The Right to Self-Defence

The third and final relevant exception to the general prohibition on the use of force by a state is the right to resort to force in lawful self-defence. The classic definition of the right of a state to act in self-defence in customary international law comes from The Caroline Case.29 It is not proposed to detail at length the facts of this case, which are well-recited in the extant literature on self-defence under the jus ad bellum. In correspondence with the British Government following the incident involving The Caroline, the US Secretary of State, Daniel Webster, set out what he considered to be the elements of self-defence in international law. There had to exist, Webster posited, “a necessity of self-defence, instant, overwhelming, leaving no choice of means, and no moment for deliberation.” Such elements had to exist before self-defence could

27

Article 42 of the UN Charter. 28

See UNSC Res.1973 (17/03/11). 29

29 BFSP, p.1137, and 30 BFSP, p.195. See also R.Y. Jennings, ‘The Caroline and McLeod Cases’, 32 AJIL, 1938, at 82.

become a legitimate justification for resorting to force, which could neither be unreasonable nor excessive, “since the act, justified by the necessity of self-defence, must be limited by that necessity, and kept clearly within it.”30 The British accepted these basic elements of the right to self-defence in 1837, and they now form part of customary international law.

The inherent right of a state to resort to force in self-defence was further expressed in Article 51 of the UN Charter, which provides:

Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security. Measures taken by Members in the exercise of this right of self-defence shall be immediately reported to the Security Council and shall not in any way affect the authority and responsibility of the Security Council under the present Charter to take at any time such action as it deems necessary in order to maintain and restore international peace and security.

The customary law right of self-defence exists in parallel to, and alongside, Article 51 of the UN Charter, and has not been superseded by it. This co-existence is clearly rooted in the very nature of sovereignty. The State, as the supreme authority under international law, must be empowered by international law to respond to threats against its nationals and its territorial integrity. As Newton rightly submits, it is, “modern consensus that the sovereign right of self-defence did not originate in Article 51 of the United Nations Charter and is not restricted to responses enumerated

therein.”31

That there exists such a right of self-defence under the jus ad bellum is without doubt, however the scope of such a right has been the subject of much controversy and

30

Ibid.

31

See Michael Newton, ‘Flying into the Future: Drone Warfare and the Changing Face of

Humanitarian Law’, 39 Denver J. Int’l Law & Pol’y (2011) 601, at 604. Indeed, in the Nicaragua case, the ICJ clearly established that the right of self-defence existed as an inherent right under customary international law as well as under Article 51 of the UN Charter. See Military and Paramilitary Activities In and Against Nicaragua (Nicaragua -v- USA) (Merits) [1986] ICJ Rep. 14, pp.14, 94.

extensive debate amongst commentators, in particular with regard to the use of force in countering terrorism.32

Most, but not all, scholars agree that, for a state to make a legitimate claim that it is entitled to resort to the use of force further to its inherent right to self-defence, it must demonstrate that it has been subjected to an armed attack. In this respect, the onus of proof rests on the victim state. The ICJ stated clearly in Armed Activities on the Territory of the Congo (Democratic Republic of the Congo -v- Uganda) (Judgement) that:

Article 51 of the Charter may justify a use of force in self-defence only within the strict confines there laid down. It does not allow the use of force by a state to protect perceived security interests beyond these parameters.33

The degree of threat or use of armed violence required to constitute an ‘armed attack’ is an issue that divides commentators. A minority of scholars hold the opinion that a state may respond in self-defence to any threat, even those not rising to the level of an armed attack.34 These scholars argue that a state should not be required to withhold a response of self-defence until the threat escalates to the level of an armed attack.35 To require such would create a gap in the law where a state could not respond to serious threats against its nationals or territorial sovereignty, which would render to right to self-defence entirely meaningless. Schwebel further opines that the language of Article 51 lacks condition. Its articulation that a state has a right to self-defence if an armed attack occurs could be an indication that the framers of the UN Charter did not intend to limit the right to self-defence “if and only if” an armed attack occurs.

However, the majority of scholarship holds the view that a state must be the victim of an armed attack in order to lawfully resort to force in self-defence.

32

See, for example, J. Kammerhofer, ‘Uncertainties of the Law on Self-Defence in the United Nations Charter’, (2004) 35 NYIL 143. See also C.J. Tams, ‘The Use of Force against Terrorists’, (2009) 20 EJIL 359.

33

[2005] ICJ Rep. 168, at para.148. Hereinafter referred to as Armed Activities. 34

See Myres S. McDougal and Florentino P. Feliciano, Law and Minimum World Public Order (1961). See also Stephen M. Schwebel, Aggression, Intervention and Self-Defence in Modern International Law, in Justice in International Law: Selected Writings of Judge Stephen M. Schwebel (1994). 35

Prior to the 9/11 attacks, it was open to question whether an attack perpetrated by a terrorist group could constitute an ‘armed attack’ for the purposes of engaging Article 51 of the UN Charter. Prior to the 9/11 attacks, state practice and the weight of academic opinion weighed against the concept in international law of a right to self- defence against non-state actors. Indeed, few openly supported the existence of such a right in the absence of some element of state complicity in the activities of the non- state actor. As Murphy rightly submits, “prior assertions that terrorist acts constituted an “armed attack” justifying a robust exercise of self-defence have not met

widespread acceptance by the global community.”36 However, this position has changed markedly in consequence of the 9/11 attacks. The day following the attacks, the UN Security Council recognised the United States’ right to self-defence in this instance.37 Further, NATO’s North Atlantic Council stated that the attacks should be viewed as an action covered by the Treaty of Washington, which states that an armed attack against one or more of the members of the alliance shall be considered an attack against them all, if it was determined that the attacks emanated from a foreign state.38 This apparent shift in position, which may be political as much as an

