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Issue of the Right to Self-Defence and Terrorism

Info: 4422 words (18 pages) Law Essay
Published: 27th Nov 2020

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Article 51 of the United Nations Charter contains a State’s right to use Self-Defence in the event of an armed attack targeted at its territory[1]. The right contained under Article 51 is an exception to the strict prohibition on the use of force under Article 2 (4) of the Charter[2], which forms a Jus ad Bellum norm in international law that any use of force is prohibited against another state[3] in the absence of authorisation from the United Nations Security Council. Due to the strict prohibition on the use of force and the restrictive measures contained within Article 51 before a state may act against an armed attack, a right of Anticipatory Self-Defence has emerged within Customary International Law which would presumably allow a state to act on an ‘imminent’ threat[4] to peace, security and territorial integrity. The right to anticipatory self-defence originated from the 1837 Caroline Case which set out a criterion for when a state may act in self-defence prior to the start of an armed attack. State practice of this right was relatively irrelevant and not often relied upon pre 9/11, however the attacks of September 11 2001 has sparked controversial discussion over the legality of such a right in international law due to its sensitive and complex relationship with the restrictions which exist under Article 51 of the Charter. The purpose of the restrictive nature of Article 51 is aligned with the purpose of the UN Charter itself, being to maintain international peace and Security[5]. However, in an age of International Terrorism, many States and scholars have begun to question the sustainability of such a restrictive doctrine, which could lead to mass global devastation if adhered to.

Before addressing any doctrinal forms of self-defence which have emerged since the 1960’s (more predominantly since 9/11), the nature of treaty law must be understood in its plain terms. The provisions of the right to self-defence under Article 51 are a constituent part of the peremptory rule of the prohibition of the use of force by States. The nature of the right contained within the premise of article 51 is exceptional and not simply a situation or circumstance which may exclude wrongful behaviour[6]. The rights contained in Article 51 are generally construed as being interpreted in a restrictive manner, in order to limit any use of force by states, adhering to the prohibition to the use of force where possible. A starting point for such a restrictive understanding of Article 51 is Article 31 of the Vienna Convention, which states that when interpreting treaty provisions, ‘any expression is presumed to have its ordinary meaning’[7] and that ‘no special or out-of-the-ordinary meaning can be admitted unless it can be shown that such was the parties intent’[8]. In the Armed Activities case, the International Court of Justice (ICJ) reaffirmed this notion that where a state intends to exercise its right to self-defence under Article 51, it is for that State to prove it in the circumstances present[9]. Scholars which defend the restrictive interpretation of Article 51 by states base this on the basis that only armed attack was included as a basis for self-defence. This is significant due to the nature of article 2(4) which prohibits not only the use of force, but the threat of force also[10]. It is clear when looking at the formation of article 51 that if the threat of the use of force were to be included in the premise of article 51, the right to self-defence could easily be wrongly used as a pretext for unwarranted war[11]. If the provisions of article 51 of the Charter are to be read in line with Article 31 of the Vienna Convention, the only grounds on which a state may initiate a riposte on another State is where an armed attack has occurred[12]. When considering the implications of article 51 being exercised, it does appear to require a restrictive interpretation of its provisions. This is since where the conditions are met and the right is triggered, a state may exercise unilateral force[13], despite whether other member States are in support of the use of force. It is only where the Security Council decides under Article 39 of the Charter that action is needed to maintain peace and security, that the need for collective security may be triggered[14]. Where a state may initiate a riposte to an armed attack unilaterally, there is clearly greater prospect of such actions by both States could result in disproportionate force and lack of communication, essentially forming the basis for war.

The legitimacy and existence of an extended form of self-defence, namely that of anticipatory self-defence has been widely debated by States and scholars alike since the formation of the Charter’s provisions of self-defence.  The existence of anticipatory self-defence is justified by its advocates on the basis that a state cannot wait to suffer the devastating effects of an attack which it knows is imminent but be expected to not defend itself[15]. Shah has described the rejection of a form of anticipatory self-defence as ‘protecting the enemies right to strike first’[16]. Advocates of this form of self-defence depend on the phrase ‘inherent right’[17] of self-defence contained in the provisions of Article 51. The provisions of Article 51 state that nothing in the UN Charter ‘shall impair a state’s right to inherent self-defence’[18], which some have interpreted to be a protection of the customary law of self-defence prior to the formation of the Charter. Pre 1945 custom consisted of a right for a state to respond to an imminent armed attack in self-defence based on the provisions of Caroline[19]. The custom set by Caroline establishes that a state may act in self-defence in anticipation of an imminent attack where the necessity of such ‘instant, overwhelming, and leaving no choice of means, and no moment for deliberation’. The key distinction between anticipatory self-defence and that of pre-emptive self-defence, is the requirement that an attack must be imminent in order to be legitimate under its custom. Lubell describes the requirement of imminence as an essential component to anticipatory action in order to ensure that anticipatory self-defence is not invoked as an illegitimate pretext for war[20]. It is advised therefore that if anticipatory self-defence is to be exercised legitimately, the threat being responded to by a State must be certain to occur and meet the gravity of an actual armed attack in terms of its repercussions[21]. Due to new threats such as international terrorism and complex international politics, the acceptance of anticipatory self-defence has significantly increased. Whilst the ICJ and the United Nations Security Council has, on several occasions, shirred away from providing clarification regarding the legality of ASD, many international bodies have expressed their recognition of such a right. In 2004, the High Panel of Experts examining UN Reform took a decisive stand on the matter, stating that ‘according to long established international law, can take military action as long as the threatened attack is imminent, no other means would deflect it and the action is proportionate’[22]. The stans took by the Panel is strikingly like the provisions of Caroline established in 1837, suggesting that pre-charter custom is still largely prevalent in the current law on self-defence.

