State responsibility and self-defence in international law post 9/11: has the scope of article 51 of the United Nations Charter been widened as a result of the US response to 9/11?

• Author: Cenic, Sonja

In the aftermath of 9/11, there has been a general consensus that an armed attack of sufficient gravity is still a requisite element to establish the right of self-defence in international law. Debate has however surrounded the level of state responsibility required to invoke this right. It has been suggested that a new threshold has arisen post 9/11 and that state responsibility now encompasses the 'harbouring' of non-state actors. The author examines this argument in light of the international community's support for the US response to 9/11, the two Security Council Resolutions affirming the right and State practice post 9/11. The author then proposes a suitable threshold of state responsibility appropriate for today's threats.

Introduction

Six years following the terrorist attacks of September 11 2001 the images of that day still resonate in the international community, while the United States' response in apparent self-defence against the attacks has fuelled the current debate about the scope of the right of self-defence in international law. The prohibition on the use of force in international law is paramount to the preservation on the use of force in international law is paramount to the preservation of international peace and security. article 51 of the United Nations Charter ('UN Charter') gives States a right to defend themselves against an armed attack, and is one of only two exceptions to the prohibition on the use of force in article 2(4). (1) Not many States have in the past resorted to article 51 to justify responses to terrorist attacks. (2) Traditionally, in order for a State to resort to armed force in self-defence, it needs to demonstrate that it has suffered an armed attack to sufficient gravity, and for which another State is responsible. (3) In terms of a terrorist attack, the settled law at present states that the level of State responsibility verges on that State having an active role in supporting the terrorist group responsible, that is, the State against which force will be used needs to have been an active participant. (4)

This view however has recently been challenged. Following the September 11 2001 terrorist attacks in New York and Washington (hereafter 9/11), the United States, claiming to be exercising its right to self-defence, (5) launched 'Operation Enduring Freedom' (6) in Afghanistan, declaring that the 9/11 attacks were made possible 'by the decision of the Taliban regime to allow parts of Afghanistan that it controls to be used by Al-Qaeda as a base of operation'. (7) This claim alluded to passive, rather than active support by the Taliban, and such justifications for the use of force in self-defence were in the past met with condemnation from the international community. (8) The US justification was however seemingly met with approval by the international community, with the Security Council passing Resolutions 1368 and 1373 condemning the 9/11 attacks and reaffirming the right of self-defence.

As a result of the two Security Council resolutions and the overwhelming support of the international community, it has been suggested that the scope of self-defence under article 51 has become wider with respect to the level of state responsibility required to attribute the acts of terrorists to a State which supports them. (9) Many arc now suggesting that active participation by a State is no longer the required standard, and that States which 'harbour' terrorists make themselves subject to the use of force in self-defence by the victim State. (10)

When one considers that the prohibition on the use of force in the UN Charter has at its core the protection of the international community against die ravages of war through the preservation of international peace and security, any arguments as to the widening of the scope of the right of self-defence should be carefully examined. Part one of this paper provides a brief overview of the right of self-defence under the UN Charter. The scope of the right of self-defence is examined pre and post 9/11, in parts two and three respectively. Whether there has been a change in the law of self-defence is addressed in Part four, while Part five looks at the need to distinguish between varying levels of State support. The author argues that, despite the support of the international community for the US response to 9/11, it is unlikely that the scope of self-defence has been widened to encapsulate state responsibility in the form of harbouring non-state actors. The author further argues that there is a need to set a new thershold of state responsibility, one that is wider than the threshold set down in Nicaragua v The United States ('Nicaragua') (11) but narrower than harbouring.

1. Self-Defence in International Law: The United Nations Charter Framework

   Among the purposes of the 1945 UN Charter is that the preservation of international peace and security is paramount. This is achieved through article 2(4), which states:

   All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any other manner inconsistent with the Purposes of the United Nations. Article 2(4) of the UN Charter prohibits the use of armed force, whether it amounts to war or not, and represents an absolute prohibition on the use of force but for a number of exceptions within the UN Charter. One of the exceptions is article 51, which in part states that:

   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. 2. Article 51 and Self-Defence Pre-9/11

   In 1950 Kelsen argued that article 51 only applies in the case of an armed attack and noted that 'the right of self-defence must not be exercised in case of any other violation of the legally protected interests of a Member (of the UN)'. (12) In 1958 Brownlie suggested that the concept of 'armed attack' in article 51 probably refers to 'some grave breach of the peace, or invasion by a large organised force acting on the orders of a government.' (13) He supplemented this view in 1963, noting that that the limits imposed on article 51 would be meaningless if a wider right to self-defence was applicable under the UN Charter. (14)

   1. Nicaragua v United States: the Concept of Armed Attack

      The International Court of Justice ('ICJ'), in 1986, in the case of Nicaragua v The United States, endorsed a narrow view of article 51. (15) The ICJ held that a State's right to self-defence under article 51 is subject to that State having suffered an actual armed attack, (16) and in 2003, in the Oil Platforms Case, confirmed that an armed attack is still the prerequisite element for the use of force in self-defence. (17)

      The ICJ in Nicaragua stated that in order for a State to resort to armed force in self-defence, it needs to demonstrate that it has suffered an armed attack of sufficient gravity, and for which another State is responsible. (18) Thus, an armed attack which invites the application of the right of self-defence was considered by the Court as constituting two elements, sufficient gravity and state responsibility, both of which have to be satisfied before a victim State can use force under article 51.

      (i) Sufficient Gravity

      The ICJ noted that the element of sufficient gravity is necessary in order to distinguish between the gravest forms of the use of force, which amount to an armed attack, from other less grave forms. (19) This element however is not a controversial concept in international law and its applicability in current international law was accepted by the ICJ in the Oil Platforms Case, where the Court applied the sufficient gravity test set down in Nicaragua to hold that attacks by Iran on US ships were not of sufficient gravity to constitute an armed attack and justify the use of force by the US against Iranian oil platforms. (20) The ICJ's confirmation of the sufficient gravity test adopted in Nicaragua is quite significant as it maintains the high threshold at which a State' right of self-defence is triggered. (21)

      (ii) State Responsibility

      The Annex to General Assembly Resolution 3314 entitled Definition of Aggression lists the acts which constitute an armed attack when carried out by a State's armed forces. article 3(g) of the Annex however reiterates that such acts, even if not carried out by a State's armed forces, will be regarded as an armed attack if supported by the State. the ICJ in Nicaragua affirmed article 3(g) of the Annex and concluded that an armed attack must be understood as including 'not merely actions by regular armed forces across an international border, but also 'the sending by or on behalf of a State of armed bands, groups, irregulars or mercenaries, which carry out acts of armed force against another State of such gravity as to amount to' (inter alia) an actual armed attack conducted by regular forces, 'or its substantial involvement therein'. (22)

      The question in Nicaragua was whether the US, because of its financing, organising, training, equipping and planning of the operations of organised Nicaraguan rebels in Nicaragua, was responsible for violations of international humanitarian law committed by those rebels. The ICJ held that such support did not meet the threshold of state responsibility and that the US did not commit an armed attack. (23)

      The ICJ in Nicaragua developed the 'effective control' test under which to assess whether actions of non-state actors could be attributed to a State. (24) The Court stated that in order to attribute the acts of the rebels co the US it would have to be proved that the US had 'effective control' of the rebels. (25) This, and the references to 'sending by or on behalf,' suggests that pre-9/11 there was a requirement of direct state...