In the wake of the events of the previous day, UN Security Council Resolution 1368 of 12 September 2001 was right to recognise ‘the inherent right of individual or collective self-defence in accordance with the Charter’. However, this does not settle the matter entirely, as in that case there was already significant evidence of a degree of responsibility of a state (Afghanistan) for the terrorist attacks. This leaves open the question of terrorist attacks in cases where there is a lack of clear evidence connecting them to a state.
On this key distinction (between terrorist attacks where there is clear evidence connecting them to a state, and where there is not), Albrecht Randelzhofer writes with a surprising degree of certainty:
Acts of terrorism committed by private groups or organizations as such are not armed attacks in the meaning of Art. 51 of the UN Charter. But if large scale acts of terrorism of private groups are attributable to a state, they are armed attack in the sense of Art 51.36
The logic of this view is a little hard to follow. It might conceivably suggest that states do not have a right of self-defence against pirates, ‘barbarians’, or armed gangs if they have no known connection with a particular state. Yet in actual cases the right of states to defend themselves against ongoing attacks, even by private groups, is not generally questioned. What is questioned is the right to take action against the state that is the presumed source of such attacks, as distinct from taking action against the on-going attack itself.
Going back to the original Charter text and to the first principles, Article 51 would appear to be open to a broader interpretation than that of Randelzhofer. Article 51 specifies neither that an armed attack has to be by a state, nor that it has to assume a conventional form.
On this matter, I cannot agree with a key part of the ICJ’s reasoning in the Wall Advisory Opinion of 2004. The ICJ Opinion discusses Article 51 in only two paragraphs; paragraph 138 and paragraph 139. In the latter of these, after quoting from Article 51, the ICJ Advisory Opinion continues:
“Article 51 of the Charter thus recognizes the existence of an inherent right of self-defence in the case of armed attack by one State against another State.”37
The ‘thus’ in that sentence is misleading: the Charter is not specific on the point that armed attack has to be ‘by one State’. The ICJ Opinion’s paragraph 139 continues:
“The Court also notes that Israel exercises control in the Occupied Palestinian Territory and that, as Israel itself states, the threat which it regards as justifying the construction of the wall originates within, and not outside that territory. The situation is thus different from that contemplated by Security Council resolutions 1368 (2001) and 1373 (2001), and therefore Israel could not in any event invoke those resolutions in support of its claim to be exercising a right of self-defence.
“Consequently, the Court concludes that Article 51 of the Charter has no relevance in this case.”38
It is surprising that the ICJ, in the only discussion of Article 51 in the entire Advisory Opinion, did not explain and justify a conclusion that seems, on the face of it, hard to square with the language of the Charter. On this specific point, i.e. regarding the scope of Article 51, the dissenting Declaration made by Judge Thomas Buergenthal is much more persuasive.
In what it says about Article 51, the ICJ’s Wall Advisory Opinion is likely to reinforce concerns that the ICJ is not as rigorous as it should be; and also that it is not knowledgeable about security issues, and has failed to understand the basic fact that states have for centuries been concerned about possible attacks by non-state entities as well as by other states.39
There are undeniably some difficulties in the position I have advanced here – namely that major terrorist attacks, whether or not they are clearly linked to a particular state, may constitute “armed attack” and therefore, by implication, may justify a military response. Most of the difficulties relate to the consequences that flow from such a position, as the following four considerations suggest:
It is not always possible to be sure from whence an attack came, or which (if any) state or states bear responsibility for it.
The exact nature of a state’s responsibility for a terrorist attack may be complex and debatable. Is a state responsible when it tried, but ineffectually, to stop activites within its borders? Or when a small faction of the government has got out of hand and encouraged activities of which the rest of the government disapproves?
Even if a victim state is fairly sure which state is responsible for the attack, the evidence that can be presented in public at the time may be incomplete; and it may be unconvincing to third parties. Thus the Libyan responsibility for the Berlin discotheque bombing in 1986 was formally established only in 2003/4, in a court case in Berlin. The US has of course taken military action against Libya already in 1986, and at the time there was some international scepticism about whether Libya was responsible, as well as about the efficacy of bombing as a response.