Central to the doctrine of anticipatory self-defence is the Israel-Iraq (Nuclear Reactor) Case of 1981. In this case, the Israeli air force launched an air strike on a nuclear research centre near Baghdad, whereby the Israeli government stated that it’s reason for destroying the Iraqi nuclear reactor was due to high purchases of uranium by Iraq. The Israeli government claimed that such production at the centre had the sole purpose of creating atomic weapons which it believed were to be used in an offensive against Israel. The consensus of the UN Member States was profoundly negative towards the Israeli actions due to the lack of evidence provided by Israel that the Reactor was being used for non-peaceful purposes as Iraq so claimed. The adoption of Resolution 36/27, whereby the General Assembly issued a strong warning to Israel about repetition of such an act[23], reflects the absence of any form of evidence that the necessity to respond to any imminent threat was present. Whilst the actions here were strongly condemned by the UN member states, it is clear that there is no denial of a right to act upon an imminent threat for the purpose of self-preservation, but rather that if anticipatory self-defence is to be invoked, the evidence must be substantive and reliable. This reaffirms the idea that any action taken in anticipatory self-defence must be supported by a high threshold of necessity and gravity of threat, and that any such claims must demonstrate such. Franck also reflects on other factors which may contribute to whether action taken in ASD is justified, such as the situational factors of the involved States[24]. He observes the hypocrisy of Israel considering that at the time, Israel was a nuclear power deliberately remaining outside of the regulation and assessment of the Treaty on the Non-Proliferation of Nuclear Weapons, which may be contributory to the negative reaction Israel’s actions generated within the UN[25]. Whilst there is post-Charter evidence that anticipatory self-defence has not been completely disregarded by the international community, cases such as this demonstrates the necessity for a very high standard of evidence of attack (with gravity of an armed attack) in order to prevent unjustified and illegal action which, as shown, may cause the same amount of devastation as the State attempts to prevent[26].

A concern in the wake of a new age of international terrorism is the legal issue of whether the actions of a non-state actor may amount to an armed attack and fall within the criterion for triggering a state’s right to self-defence under Article 51 of the Charter. During negotiations on the UN Definition of Aggression, it was generally accepted by states that the actions of NSA’s would amount to a breach of peace by a host state where their involvement was such that the actions could be attributable to that host state[27]. Although, when finally accepted by the General Assembly by consensus in 1974, aggression did not include that of indirect aggression, Article 3(g) of the UN Definition of Aggression provides that the sending by a state of ‘armed bands, groups or irregular forces’[28] to threaten the territorial integrity or political independence of another state, would in fact amount to aggression[29]. Despite the inclusion of activities of irregular forces within the UN Definition of Aggression, it is still maintained that such aggression must be attributable and originate from the will of another State.

The events pertaining 9/11 in relation to the US’ National Security Strategy are the most valuable examples of state practice in relation to NSA’s and the operation of self-defence under article 51. Most notably, the principles of the Bush doctrine of self-defence encouraged the acceptance of a broader interpretation of Article 51 amongst western states in the face of a new age of terrorism.  The National Security Strategy of 2002 was centred on the idea that the US could no longer rely on reactive posture in relation to its rights of self-defence under Article 51[30], essentially holding that they would no longer specifically rely on the existence of an armed attack before reacting, as Article 51 so requires.  The US waging of war in Afghanistan post 9/11 weakens the idea that self-defence under article 51 may only be exercised inter-states. The armed attacks carried out by Al-Qaeda were not attributable to Afghanistan, however the US-led coalition of self-defence were direct reprisals on the Taliban, rather than just the Al-Qaeda sources of armed attacks. Although the use of US led forces in Afghanistan pertaining 9/11 are the subject of extensive debate, it is clear to see that the state practice in these events make it deducible that self defence against a non-state actor in a non-complicit state may have a place in customary international law and possibly within the framework of the Charter. Whilst being controversial amongst the members of the UN, the US invoked operation enduring freedom as falling into the framework of article 51 successfully evident by Security Council Resolutions 1368[31] and 1373[32].