intentional broadening of the scope of the right to self-defence, is recognised by an evolving state practice with regard to countering international terrorism. Gray and Lubell take the view that, from the international response to the 9/11 attacks, there could, under certain circumstances, be a right of self-defence against non-state actors who perpetrate acts of terrorism, even where there is little or no state complicity in those acts.39 The difficulty, however, lies in properly delineating the scope of such a right. Certainly, Article 51 does not expressly specify that an armed attack must be perpetrated by a state, but in the event of an attack by a non-state actor with no state complicity in that attack, the question of what constitutes a permissible response in self-defence becomes more problematic. In part, this difficulty is due to the fact that an ‘attack’ must be of a sufficient intensity to constitute an ‘armed attack’. According to the ICJ in Nicaragua, only the, “most grave forms of the use of force” constitute an

36

See S.D. Murphy, ‘Terrorism and the Concept of “Armed Attack” in Article 51 of the UN Charter’, (2002) 43 Harv. Int’l L.J. 41, at 46.

37

UNSC Res. 1368 (12/09/01). See also UNSC Res. 1373 (28/09/01). 38

North Atlantic Treaty Organisation, Statement by the North Atlantic Council (12/09/01), available at http://www.nato.int/docu/pr/2001/p01-124e.htm, accessed 27 February 2015.

39

See C. Gray, International Law and the Use of Force, (3rd edn, OUP, 2008), at 199-202. See also N. Lubell, Extraterritorial Use of Force Against Non-State Actors, (OUP, 2010), at 31-36.

armed attack.40 The Court also opined that an armed attack must reach a certain significant scale of violence above, “mere frontier incidents.”41 In line with the Nicaragua judgment, O’Connell submits that sporadic rocket fire, or small armed groups crossing a border, would not rise to the level of an armed attack.42 Dinstein, however, argues that smaller scale attacks constitute armed attacks triggering a state’s right to self-defence, provided that the scale and effects are not de minimis.43 In line with this thinking, Judge Jennings opined that it would be dangerous to unnecessarily restrict the right to self-defence, as it would limit a state’s ability to lawfully respond to a threat to its sovereignty.44Certainly, the response of the international community recognising that the 9/11 attacks were of sufficient gravity to trigger the United States’ right to self-defence, offers little by way of assistance in this regard. Although recognising the threat posed by terrorism to international peace and security, the 9/11 attacks are the only specific instance where the UN Security Council has specifically recognised a right of self-defence in response to a specific terrorist attack.

This minimum threshold requirement in Article 51 has been the subject of much dispute, with claims from some states, in particular, Israel, that there exists an ‘accumulation of events’ doctrine, whereby a series of small-scale, sporadic terrorist attacks, designed to achieve an objective that could not be achieved by a single concentrated attack, could be weighted cumulatively in determining whether the threshold requirement has been satisfied. O’Connell submits that the sporadic nature of terrorist acts is precisely the reason why states should be required to respond to acts of terrorism using law enforcement methods within the human rights framework, as opposed to military force.45 A string of terrorist attacks, O’Connell argues, must be evaluated on a case-by-case basis, and cannot accumulate to constitute an armed attack.46 However, there is a contention that the accumulation of attacks is justified when there exists a coordinated campaign of violence. Israel has been a staunch advocate of this doctrine in relation to its operations against Hezbollah militants launching attacks against Israel from Lebanon.47 The ICJ has referred to the doctrine

40

See Nicaragua, supra n.35, at para.191. 41

Ibid, at para.195. 42

See Professor Mary Ellen O’Connell, ‘Remarks: The Resort to Drones under International Law’ 39 Denver J. Int’l Law & Pol’y (2011) 585, at 597.

43

See Y. Dinstein, supra n.19, at 195. 44

See Nicaragua, supra n.35, at 543-544. 45

See O’Connell, supra n.42, at 593. 46

Ibid. 47

in passing, with several judicial remarks seemingly endorsing the doctrine, at least implicitly. In Nicaragua, the ICJ stated:

Very little information is however available to the Court as to the circumstances of these incursions or their possible motivations, which renders it difficult to decide whether they may be treated for legal purposes as amounting, singly or collectively (emphasis added) to an ‘armed attack’ by Nicaragua on either or both states.48

Later, in Islamic Republic of Iran -v- USA (Judgment), the ICJ opined:

…the question is whether that attack, either in itself or in combination with the rest of the “series of…attacks” (emphasis added) cited by the United States can be categorised as an “armed attack” on the United States justifying self-defence.49

Finally, in Armed Activities, the Court stated:

The Court is of the view that, on the evidence before it, even if this series of

deplorable attacks could be regarded as cumulative in character (emphasis added) they still remained non-attributable to the Democratic Republic of the Congo.50

Notwithstanding these passing judicial comments, implicitly endorsing the ‘accumulation of events’ doctrine, until recently the doctrine was controversial. However, in the years following 9/11, it is submitted that legal opinion seems to have shifted to such an extent that the doctrine finds considerable support amongst

commentators, particularly in relation to attacks by irregular armed bands and terrorist groups. Dinstein, for example, submits that if, “continuous pin-prick assaults form a distinctive pattern, a cogent argument can be made for appraising them in their totality as an armed attack.”51 This certainly seems to be reflected in recent state practice, with Tams rightly pointing to an increasing willingness amongst states to accept the doctrine.52

48

See Nicaragua, supra n.35, at para.191. 49

[2003] ICJ Rep. 161, at para. 64. Hereinafter referred to as Oil Platforms. 50

Armed Activities, supra n.33, at para.146. 51

See Y. Dinstein, supra n.19, at 230-231. 52