The historical record of wars against alleged sources of terrorism is not strong. Cases that give grounds for doubt about any kind of blanket approval of military action in purported response to terrorist attacks include Serbia 1914, Lebanon 1982, and Iraq 2003.
These four considerations need to be explicitly recognised. The conclusion to be drawn from them is that if (as I believe it should be) the concept of “armed attack” is accepted as encompassing certain types or patterns of terrorist attacks, then that should not be taken as an automatic licence to respond militarily. Any argument for military action needs to be made carefully in each case. Moreover, precisely because of the debatable character of the use of force in such cases, a multilateral response would be likely to command more legitimacy than a purely unilateral one.
As to whether an attack originating in occupied territory can constitute an “armed attack”, the core issue here is whether, when an attack emanates from an occupied territory under its control, and takes place on the territory of the occupying power, it can constitute “armed attack”. On this question, too, I consider that the case for a positive answer is strong.
Here it is again necessary to refer to the ICJ’s above-quoted paragraph 139 of the Wall Advisory Opinion. On this particular question the Court’s logic again appears flawed.
It is true that the suicide bombings with which Israel has been faced in recent years appears to have originated in the West Bank and Gaza, and that these territories have a special status, with much or all of them under Israeli occupation. This case is therefore significantly different from the assault on the USA of 11 September 2001, on which there was evidence that it originated in a foreign sovereign state. However, it is questionable to suggest or imply that there can be no right of self-defence against an attack that originates in territory in which Israel is deemed to exercise control.
In most circumstances the existence of a right of self-defence is accepted. For example, if an attack originates within a state, that state would in principle be seen as entitled in international law to take action against those launching such an attack: that is part of its prerogative as a sovereign state. Similarly, if an attack originates outside a state, i.e. in the territory of another state, then the attacked state would in principle be seen to be within its rights in taking action against it. All this raises the question as to whether the status of occupied territory is so special and unique that the right of the occupying power to self-defence is in some way significantly more restricted that the rights of governments in other situations. It is not clear that there is any such restriction in international law.
A further issue arises, which the ICJ did not discuss: whether at all relevant times the areas of the West Bank and Gaza under the control of the Palestinian National Authority should be deemed to be occupied territory. It is odd that the ICJ simply assumed that Israel exercises control over the whole of the West Bank and Gaza. It did not even consider the possibility that in certain areas of these territories its control was limited. The Palestinian National Authority is not even mentioned in the Advisory Opinion.
In conclusion, there is a strong case for asserting that terrorist actions by a non-state entity, originating in occupied territory or in a territory under a type of administration that does not constitute a fully recognised state, and aimed at the occupying power, can constitute “armed attack”. Further, such actions can at least in certain circumstances bring into play the right of self-defence. However, there is a need for extreme caution about how that right is exercised.
In my opinion, the right to exercise self-defence relates not only to an attack from another state but also to attacks from non-state actors. That point seems to me to be relatively clear, following the determination by the United Nations Security Council that the inherent right to self defence may be exercised in relation to terrorist acts40. In this regard, I regret the language adopted by the ICJ in its Wall Advisory Opinion of 2004. This part of the Opinion fails to take into account developments across the world, in particular a rise of non-state organisations which are committed to terrorist activities, an increase in the number of “failed states”, and the dangers posed by the proliferation of weapons of mass destruction.
Although certain French writers41 have argued that Article 51 concerns only responses to aggression against another state and despite one reading of paragraph 139 of the Wall Advisory Opinion, I think it clear that the right of self-defence operates with regard to attacks from non-state actors such as terrorist groups. Security Council resolutions 1368 and 1373 can only be interpreted in this light. Practice is also replete with example of terrorist groups being directly targeted. Of course, the context is critical. An attack by one state upon persons suspected of terrorist involvement in that state but present in a neighbouring state would constitute aggression/use of force where the latter is acting in accordance with normal international norms of non-intervention (e.g. IRA activists in Ireland or ETA activists in France). However, if the state subjected to the action is unable or unwilling to take measures against the terrorists, who are preparing further activities to be visited upon the target state, then action may be taken within the context of self-defence. Examples may include Southern Lebanon up to 1982 or Afghanistan in 2001.
