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Summers, James --- "The right of self-defence: Against whom?" [2005] NZYbkNZJur 3; (2005) 8.1 Yearbook of New Zealand Jurisprudence 33

Last Updated: 12 April 2015

The Right of Self-Defence: Against Whom?



The 11 September attacks and the subsequent US invasion of Afghanistan have raised profound questions about the scope of the right of self-defence in international law, in particular, to whom it applies. The United States has asserted that it has a right of self-defence against attacks by the Al-Qaeda terrorist organisation. However, this would seem to depart from what might be called the "traditional" interpretation of self-defence, which limits the right to between states. In this view, both the perpetrator and the victim of an "armed attack", which gives rise to a right of self-defence, can only be a state. Yet this view itself has somewhat uncertain foundations, not being spelled out in the main provision on self-defence in the UN Charter and instead derived from a custom which shows some notably inconsistent practice. How, then, should the right of self-defence be considered? Is it reserved only for states, or can it also relate to other actors, such as terrorists, peoples and even individuals?

The starting point for self-defence in contemporary international law is article 51 of the UN Charter 1945. This provides that: "Nothing in the present Charter shall impair the inherent right of self-defence if an armed attack occurs against a Member of the United Nations..." A notable omission here is that article 51 refers only to an armed attack and not specifically an attack by a state. Another significant feature of the article is that it is framed as an exception, an inherent right that is unaffected by other provisions of the Charter. That provision, of course, is article 2(4), which lays down the general prohibition of the threat or use of force against the territorial integrity or political independence of any state. Article 51 is, in fact, one of two exceptions to article 2(4), the other being the use of force sanctioned by the

Dr. James Summers, Law School, University of Lancaster, UK

UN Security Council under article 42. Of these two exceptions, article 51 undoubtedly gives individual states the most power, as opposed to the rather elitist article 42 which leaves matters to the Security Council and the consent of the P5 powers. The exercise of self-defence is not entirely left to states. Article 51 also provides that member states have a duty to report to the Security Council. Nonetheless, when states have sought to challenge and pick holes in the general prohibition on the use of force in article 2(4), article 51 has usually been the provision of choice.

And pick holes they have. Challenges to article 2(4) have come from doctrines like humanitarian intervention1 and self-determination,2 which look like rather like the just war doctrine that article 2(4) was intended to replace, as well as doctrines of intervention determined by the strategic considerations of the Cold War.3 However, the UN Charter itself also rests on a particular strategic vision and it is argued here that the law of self-defence is the product of the interaction between various strategic considerations within the medium of international law.

On one hand, traditional view of self-defence is based on an "international" inter-state conflict between the regular armies of states. This reflects the basic scheme of the UN Charter which seeks to generally prohibit the threat or use of force between states. It also corresponds with the general strategic interest of states in the prohibition of such a use of force, especially small, weak and vulnerable states.' This

See Thomas M. Franck and Nigel S. Rodley, "After Bangladesh: The Law of Humanitarian Intervention by Military Force" 67 AJIL (1973) pp. 275-305.

  1. See Michla Pomerance, Self-Determination in Law and Practice: The
    New Doctrine of the United Nations (Martinus Nijhoff, The Hague, 1982) at p. 48.


See W. Michael Reisman, "Old Wine in New Bottles: The Reagan and Brezhnev Doctrines in Contemporary International Law and Practice" 13 Yale Journal of International Law (1988) pp. 171-198. See e.g. Singapore: "Because we are small and because we are military weak, we therefore have a major stake in the efficiacy of international law, in the principles of the Charter of the United
2005 The Right of Self-Defence: Against Whom? 35

interpretation also works well in international law as a medium. International law is essentially state-orientated, in that it broadly derives from the intentions and practice of states, and its rights and obligations are usually connected in some way to states. Thus, a right between two states is one for which international law is well suited.

On the other hand, other strategic interests have emerged. The UN era has seen the growth of unconventional warfare involving non-state actors — terrorists, national liberation movements, peoples — and these may be the focus of states' strategic interests, either as threats or as allies. These states may correspondingly wish to see the law regulating the use of force address those groups. However, unlike the general interest of states in seeing force prohibited in international relations, these interests may vary between states. One state may be the target of what it might call a "terrorist" group, while another may support that "liberation movement". States also vary in their capacities. There are few states, for example, with the capability to intervene in defence of their nationals anywhere in the world, and, correspondingly, one might expect relatively few states to raise this particular entitlement.' In terms of international law, non-state actors, like "terrorists" or "peoples" may also be difficult to define and not lend themselves well to legal formulation. A law that encompasses such concepts might seem dangerously vague and political — all too easily open to abuse.

