Qaeda began on 11 September with the terrorist attacks, or on 7 October with the US invasion of Afghanistan, one can at least conclude that levels of violence were sustained enough to constitute an armed conflict by the time the US invaded, if not actually on 11 September.Footnote ⁸⁴

The decisive test, however, is whether Al-Qaeda possesses the characteristics of an armed group under IHL such that it could be party to an international or non-international armed conflict. It seems extremely unlikely that Al-Qaeda could be considered a ‘liberation movement’ engaged in a struggle for self-determination for the purposes of Additional Protocol I, which would put it on equal legal footing with a state party in an international armed conflict. While one could argue that Al-Qaeda acted under the authority of the state of Afghanistan, thereby attributing the 9/11 attacks to a state and invoking the Geneva Conventions writ large, Al-Qaeda was not sufficiently under the control of the Taliban for the purposes of attribution.Footnote ⁸⁵ Regarding non-international armed conflict under Additional Protocol II and/or Common Article 3, given that Al-Qaeda is not organised hierarchically, but as a network of loosely connected operational and support cells, it is highly doubtful that Al-Qaeda has a sufficiently identifiable scope and membership, sufficient organisation and structure, and the capability to abide by IHL. Thus, based on the analysis so far, Al-Qaeda would not posses the characteristics to be considered a party to an armed conflict to which IHL would bind them as a group. Yet more recent events may be signalling a new direction for future legal developments.

US Practice and the Supreme Court in the Hamdan Case

In the aftermath of the 9/11 attacks, President Bush referred to them as an ‘act of war’, declared a state of emergency, sought war powers and an authorisation of force from Congress, and eventually authorised military commissions to try personnel detained during this war.Footnote ⁸⁶ Thus, the position of the US was that in addition to constituting an ‘armed attack’ for the purposes of Article 51 of the UN Charter, the 9/11 attacks also initiated an ‘armed conflict’, yet it was argued that the prisoner-of-war (POW) protections of the Third Geneva Convention would not extend to either Taliban or Al-Qaeda fighters once captured.Footnote ⁸⁷ While the US eventually changed its position and concluded that the Geneva Conventions applied to the conflict with the Taliban because Afghanistan was a state party to the conventions, it continued to deny that the conventions applied to Al-Qaeda personnel because it is a non-state actor and not party to the conventions.Footnote ⁸⁸ The US administration likewise concluded that Common Article 3, which sets forth the minimum protections in conflicts ‘not of an international character’, did not apply to either of the conflicts because the conflicts were ‘international in scope’.Footnote ⁸⁹Al-Qaeda personnel captured in the context of the War on Terror were therefore considered ‘unlawful combatants’ and not granted substantive rights under the Geneva Conventions. The US position therefore held that the conflict with Al-Qaeda was an ‘armed conflict’ legally speaking, but one that, because of its special circumstances, fell between the cracks of the Geneva Conventions.

Most commentators on the Geneva Conventions – including the ICRC – are of the view that no persons fall outside the conventions' protections, and that if Al-Qaeda personnel are not protected as combatant POWs, then they are perforce civilians who benefit from the protection of the Fourth Geneva Convention because they ‘find themselves […] in the hands of a party to the conflict’ – that being the international armed conflict between the US and Afghanistan.Footnote ⁹⁰ Yet the US claimed that members of Al-Qaeda were ‘unlawful combatants’ that essentially have the disadvantages but not the benefits of the conventions. That is, they do not receive any of its protections if detained, but can still be attacked as combatants on the battlefield and detained for the duration of the conflict without any determination as to their individual status.Footnote ⁹¹

Many of these practices of the US government were called into question by the US Supreme Court in the Guantanamo cases.Footnote ⁹² While each of these cases has as much or more to do with US constitutional law as international law, one case in particular – Hamdan v. Rumsfeld – has direct implications not only for the status of Al-Qaeda detainees, but for the status of the conflict between the US and Al-Qaeda. While an exhaustive discussion of the Hamdan case is beyond the scope of the present article, the basic facts are as follows. Salim Hamdan – alleged to be Osama bin Laden's driver and bodyguard – was captured in Afghanistan shortly after the US invasion, sent to Guantanamo Bay, charged with conspiracy to commit terrorism, and scheduled to be tried by a military commission. After his petition went through US district and circuit courts, the Supreme Court eventually ruled in June 2006 that Hamdan's trial by military commission did not comply with the minimum procedural requirements of Common Article 3, which the US was obliged to follow.Footnote ⁹³ The court concluded that the war between the US and Al-Qaeda is covered by Common Article 3 as a ‘conflict not of an international character’ because this term is to be taken literally to mean any conflict that ‘does not involve a clash between nations’.Footnote ⁹⁴