Again, circumstances are key and the legitimacy of the action will depend upon the dangers posed by the terrorists and the failure of the state in which they are located to take appropriate action to restrain attacks upon the target state. The evolution of more and more devastating weaponry and the phenomena of rogue and failed states are both highly relevant in this context.
The phrase “from another state” carries, at least, four possible meanings.
A use of force by one state against another using conventional forces, such as in the case of the Iraqi invasion of Kuwait in 1990;
A use of force by one state, deploying armed groups or armed bands to carry out cross-border raids, against another, such as was the situation outlined in the ICJ’s Nicaragua Case;
A terrorist attack against one state planned, initiated and launched from the territory of another state that either supports or harbours the terrorist group, such as the case of the attacks of 11 September 2001 launched against the United States by groups (Al-Qaeda) believed to be operating from inside (and with the knowledge and/or support of the de facto government of) Afghanistan;
A terrorist attack against one state planned, initiated and launched from the territory of another state without that state’s approval or in the face of that state’s active (but ineffective) opposition.
The first two cases give rise to a right to use force in self-defence. The third is a little trickier. Something would depend on the gravity of the incident in question (it would have to be analogous to the use of military force by a state (Nicaragua)). But there is a further problem. The attack on America on September 11th, 2001 may have reached the level of an armed attack but the responsibility of the state of Afghanistan for that attack creates a different set of difficulties. The 2001 ILC Articles on State Responsibility42 offer some help but these were not intended to cover the question of self-defence. The ICJ gave a restrictive view of this case when it found that there was "no clear evidence of the United States having actually exercised such a degree of control in all fields as to justify treating the contras as acting on its behalf".43
In the fourth case, I would argue that there is no right under international law to use force in self-defence.
The reactions of states to the events of 11 September 2001 suggest that an operation by a non-state actor of sufficient magnitude to constitute an armed attack were it carried out by a state will be regarded as an event giving rise to a right of self-defence44. However, caution needs to be exercised in assessing the consequences of this proposition, in particular, what precisely it means for the exercise of self-defensive force by the victim state on the territory of other states, since there will be no "territory" of the actual attacker. This is to accept that, since an "armed attack" can come from a non-state actor, the notion of "attack" should embrace the same extensions mutatis mutandis as those alluded to above with respect to attacks by states. But the hard question remains: against what targets may self-defensive force be used in the event of an armed attack by a non-state actor? (See my response to question 7, below).
This question was posed starkly by the US response to the terrorist attacks on 11 September 2001. A non-state terrorist group attacked the USA, but the counter-attack was directed against the territory of Afghanistan that had provided a safe haven for Al-Qaeda. The UN Security Council in Resolutions 1368, 1373 and 1378 recognised the right of self-defence to respond to attacks of this kind. Here, the Security Council recognised that large-scale terrorist attacks could constitute an “armed attack” that gives rise to a right of self-defence. The US claimed that it was acting in self-defence in taking action against the Taliban and Al-Qaeda, with military action being undertaken to defend the United States against potential future attacks of the kind experienced in New York and Washington DC. The threat of future attacks, in the light of past attacks, justifying the claim that the USA acted pursuant to a right of self-defence.
Critics of the legality of the war in Afghanistan argue that the terrorist attacks on 11 September 2001 fail to meet the requirement of an “armed attack” because this is restricted to the use of force by states, and requires, in the words of the 1974 General Assembly’s Definition of Aggression45, activity analogous to large-scale cross-border attacks.46
Set against this, the drafters of the UN Charter did not envisage non-state violence on the scale of the events of 11 September 2001, and it is necessary for interpretations of Article 51 to evolve to meet the challenges posed by groups like Al-Qaeda. The resolutions adopted by the Council in the immediate aftermath of the 11 September attacks provide strong support for a new custom that supports a right of self-defence against states that are believed to have harboured groups who have committed attacks – and crucially, are preparing further attacks - against the territory of the state claiming the right of self-defence. What is left unclear here is whether this right to self-defence extends to anticipatory action against terrorist groups – and their state sponsors - before they have launched an attack. For example, could the US, believing there to be an imminent threat from Al-Qaeda, have reasonably claimed a right of self-defence in attacking terrorist bases in Afghanistan on 10 September, 2001?