However, international law as a medium, while creating difficulties for non-state strategic interests, also creates opportunities. Key areas of the law of self-defence are not spelled out. As has been noted, article 51 does not specify

Nations and in the United Nations collective security system." S/PV.2487, para. 406.

See Derek W. Bowett, "The Use of Force for the Protection of Nationals Abroad" in Antonio Cassese ed., The Current Legal Regulation of the Use of Force (Martinus Nijhoff, Dordrecht, 1986) pp. 39-55 at p. 41.

that an attack has to be by a state.° The task of filling in that particular detail has been left for custom. But, interpreting custom itself can be something of an art form. What is the relevant practice and opinio juris and how much is relevant? If there is competing practice in the interpretation of self-defence, when one looks at new interpretations, does one see the glass as half full or half empty?


If the inter-state interpretation of self-defence was not spelled out in article 51, this omission was filled in by the International Court of Justice in the Nicaragua (Nicaragua v. United States) Case. The Court specified that self-defence was a right exercised between states. Significantly, the context for the ICJ's 1986 judgment was unconventional warfare. The case, in part, concerned American involvement in supporting the Contra rebels fighting the left-wing Sandinista government in Nicaragua. The United States, in turn, claimed that it was acting in collective self-defence against Nicaragua's support for rebel movements in El Salvador and other Latin American countries.

The question was, then, whether the actions of a guerrilla group could constitute an "armed attack" under international law. The Court considered that it could, if the on the basis of its, "scale and effects", the guerrilla action, "would have been classified as an armed attack... had it been carried out by regular armed forces."' However, in other regards, the Court's approach to unconventional warfare was more conventional. While an armed attack could be carried out by "armed bands, groups, irregulars or mercenaries", they had to be sent, "by or on behalf of a State... against another State".s

  1. The phrase "armed attack" was left undefined in the UN Charter. See Ian Brownlie, International Law and the Use of Force by States (Clarendon Press, Oxford, 1963) at pp. 278-9.

7 Military and Paramilitary Activities In and Against Nicaragua (Nicaragua v. United States of America) (Judgment), ICJ Reports (1986) p. 103, para. 195.
8 ICJ Reports (1986) p. 103, para. 195.
2005 The Right of Self-Defence: Against Whom? 37

This echoed article 3(g) of the General Assembly's 1974 Definition of Aggression, GA Res. 3314(XXIX), which similarly refered to the sending of armed bands "by or on behalf of a State".9 The activities of armed non-state actors could entail legal consequences only to the extent that they could be imputed to a state. In this regard, the Court used quite a tight test of "effective control" over a group to establish this responsibility. It was not enough that a state was involved in the, "financing, organizing, training and equipping", of a guerilla group or even, "selection of... military or paramilitary targets, and the planning of the whole... operation". Not even the "general control" of a state over a group or "a high degree of dependency" of the guerillas on the state, necessarily entailed responsibility. State responsibility was only involved if a state "directed or enforced" the particular actions of a guerrilla group.' The test has been loosened up in later jurisprudence, in particular, in the ICTY's broader test of "overall control" over a non-state group." Nonetheless, the focus has remained on a situation in which a state exercises such control over a group that its members can be considered, "de facto State

Thus, guerilla actions could only constitute an armed attack if they were of a sufficient scale and effect, and if a state was exercising control over that movement. The Court was quite specific that, "assistance to rebels in the form of the provision of weapons or logistical or other support", even though it could be considered to be a threat or use of force, or intervention, did not itself amount to an "armed attack".' However, these tests of scale and control, which were integral to a narrow inter-state view of self-defence, also left significant gaps in the law of armed conflict, a fact noted by


GA Res. 3314(XXIX), 29 GAOR (1974) Supplement No. 31, (A/9631) pp. 142-4.
to ICJ Reports (1986) p. 64, para. 115.

Prosecutor v. Dusko Tadic (Appeals), IT-94-1-A (1999) paras. 98

12 Ibid. para. 98.
13 ICJ Reports (1986) p. 104, para. 195.
38 Yearbook of New Zealand Jurisprudence Vol 8.1

judges Schwebel" and Jennings' in their dissenting opinions. Indeed, this gap seems to create a certain impunity for low intensity guerilla warfare.' As a political matter, however, it can be questioned whether states would tolerate such attacks. There is also the issue that if non-state actors could organise attacks equivalent to those of a regular army, the involvement of a state seemed to add a potentially superfluous element. International law does provide for responses to a use of force falling short of an armed attack - Security Council action or countermeasures and reprisals (sanctions). However, the Security Council can be notoriously ineffective and, as the Court noted in Nicaragua, countermeasures are only legal if they are non-forcible:7

Nonetheless, while inter-state self-defence may leave a gap that may be frustrating for the strategic interests of states, the scope of this gap also contains notable ambiguities. For example, at what point does support, scale or effect become substantial enough to constitute an armed attack?" This gap has been filled with various claims of self-defence which seem to deviate from this inter-state model.