Central to the issue of whether the actions of a non-state actor can amount to an armed attack under the premises of Article 51 of the UN Charter and further triggering the right of Self-Defence, is the Nicaragua Case. The International Court of Justice’s judgement was of significance in relation to what they considered to constitute an armed attack under the premises of article 51.  Relying on the General Definition of Aggression previously formed by the General Assembly some twelve years earlier, the ICJ stated that the ‘acts of armed bands, groups, irregulars or mercenaries, which carry out acts of armed force against another state of such gravity’[33] as to amount to an actual armed attack carried out by regular forces, or its ‘substantial involvement therein’[34].  The key implication by the court however followed in stating that, to set a more clarified threshold for attribution, the providing of weapons or financial or logical assistance would be insufficient and must extend to the proving of ‘effective control’[35] over irregular forces. The decision of the ICJ in equating the requirement of substantial involvement to the high threshold and difficulty of establishing effective control was controversial not only amongst scholars, but within the court also. Judge Schwebel affirmed that he found the test to be too restrictive given the nature of the threat that international terrorism posed upon States[36], and that the introduction of effective control as a complimentary test to the premises of Article 51 was a departure from the ‘accepted and desirable’[37] customary international law in the area.

Although the ICJ did clarify the extent of involvement needed by from the home state in order to trigger a right to use force (in self-defence) under article 51, the court neglected to address the issue regarding the use of force against terrorist groups within a host state. In response to the war crimes committed in Yugoslavia, the International Criminal Tribunal for the former Yugoslavia lowered the threshold to ‘overall control’ of armed groups[38]. In implying the need for, at least, overall control the court failed to acknowledge the difficulty of such being demonstrated by a State in relation to acts of terrorist groups. In assessing the outcome of both the tests established in Nicaragua and Tadic, Cassese reinforces the difficulty in asserting attribution amounting to a form of control of an armed group, highlighting the ‘close-knit' nature, secretively and dispersion across the globe of such terrorist groups, which would render the tests of control as unreasonable and impossible for states to establish.

Despite the critique attracted by the Nicaragua judgement, the Court continued to entrench its provisions in cases such as the Palestinian Wall case. Within the Wall Advisory Opinion, the Court affirmed its view that it will only recognise a legal use of the right of self-defence where an armed attack occurs inter-state[39], and therefore without Israel asserting the attributability of attacks launched from the West Bank to another state, self-defence would be irrelevant to the proceedings[40]. This clearly demonstrates the courts position in that they will not consider the actions of non-state actors as falling within the premise of Article 51. Although due to the political history of conflicted states such as Israel and Palestine, it may be prima facie obvious where an attack may originate from, however, the court has set the threshold so high in relation to attribution of a state that it is clearly unachievable for states to demonstrate the origin of attacks to another State rather than the armed group in question. In light of the extent and scale of threats posed by terrorist or irregular groups in the twenty first century, in combination with the courts lack of willingness to address the difficult requirements of their current stance on the matter, it would be advisable for states to use a broad interpretation of article 51, however, in situations of the upmost necessity.

Despite the fact that it is undeniable that both the security council and the ICJ have took a very passive approach to the issue of self-defence, the Nuclear Weapons Advisory Opinion in 1996 did provide a degree of clarification as to the relation between Article 51 and the customary international law of self-defence. The Court proceeded in the AO to acknowledge the quality of the dual requirements of necessity and proportionality, stating that the customary international law requirements may be read in accordance with the provisions of article 51 of the UN Charter[41]. Whilst confirming the purpose and practicality of such requirements, the court arguably contributed further to the ambiguity of the position regarding the right of self-defence due to the fact that it was not clarified whether such considerations exist as part of treaty law, or whether they, under customary international law, could be read as complimentary considerations. Such acknowledgement of customary international law by the court has raised, amongst states and scholars alike, whether the two forms of self-defence are as distinctly separate as it may seem. Kreb has stated that the International Court of Justice has rather took the approach of ‘harmonious construction’[42] regarding the law on self-defence, essentially a hybrid between the provisions of article 51 in conjunction with those set out in customary international law. Notably, the only clear distinction which can be made between the two is that when triggering a right to self-defence under article 51, the state using such a right must inform the security council prior to any attack[43].