There are a couple of points raised by this ruling that are worth emphasising. The first is that the ruling seems to confirm the view that Common Article 3 is not limited in its application to ‘internal’ conflicts and can apply even when a conflict is ‘transnational’ in nature. As one commentator put it, ‘[non-international] conflicts are distinguished from international armed conflicts by the parties involved, rather than by the territorial scope of the conflict’.Footnote ⁹⁵ Second, the fact that the Supreme Court concluded that Common Article 3 applies to the US conflict with Al-Qaeda implies that it considers Al-Qaeda to be a party to a non-international armed conflict and therefore an addressee of IHL.Footnote ⁹⁶ The logic is as follows. For IHL (Common Article 3) to apply, there has to be a (non-international) armed conflict, and for there to be an armed conflict, there must be identifiable parties. It is true that IHL can apply to individuals who are not members of a party to an armed conflict, but for the present situation this would require the court to have found that Hamdan was captured pursuant to the international armed conflict between the US and Afghanistan, which would grant him protections under the conventions writ large (specifically the Fourth Convention). Since the court based its ruling on the existence of a separate armed conflict between Al-Qaeda and the US, however, it was effectively saying that IHL applied to this conflict independently of its relationship to the armed conflict between the US and Afghanistan.Footnote ⁹⁷ And since Common Article 3 explicitly states that it applies to ‘each party of the conflict’, a finding that it applies to this conflict means that Al-Qaeda is ipso facto bound by its provisions as much and as equally as the US. Thus, Al-Qaeda as a group is a party to an armed conflict with the US to which IHL applies and has international legal personality as such.

The basis of the court's ruling in Hamdan – that Al-Qaeda is a party to an armed conflict with the US – is consistent with the view of the US (and Al-Qaeda for that matter) that they are involved in an armed conflict with one another,Footnote ⁹⁸ but it also seems to break new ground in the application of the laws of war to non-state actors. By deeming Al-Qaeda as a party to an armed conflict, the court is contradicting substantial state practice and scholarly opinion that suggests non-state terrorist organisations lack legal personality and therefore cannot be party to armed conflicts for the purpose of IHL, precisely because of their lack of organisational structure, clear membership, or ability to comply with IHL.Footnote ⁹⁹ Not only have states been extremely reluctant to grant international status to non-state armed groups, in general, for fear of encroachment on state sovereignty, but many also fear that applying the language of IHL to the activities of especially terrorist organisations may serve to confer inappropriate legitimacy on what are essentially international criminal organisations.Footnote ¹⁰⁰ Such a conclusion particularly seems to be without regard for the organisational characteristics that such groups must possess in order to constitute parties to a conflict, legally speaking. What, then, is the basis of the court's conclusion in this regard?

The Supreme Court in Hamdan did not undertake an analysis of the characteristics that a non-state group must possess to be considered a party to an armed conflict, so if a new legal norm is indeed emerging that treats terrorist groups such as Al-Qaeda as parties to an armed conflict largely irrespective of their organisational character, its basis is a matter of speculation. One could reasonably conclude, however, that if it is not the organisational characteristics that matter, then it is their de facto engagement in armed hostilities on an international and substantial scale. This would essentially mean that the factor driving Al-Qaeda's status as a party to an armed conflict was its demonstrated ability to undertake large-scale violent acts on a global scale. This would certainly dovetail with the basis for considering attacks by non-state actors as ‘armed attacks’ for the purposes of Article 51 of the UN Charter, as argued above. It would also be consistent with the view of the ICRC articulated in 1998 that the ‘scope and application [of Common Article 3] must be wide as possible and should not be limited by unduly formal requirements’.Footnote ¹⁰¹ Thus, while perhaps not reflecting the law as it currently stands, the notion that terrorist groups can, in principle, be parties to armed conflicts is increasingly reflected in international practice; and at least for the present case, Al-Qaeda's status as a party to an armed conflict with the US seems to be settled.