While the International Court in Nicaragua upheld the interstate model of self-defence, there is little doubt that when states have sought, for various reasons, to extend the law of armed conflict to situations involving the non-state actors, they have used the right of self-defence to do so.

Judge Schwebel, Dissenting Opinion, ICJ Reports (1986) p. 350, para. 177.
is Judge Jennings, Dissenting Opinion, ICJ Reports (1986) pp. 543-4.
16 Reisman loc. cit. no. 3 at p. 196.
17 ICJ Reports (1986) p. 127, para. 249.

See Yoram Dinstein, War, Aggression and Self-Defence (Grotius Publications, Cambridge, 1988) at p. 182; Antonio Cassese, "The International Community's 'Legal' Response to Terrorism" 38 ICLQ (1989) pp. 589-608 at p. 599; Oscar Schachter, "Self-Defense and the Rule of Law" 83 AJIL (1989) pp. 259-277 at p. 267.
2005 The Right of Self-Defence: Against Whom? 39


One of the first important attempts to extend self-defence to non-state actors took place in the late 1960s and 1970s and this was to extend the concept to "peoples" and national liberation movements. The focus of this right were the struggles against the last vestiges of colonialism then being carried out in southern Africa against a recalcitrant Portugal and the racist regimes of Southern Rhodesia and South Africa. Many African, Asian and Socialist states supporting those movements argued that colonial or racist regimes constituted an inherent aggression against a "people", which correspondingly entailed a right of self-defence.

This was somewhat at odds with the wording of article 51, which specifically referred to states as the subjects of the right of self-defence. Nonetheless, this argument was frequently made in the drafting of some of the key instruments on the use of force in this period, in particular, the Friendly Relations Declaration, GA Res. 2625(XXV) of 1970 and the General Assembly's Definition of Aggression.19

19 India, A/AC.125/SR.64 (1967) p. 5; Algeria, A/AC.125/SR.64 (1967) pp. 6-7; Poland, A/AC.125/SR.64 (1967) p. 8; Ghana, A/AC.125/SR.64 (1967) pp. 13-4; Syria, AJAC.125/SR.65 (1967) pp. 1 1 -2; Yugoslavia, A/AC.125/SR.65 (1967) p. 14; Kenya, A/AC:125/SR.65 (1967) p. 18; Romania, A/AC.125/SR.66 (1967) p. 9; Madagascar, A/AC.125/SR.70 (1967) p. 11; Cameroon, A/AC.125/SR.70 (1967) p. 14; USSR, A/AC.125/SR.89 (1968) p. 93; Czechoslovakia, 21 GAOR (1966) 6th Cmttee., 924th mtg., (A/C.6/SR.924) para. 25; Ukrainian SSR, ibid. 928th mtg., (A/C.6/SR.928) para. 15; Romania, ibid. 934th mtg., (A/C.6/SR.934) para. 12; Libya, ibid. 935th mtg., (A/C.6/SR.935) para. 20; Mongolia, ibid. para. 25; Indonesia, ibid. para. 32; Cuba, 22 GAOR (1967) 6th Cmttee., 995th mtg., (A/C.6/SR.995) para. 9; Congo (Brazzaville), ibid. 998th mtg., (AIC.6/SR.998) para. 6; Hungary, ibid. 999th mtg., (A/C.6/SR.999) para. 8; Tanzania, ibid. para. 65; Senegal, ibid. 1002'1 mtg., (A/C.6/SR.1002) para. 34; Somalia, ibid. 1003rd mtg., (A/C.6/SR.1003) para. 47; Tunisia, ibid. 1004th mtg., (A/C.6/SR.1004) para. 17; Iraq, 23 GAOR (1968) 6th Cmttee., 1095th mtg., (A/C.6/SR.1095) para. 25; Zambia, ibid. 1096th mtg., (A/C.6/SR.1096) para. 22; Algeria, ibid. para. 29; Cyprus, ibid. para. 41; Kuwait, 24 GAOR (1969) 6th Cmttee., 1162hd mtg.,
40 Yearbook of New Zealand Jurisprudence Vol 8.1