Sir Michael Wood
States may act in self-defence in the face of a large-scale terrorist attack (actual or imminent) where the usual requirements for self-defence are met (necessity, proportionality). State practice, including the practice of the Security Council, strongly supports this position. The right of self-defence applies if the attack comes or is directed “from” outside the state exercising the right, though it may be perpetrated by non-state actors. This appears to be the underlying rationale of the ICJ in the Wall Advisory Opinion.
The ICJ dealt (at paragraphs 138 and 139 of the Wall Advisory Opinion) with Israel’s argument that “the construction of the Barrier is consistent with Article 51 of the Charter of the United Nations, its inherent right of self-defence and Security Council resolutions 1368 (2001) and 1373 (2001)”. Its treatment of this matter was subject to criticisms by Judges Higgins (paragraphs 33 to 36 of her Separate Opinion), Kooijmans (paragraphs 35 and 36 of his Separate Opinion) and Buergenthal (paragraphs 4 to 6 of his Declaration).
The Court’s analysis is succinct. After citing the first sentence of Article 51 it states, without any intervening argument, that “Article 51 of the Charter thus recognises the existence of an inherent right of self-defence in the case of an armed attack by47 one state against another state”. It then “also notes that Israel exercises control over the Occupied Palestinian Territory” and that the threat originates within, and not outside, that territory. The situation is thus different from that contemplated by resolutions 1368 and 1373.
It is difficult to know what to make of this, and in particular to deduce what the Court would have done if the situation had not been different from that contemplated in resolutions 1368 (2001) and 1373 (2001). The criticisms of Judges Higgins, Kooijmans and Buergenthal are persuasive. In particular:
(a) it seems doubtful whether non-forcible measures fall within self-defence under Article 51: see the Separate Opinion of Judge Higgins at paragraph 35;48
(b) there is no basis in the wording of Article 51 for the Court’s restriction (if such restriction was indeed intended) to an armed attack by a state. Insofar as the Nicaragua Case is authority for this49, it is not widely accepted50. It is curious that the Court did not cite the Nicaragua Judgment. Judge Buergenthal agrees with Judge Higgins on this, and as Judge Kooijmans said, at paragraph 35 of his Opinion, it is really beside the point;
(c) as Judge Kooijmans suggests, the real explanation for the Court’s approach to Article 51 in this case may be that the attack came from the Palestinian Occupied Territory. Judges Higgins51 and Buergenthal52 do not appear to accept this, considering that it was wrong to exclude self-defence for this reason since the Palestinian Occupied Territory was not part of Israel.
Eick says the following about the Wall Advisory Opinion on this point:
The ICJ first states that Article 51 of the UN Charter recognizes the right of self-defence where there is an armed attack by a state against another state; the Court then however turns to resolutions 1368 (2001) and 1373 (2001) of the UN Security Council, which precisely do not require an attack by a state for the exercise of the right of self-defence. If Israel could not call upon a right of self-defence, then this was because – otherwise than was foreseen in resolutions 1368 (2001) and 1373 (2001) – the terrorist threat did not come from outside the territory controlled itself by the state that was attacked.53
This is surely convincing. It seems that the Court was merely reflecting the obvious point that unless an attack on a state is directed from outside that state’s territory the question of self-defence does not arise. For example, the NATO decision of 12 September 2001 was to the effect that if it was determined that the attacks of 11 September were directed from abroad against the USA they should be regarded as actions covered by Article 5 of the North Atlantic Treaty54. On the facts it was questionable whether the Palestinian Occupied Territory should be assimilated to the territory of Israel for these purposes.