  However, customary international law provisions regarding self-defence stem from the focus of imminence of such a need for a state to defend itself, and as a result its sole purpose in international law is to circumvent the Charter’s need/requirement to inform the Council. Such a hybrid construction of the right to self-defence under international law has arguably followed through the ICJ’s case history. The Armed Activities case is a pivotal case in establishing the Court’s approach. Although the court has not explicitly stated that it will consider the provisions of treaty law and customary law as one, the court did approach the matter of self-defence in Armed Activities by referring to the matter as ‘the principle of non-use of force in international relations’[44] without citing specifically to its source. Kreb takes this to imply that the use of force by states is ‘essentially based on identical rules of treaty and customary law existing alongside each other’[45]. If we are to take a broad perception of the ICJ’s approach here, to essentially fill in the gaps where they have failed to provide specific clarification, the argument of harmonious construction being referred to here may hold merit. Nevertheless, this approach is a very interpretive view, of the law surrounding article 51, at best.

In conclusion, upon exploring some of the broad interpretations of the provision of Article 51 such as the doctrine of anticipatory self-defence and the relationship between non-state actors and a State’s right to self-defence, it is clear that whilst there is much evidence to suggest that a broad interpretation has embedded itself in both Customary International Law and the jurisprudence of the International Court of Justice, a legal grey area largely exists. In relation to anticipatory self-defence which has been discussed at length, the clear lack of intention to make any form of clarification by both the International Court of Justice and the Security Council suggests that States may in fact approach new threats such as international terrorism with the right to self-defence within the premise of Article 51 of the Charter. For example, the Iraqi-Israeli nuclear reactor case of 1981 demonstrates that the Security Council may deem anticipatory self-defence, under the inherent right feature of Article 51,  legitimate in circumstances where the threat being responded to is imminent and absolutely certain to occur.

Furthermore, the International Law stance in relation to international terrorism, namely non-state actors, remains extremely uncertain.

[1] Article 51, United Nations Charter

[2] Article 2(4), UN Charter

[3] ibid


[5] Article 1, United Nations Charter

[6] Military and Paramilitary Activities (1986) ICJ

[7] Article 31, UN Charter

[8] ibid

[9] Democratic Republic of Congo v Uganda, ICJ Rep. 2005

[10] Article 2(4), UN Charter

[11] Noam Lubell, ‘The Problem of Imminence in an Uncertain World’, in ‘The Oxford Handbook of the Use of Force in International Law’ (First Edition: Published by Oxford University Press: 2015)

[12] Article 51, UN Charter

[13] Article 51, UN Charter

[14] Article 39 UN Charter

[15] Olivier Corten, ‘The Law Against War: The Prohibition on the Use of Force in Contemporary International Law’, (Published by Hart Publishing Ltd: 2010)

[16] Niaz A. Shah, ‘Self-defence, Anticipatory Self-defence and Pre-emption: International Law's Response to Terrorism’, Journal of Conflict and Security Law (Volume 12, Issue 1, Spring: 2007)

[17] Article 51, UN Charter

[18] ibid

[19] Olivier Corten, ‘The Law Against War: The Prohibition on the Use of Force in Contemporary International Law’, (Published by Hart Publishing Ltd: 2010)

[20] Noam Lubell, ‘The Problem of Imminence in an Uncertain World’, in ‘The Oxford Handbook of the Use of Force in International Law’ (First Edition: Published by Oxford University Press: 2015)

[21] ibid

[22] ‘A More Secure World: Our Shared Responsibility, Report of the High-level Panel on Threats, Challenges and Change’, (2004) UN Doc A/59/565

[23] G.A. Res. 36/27 of 13 November 1981

[24] Thomas M. Franck ‘Recourse to Force: State Action against Threats and Armed Attacks’ (Published by Oxford University Press: Online Publication 2009)

[25] ibid

[26] ibid

[27] A/8019 (1970) para 127

[28] UN Definition of Aggression, Art. 3(g)

[29] ibid

[30] The National Security Strategy of the United States of America, September 2002

[31] S.C. Res. 1368

[32] S.C. Res. 1373

[33] ibid

[34] ibid

[35] Case Concerning Military and Paramilitary Activities in and against Nicaragua (Judgment of June 1986) (Merits)

[36] ibid

[37] ibid

[38] Tadic Case (Judgment) ICTY-94-1 (26 January 2000)

[39] Advisory Opinion Concerning Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory (9 July 2004) ICJ

[40] ibid

[41] Legality of the Threat or Use of Nuclear Weapons (1996) ICJ 2

[42] Claus Kreb, ‘The International Court of Justice and The ‘Principle of Non-use of Force’’, in ‘The Oxford Handbook of the Use of Force in International Law’ (First Edition: Published by Oxford University Press: 2015)

[43] ibid

[44] Democratic Republic of Congo v Uganda, ICJ Rep. 2005

[45] Claus Kreb, ‘The International Court of Justice and The ‘Principle of Non-use of Force’’, in ‘The Oxford Handbook of the Use of Force in International Law’ (First Edition: Published by Oxford University Press: 2015)

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