It was also claimed that in exercising this right peoples could receive assistance from states, and this did not violate of the UN Charter. However, this interpretation of self-defence was also heavily criticised, especially by Western countries, who argued that article 51 only applied to states21 and that expanding the concept undermined the UN Charter and international peace and security.22

This concept of self-defence did actually make an impression on these instruments, albeit a rather ambiguous and controversial one. Both the Friendly Relations Declaration and the Definition of Aggression dealt with the matter a delicately worded balance which papered over strong differences between states rather than resolve them. Principle 5, paragraph 5, of the Friendly Relations Declaration referred to a general duty of states to refrain from forcible action, which deprived peoples of their right to self-determination and freedom and independence. Peoples who had been forcibly deprived of such a right were entitled to take action against and resist such forcible action. This did suggest some right of self-defence, although in a much weaker form than proposals by African, Asian and Socialist countries.23 What

(A/C.6/SR.1162) para. 4; Mexico, ibid. para. 57; Sudan, ibid. para. 64; Bulgaria, ibid. para. 87; Pakistan, 25 GAOR (1970) 6th Cmttee., 1179th mtg., (A/C.6/SR.1179) para. 19.

  1. Senegal, 22 GAOR (1967) 6th Cmttee., 1002" mtg., (A/C.6/SR.1002)
    para. 34; Mexico, 24 GAOR (1969) 6th Cmttee., 1162" mtg., (A/C.6/SR.1162) para. 57; Indonesia, 21 GAOR (1966) 6th Cmttee., 935th mtg., (A/C.6/SR.935) para. 30; Iraq, ibid. 938th mtg., (A/C.6/SR.938) para. 35; Afghanistan, 24 GAOR (1969) 6th Cmttee., 116151 mtg., (A/C.6/SR.1161) para. 22; Mongolia, 25 GAOR (1970) 6th Cmttee., 1182" mtg., (A/C.6/SR.1182) para. 16.


France, AJAC.125/SR.69 (1967) p. 15; Argentina, A/AC.125/SR.70 (1967) pp. 16-7; Australia, A/AC.125/SR.107 (1969) p. 76.

22 UK, A/AC.125/SR.65 (1967) p. 7; Canada, A/AC.125/SR.66 (1967) p. 17; US, A/AC.125/SR.68 (1967) p. 5; Japan, A/AC.125/SR.69 (1967) p. 17; Italy, A/AC.125/SR.89 (1968) p. 83; Netherlands, A/AC.125/SR.107 (1969) p. 86; Sweden, 21 GAOR (1966) 6th Cmttee., 93 3 rd mtg., (A/C.6/SR.933) para. 21.

23 13 Power (Algeria, Burma, Cameroon, Dahomey, Ghana, India, Kenya, Lebanon, Madagascar, Nigeria, Syria, UAR, Yugoslavia): "[P]eoples who are deprived of their legitimate right of self
2005 The Right of Self-Defence: Against Whom? 41

this "action" or "resistance" entailed was never elaborated, but the obvious inference was that resistance to forcible action would likewise involve force. Nonetheless the issue was left open. These peoples were also entitled to seek and receive support in accordance with the "purposes and principles of the Charter". However, again what this entailed was sharply debated between states, some arguing that it was restricted to humanitarian or other non-military assistance, 24 and others that it could perhaps encompass forcible action.25 The Definition of Aggression similarly referred to peoples who had been "forcibly deprived" of the right of self

determination and complete freedom are entitled to exercise their inherent right of self-defence, by virtue of which they may receive assistance from other States." (A/AC.125/L.31 and Add.l-3) 24 GAOR (1969) Supplement No. 19, (A17619) para. 139; 10 Power (Algeria, Cameroon, Ghana, India, Kenya, Madagascar, Nigeria, Syria, UAR, Yugoslavia), (A/AC.125/L.48) ibid. para. 143; Czechoslovakia: "Peoples have an inalienable right to eliminate colonial domination and to carry on the struggle, by whatever means, for their liberation, independence and free development. Nothing in this Declaration shall be construed as affecting the exercise of that right." (A/AC.125/L.16, part VI) 24 GAOR (1969) Supplement No. 19, (A17619) para. 138; Czechoslovakia, Poland, Romania and USSR: "Peoples who are under colonial domination have the right to carry on the struggle, by whatever means, including armed struggle, for their liberation from colonialism and may receive in their struggle assistance from other States." (A/AC.125/L.74) ibid. para. 145.

  1. US, "The text recognized that, in those cases where the right to self
    determination was being forcible denied, the peoples entitled to that right might seek and receive support which was in accordance with the Charter. In the view of the United States, that language did not enlarge rights contained in the Charter and did not constitute a general licence for an international traffic in arms." A/AC.125/SR.114 (1970) p. 83.