Turning to state practice in this field, including the recent practice of the Security Council, I can see no support for a restriction of self-defence to defence against armed attacks imputable to a state, and considerable state practice the other way. The action against Al-Qaeda in Afghanistan in October 2001 (which was widely supported and scarcely opposed by states) was action in self-defence of anticipated imminent terrorist attacks from Al-Qaeda, not from the Taliban. It was necessary to attack certain elements of the Taliban, in order to prevent attacks from Al-Qaeda. Security Council resolutions 1368 (2001) and 1373 (2001) support the view that self-defence is available to avert large-scale terrorist attacks such as those on New York and Washington on 11 September 2001. So too do the invocation by NATO and the OAS of their respective mutual defence obligations55. In his statement of 21 April 2004 in the House of Lords, the Attorney General said:
The resolutions passed by the Security Council in the wake of 11 September 2001 recognised both that large-scale terrorist action could constitute an armed attack that will give rise to the right of self-defence and that force might, in certain circumstances, be used in self-defence against those who plan and perpetrate such acts and against those harbouring them, if that is necessary to avert further such terrorist acts.56
The European Union statement upon voting in favour of General Assembly resolution ES-10/18 suggests that EU Member states and those other states associated with the statement would not accept that the armed attack must be by a state:
The European Union will not conceal the fact that reservations exist on certain paragraphs of the Court’s advisory opinion. We recognise Israel’s security concerns and its right to act in self-defence.
Russia’s statements following the school siege at Beslan likewise appear to be based upon the assumption that self-defence may be available against attacks from terrorists. The Russian Foreign Minister is reported as saying on Al-Jazeera that:
Question: Recently the Russian Defence Minister said that Russia has a right to strike blows at terrorists’ bases at any point of the world. Does his statement not contradict your assertion that it is necessary to respect international law?
Answer: It is necessary to respect international law. In particular, Article 51 of the Charter of the United Nations confirms the right of states to self-defence. The resolutions of the UN Security Council adopted after the 11th of September 2001 unanimously decreed that the right to self-defence extends not only to classical armed attacks, but also to armed attacks which are made by means of a terrorist act. Contemporary international law presumes that if a country is subjected to a terrorist attack and if there are serious grounds to assume that this attack may continue, then the state by way of the exercise of its right to self-defence can take necessary measures to eliminate or diminish such a lingering threat.
The issue of whether an “armed attack” within the meaning of Article 51 may be perpetrated by a non-state actor has been addressed in a number of academic legal analyses of the military action in Afghanistan in 2001. A range of views is expressed, but a number of them are preoccupied with the particular context of Afghanistan, rather than the more general proposition. On the one hand there are those such as Franck,57 Greenwood,58 Murphy59 and Sofaer,60 who see no difficulty in principle with the notion that non-state actors may perpetrate an “armed attack” such as to trigger the right of self-defence. Greenwood and Murphy both cite the Caroline incident itself as an early example. Verhoeven,61 Byers62 and Ratner63 each suggest that whatever may previously have been the law, following the attacks of 11 September 2001 almost all states acquiesced in the invocation by the US and the UK of the right of self-defence as the legal basis for the action in Afghanistan. In somewhat similar vein, Gray64 appears to suggest that Afghanistan should be largely confined to its facts (a massive terrorist attack, continuing threat of global terrorism by those responsible for it, the response was directed at a country which had allowed the terrorists to operate from its territory and refused to surrender them, and the findings of the Security Council contained in resolutions 1368 and 1373). Others (including Cassese,65 Charney,66 Corten and Dubuisson,67 Myjer and White68) believe that Article 51 is limited only to armed attacks committed by or attributable to a state and are therefore critical of the US reliance on self-defence as a legal basis for the action. In an article from 1989, Schachter69 suggests that there is nothing in the text of Article 51 which limits “armed attack” to acts by or imputable to a state, but finds such a limitation is implicit from the ICJ Judgment in the Nicaragua Case and earlier work of the ILC on State Responsibility70. Finally, Brunee and Toope71 require that there be a necessary link (direct support or at least tacit approval) between the target state of a self-defence action and the terrorists perpetrating the attack, although ‘states without any effective government may be an exception’.