25 Cameroon: "Violation of the principle of self-determination by colonial Powers, in particular by the threat or use of force, was contrary to the Charter of the United Nations and to international law; hence the colonial peoples concerned were entitled to liberate their territory from foreign occupation, and it was the duty of the community of nations to give them every kind of assistance in doing so." A/AC.125/SR.70 (1967) p. 14.

determination and again states interpreted "struggle"26 and "support"27 in markedly different ways.


States have also been willing to use the right of self-defence to protect individuals - their nationals overseas.' In 1976 an Air France airbus was hijacked by Palestinian terrorists who diverted it to Entebbe Airport, near Kampala, Uganda, where they held 268 passengers and crew held hostage, many of whom were Israeli. Israeli forces stormed the plane, without the permission of Uganda, and defending its actions before the Security Council, Israel invoked self-defence and the right to take military action to protect its nationals.'

  1. Canada, 29 GAOR (1974) 6th Cmttee., 1474th mtg., (A/C.6/SR.1474) para. 15; Yugoslavia, 29 GAOR (1974) 6th Cmttee., 1479th mtg., (A/C.6/SR.1479) para. 9; Democratic Yemen, 29 GAOR (1974) 6th Cmttee., 1479th mtg., (A/C.6/SR.1479) para. 27.

27 Ghana, AJAC.134/SR.73 (1970) p. 97; Australia, A/AC.134/SR.95 (1972) pp. 32-3; Indonesia, A/AC.134/SR.106 (1973) p. 24; Bulgaria, A/AC.134/SR.108 (1973) p. 42; US, A/AC.134/SR.113 (1974) p. 29; Afghanistan, 25 GAOR (1970), 6th Cmttee. 1206th mtg., (A/C.6/SR.1206) para. 50; Pakistan, ibid. 1207th mtg., (A/C.6/SR.1207) para. 20; Kenya, 27 GAOR (1972) 6th Cmttee., 1350th mtg., (A/C.6/SR.1350) para. 33; Zambia, ibid., 1351th mtg., (A/C.6/SR.1351) para. 8; GDR, 28 GAOR (1973) 6th Cmttee., 14415t mtg., (A/C.6/SR.1441) para. 17; Cuba, ibid. para. 31; USSR, 29 GAOR (1974) 6th Cmttee., 1472nd mtg., (A/C.6/SR.1472) para. 5; Netherlands, ibid., 1473th mtg., (A/C.6/SR.1473) para. 5; Belgium, ibid., 1476th mtg., (A/C.6/SR.1476) para. 11; UK, ibid. 1477th mtg., (A/C.6/SR.1477) para. 24; Turkey, ibid. para. 27; FRG, ibid. 1478th mtg., (A/C.6/SR.1478) para. 19; Congo, ibid. 1478th mtg. (A/C.6/SR.1478) para. 35; Algeria, ibid. 1479th mtg., (A/C.6/SR.1479) para. 33; Cameroon, ibid. 1483th mtg., (A/C.6/SR.1483) para. 13.

See Thomas M. Franck, Recourse to Force: State Action Against Threats and Armed Attacks (Cambridge University Press, Cambridge, 2002) at p. 96.

  1. Israel, S/PV.1939, paras. 101, 104, 106. See Michael Akehurst, "The Use of Force to Protect Nationals Abroad" 5 International Relations (1977) pp. 3-23 at pp. 19-21; Dinstein op. cit. no. 18 at pp. 213-5; Franck op. cit. no. 28 at pp. 82-6.

In May 1975 the United States cited self-defence in its rescue of an American merchant ship, the SS. Mayaguez and its crew of 40, which had been seized by Cambodian authorities in disputed waters between Cambodia and South Vietnam.' After the American embassy in Tehran was overrun by militants and US personnel were taken hostage in November 1979, the United States attempted an ill-fated rescue mission on 24-5 April 1980 which it justified as self-defence.' This operation took place while the case of the hostages was before the ICJ, and, although the Court expressed regret at unilateral action during proceedings, it did not comment on the legality of the operation.' In April 1993 the United States launched a missile attack on Iraq after Iraqi involvement was uncovered in a plot to assassinate a former head of state, George Bush during a visit to Kuwait. The US argued in the Security Council that an assassination attempt on a former Head of State was a direct attack on the state itself, which entitled a right of self-defence under article 51." This position appeared to have support from several members of the Council.' The United States has also raised self-defence in protection its nationals, in part, to justify armed intervention in Grenada in 198335 and Panama in 1989.36

30 Contemporary Practice of the United States relating to International Law, 69 AJIL (1975) pp. 875-9. See Akehurst loc. cit. no. 29 at p. 9; Dinstein op. cit. no. 18 at pp. 186-7.

31 Case Concerning United States Diplomatic and Consular Staff in Tehran (United States of America v. Iran) (Judgment), ICJ Reports (1980) pp. 17-8, para. 32.
32 Ibid. p. 43, paras. 93-4.

  1. US, S/PV.3245, pp. 3 and 6. See Dino Kritsiotis, "The Legality of the 1993 US Missile Strike on Iraq and the Right of Self-Defence in International Law" 45 ICLQ (1996) pp. 162-177; W. Michael Reisman, "The Raid on Baghdad: Some Reflections on Its Lawfulness and Implcations" 5 EJIL (1994) pp. 120-133; Christine Gray, "After the Ceasefire: Iraq, the Security Council and the Use of Force" 65 BYIL (1994) pp. 135-174 at pp. 169-70;
  2. France, S/PV.3245, p. 13; Hungary, ibid. pp. 19-20; UK, ibid. p. 21; Russia, ibid. p. 22; New Zealand, ibid. p. 23; Spain, ibid. p. 24.
  3. US, S/PV.2491, paras. 55, 65-6. See also Saint Lucia, ibid., para. 14; Barbados, ibid., para. 145.


The right of self-defence has also been raised against terrorists. In 1985 Israel attempted in the Security Council to justify an attack on the Palestine Liberation Organisation in Tunisia as a response to "armed attacks" by terrorists.' While the US was sympathetic to the Israeli argument," other members of the council did not agree and, by 14 votes to 0, with the US abstaining, issued a strongly worded condemnation of the Israeli actions, SC Res. 573 (1985).39

The United States took military action against a state sponsor of terrorism in 1986, when it bombed Tripoli in response to an allegedly Libyan sponsored attack on a Berlin nightclub that left three people dead (two American) and 229 injured (79 American). The US argued that this represented self-defence against terrorist acts. However, most states in the Security Council rejected this claim and a resolution condemning the strikes failed only due to the American, British and French veto."

The US directed military action against a terrorist group in 1998 in response to attacks by the Al-Qaeda organisation. On

36 Letter dated 20 December 1989 from the Permanent Representative of the United States of America to the United Nations addressed to the President of the Security Council, S/21035.

Israel, S/PV.2615, para. 193.

  1. US: "...[W]e recognize and strongly support the principle that a State subjected to continuing terrorist attacks may respond with appropriate force to defend itself against further attacks. This is an aspect of the inherent right of self-defence recognized in the Charter of the United Nations." S/PV.2615, para. 252.

39 SC Res. 573 (1985): "Condemns vigorously the act of armed aggression perpetrated by Israel against Tunisian territory in flagrant violation of the Charter of the United Nations, international law and the norms of conduct".

  1. Contemporary Practice of the United States relating to International Law, 80 AJIL (1986) at p. 632. See also Christine Gray, International Law and the Use of Force (Oxford University Press, Oxford, 2000) at pp. 116-7; Abraham D. Sofaer, "Terrorism and the Law" 64 Foreign Affairs (1986) pp. 901-922 at pp. 921-2; Franck op. cit. no. 28 at p. 90.

7 August Al-Qaeda terrorists orchestrated massive bomb attacks on the American embassies in Dar es Salaam and Nairobi causing the death of over 250 individuals, mostly local Tanzanians and Kenyans, but including twelve American nationals. On 20 August the US responded with cruise missile attacks on installations in Afghanistan and Sudan, states which were alleged to be harbouring the terrorist group. Among the targets were Al-Qaeda training camps in Afghanistan and a chemical weapons plant in the Sudan. In a letter to the Security Council, America argued that these strikes, directed against, "installations used by the Bin Laden organization", were an exercise of the right to self-defence under article 51. Moreover, while Sudan and Afghanistan were targeted, it was not suggested that those states actually exercised control over Al-Qaeda, rather their targeting stemmed from their "cooperation" with it.41

This interpretation of self-defence was vigorously reaffirmed in the wake of Al-Qaeda's attacks on 11 September 2001. These attacks involved suicide terrorists hijacking four American planes and then flying them, respectively, into New York's Twin Towers and the Pentagon, while the fourth crashed en route to the White House, leaving approximately three thousand people dead." The next day the Security Council passed SC Res. 1368 (2001), which specifically recognised, "the inherent right of individual and collective self-defence in accordance with the Charter,' a provision which would, of course, have been out of place if self

41 Letter dated 20 August 1998 from the Permanent Representative of the United States of America to the United Nations addressed to the President of the Security Council, S/1998/780. See also Contemporary Practice of the United States relating to International Law, 93 AJIL (1999) at pp. 162-3. See Ruth Wedgewood, "Responding to Terrorism: The Strikes Against Bin Laden" 24 Yale Journal of International Law (1999) pp. 599-576; Jules Lobel, "The Use of Force to Respond to Terrorist Attacks: The Bombing of Sudan and Afghanistan" 24 Yale Journal of International Law (1999) pp. 537-557;

Contemporary Practice of the United States relating to International Law, 96 AJIL (2002) at pp. 237-9

SC Res. 1368 (2001).
46 Yearbook of New Zealand Jurisprudence Vol 8.1

defence under article 51 did not encompass terrorist attacks. This stance was reaffirmed two weeks later in SC Res. 1373 (2001) on 28 September.' In discussion on SC Res. 1368 (2001) the US representative reiterated comments by President George W. Bush the previous day45 that: "We will make no distinction between the terrorists who committed these acts and those who harbour them.' This interpretation of a right of self-defence in response to a terrorist attack was also supported by members of NATO, who invoked article 5 of the Washington Treaty that an attack had taken place on one of their members,' and by parties to the Inter-American Treaty of Reciprocal Assistance 1947 according to article 3(1) of that treaty."

This right of self-defence was further elaborated by the US Ambassador to the United Nations, John Negroponte in a letter to the UN Security Council on 7 October 2001:

"In accordance with Article 51 of the Charter of the United Nations, I wish, on behalf of my Government to report that the United States of America, together with other States, has initiated actions in the exercise of its inherent right of individual and collective self-defence following the armed attacks that were carried out against the United States on 11 September 2001... Since 11 September, my Government has obtained clear


SC Res. 1373 (2001). See Thomas M. Franck, "Terrorism and the

Right of Self-Defense" 95 AJIL (2001) pp. 839-843.

45 See Steven R. Ratner, "Jus Ad Bellum and Jus In Bello after September 11" 96 AJIL (2002) pp. 905-21 at p. 906.
46 US, S/PV.4370, pp. 7-8.

  1. See Statement by the North Atlantic Council, 12 September 2001, (visited 15/03/05). See also (visited 15/03/05).


RC.24/RES. 1/01, (visited 15/03/05). Article 3(1): "The High Contracting Parties agree that an armed attack by any State against an American State shall be considered as an attack against all American States and, consequently, each one of the said Contracting Parties undertakes to assist in meeting the attack in the exercise of the inherent right of individual and collective self-defense recognized by Article 51 of the Charter of the United Nations." 21 UNTS (1948) pp. 92-105 at p. 95.
2005 The Right of Self-Defence: Against Whom? 47

and compelling information that the Al-Qaeda organization, which is supported by the Taliban regime in Afghanistan, had a central role in the attacks."49

This was, then, primarily a right of self-defence aimed against a terrorist organisation. On the relationship between Al-Qaeda and the Taliban regime in Afghanistan, the Ambassador continued:

"The attacks on 11 September 2001 and the ongoing threat to the United States and its nationals posed by the Al-Qaeda organization have been made possible by the decision of the Taliban regime to allow parts of Afghanistan that it controls to be used by this organization as a base of operation. Despite every effort by the United States and the international community, the Taliban regime has refused to change its policy. From the territory of Afghanistan, the Al-Qaeda organization continues to train and support agents of terror who attack innocent people throughout the world and target United States nationals and interests in the United States and abroad."

There was no suggestion that the Taliban regime actually controlled Al-Qaeda, but merely that it allowed the organisation to operate from its territory. Again, Afghanistan became a target because of its support for rather than control of a terrorist organisation. This interpretation of a right of self-defence encompassing attacks by both states and organisations was spelled out in a reservation by the United States that: "We may find that out self-defence requires further actions with respect to other organizations and other States."'

49 Letter dated 7 October 2001 from the Permanent Representative of the United States of America to the United Nations addressed to the President of the Security Council, S/2001/946.
50 Ibid.

51 Ibid. See also Michael Byers, "Terrorism, The Use of Force and International Law after 11 September" 51 ICLQ (2002) pp. 401-414 at pp. 406-9.


This new practice on self-defence was put to the test by the ICJ in the Wall Opinion of 2004. At issue was a barrier, variously called "security fence" or a "separation wall", which Israel had been constructing on occupied Palestinian territory across the West Bank and East Jerusalem. Palestinians argued that the barrier was an attempt to partition and annex Palestinian territory. However, Israel argued that the barrier, as a measure to prevent terrorist attacks, was, "wholly consistent with the right of States to self-defence enshrined in Article 51 of the Charter". In support of this, it specifically cited SC Res. 1368 (2001) and 1373 (2001), which recognised, "the right of States to use force in self-defence against terrorist attacks", although it insisted that the barrier was a non-forcible measure.'

The Court, though, rejected this argument. Despite noting SC Res. 1368 and SC Res. 1373 (2001), it still saw the glass as half empty - self-defence under article 51 was limited to an, "armed attack by one State against another State." Terrorism against Israel could not be an "armed attack" because it was not, "imputable to a foreign state"." The Court suggested that in almost twenty years since Nicaragua there had been no fundamental change in the law of armed conflict. Nonetheless, it did respond to the two Security Council resolutions, by distinguishing the situation faced by Israel from that contemplated in the resolutions. SC Res. 1368 and 1373 were concerned with international terrorism, whereas the attacks against Israel were from Israeli controlled occupied Palestinian territory and thus internal rather than international in nature.'


Israel, A/ES-10/PV.21, p. 6.

Legal Consequences of the Construction of a Wall in Occupied Palestinian Territory (Advisory Opinion), (2004), (visited 15/03/05), para. 139.

Ibid., para. 139.
2005 The Right of Self-Defence: Against Whom? 49

This limitation of self-defence to just between states was criticised by several judges. Judge Higgins pointed out that article 51 did not specify that an attack had to be by a state, but rather that this had been added by the Court in Nicaragua." Judge Kooijmans considered that the Court had, "regrettably by-passed", what was, "a new approach to the concept of self-defence", whose legal implications could not yet be assessed," while Judge Buergenthal called the approach "formalistic".57


The concept of self-defence in international law shows both strategic and legal dilemmas. States do have a strategic interest in the general prohibition of the threat or use of force between states and this is best served with a clear prohibition in article 2(4) with a clearly limited exception in article 51. Such clarity would, of course, be undermined by attempts to widen self-defence, and, in particular to extend it to difficult and controversial concepts like "terrorists". However, this limited, state to state interpretation of self-defence also inherently leaves a notable gap in the law of armed force, excluding actors who may be engaged in the use of force and setting a high threshold for an armed attack.

It is unlikely that such gaps would remain unfilled. This interpretation of self-defence ignores key developments in modern warfare, in particular, the growth of unconventional conflict and the shifting strategic interests of states. It also suffers from the weakness that article 51 does not specifically spell out this state to state interpretation. Instead the matter is left to custom, which is open to different interpretations. It may be argued that SC Res. 1368 and 1373 (2001) reflect a view, that in regard to changing practice on self-defence, the glass may be half full, while the Wall Opinion saw it as half empty. It is, in fact, quite rare for the Security Council to

55 Judge Higgins, Separate Opinion, ibid., para. 33.
'6 Judge Kooijmans, Separate Opinion, ibid., para. 35.
57 Judge Buergenthal, Declaration, ibid., para. 6.

issue resolutions specifically condemning wider interpretations of self-defence. Of course, in large part, this may be because many of these purported acts of self-defence are by veto-wielding PS states, but also there usually has been some support from other states in the Council. This degree of acceptance tends to depend on the context.

However, transferring self-defence from between states to concepts like "terrorists" extends the right in an ambiguous and perhaps open-ended way and obviously creates scope for abuse. It has been noted that many of these appeals to self-defence closer resemble the language of armed reprisals.' If this is the case then the gap in self-defence now seems to have been occupied to legalise forcible reprisals — the formally unlawful middle ground between non-forcible countermeasures in response to a breach of international law and the use force in response to an armed attack. This would be a significant erosion of article 2(4).

These tensions, however, seem inherent in the right of self-defence. International law creates a medium through which various strategic interests are negotiated and self-defence remains one of the most popular mechanisms for doing so. This is because, firstly, it is a recognised exception to the general prohibition on the threat or use of force in the UN Charter, and, secondly, because it contains notable points of ambiguity which can be filled with various interpretations. While there may be preferred understandings of article 51, it seems likely that different versions of self-defence will continue to emerge in response to developing strategic challenges.

58 Rosalyn Higgins, Problems and Process: International Law and How

We Use It (Clarendon Press, Oxford, 1994) at p. 245; Albrecht Randelzhofer, "Article 51" in Bruno Simma ed., The Charter of the United Nations: A Commentary (Oxford University Press, Oxford, 2002) vol. 1, pp. 788-806 at p. 794; Reisman loc. cit. no. 33 at p. 125; Kritsiotis loc. cit. no. 33 at pp. 166, 175;

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