CYIL vol. 8 (2017)

CYIL 8 ȍ2017Ȏ THE USE OF FORCE AGAINST THE ISLAMIC STATE ȍ JUS AD BELLUM ASPECTSȎ consent. The aim of such strikes is to end the constant threat to Iraq, protect Iraq’s citizens and, ultimately, arm Iraqi forces and enable them to regain control of Iraq’s borders”. 94 Neither of the two letters explicitly invokes the concept of self-defence or Article 51 of the UN Charter. Despite that, they have been interpreted as implying not only the invitation to intervene in the territory of Iraq (section 4 above) but also a request by a State which regards itself as the victim of armed conflict, for collective self-defence. 95 Several States – the US, 96 the UK, 97 Australia, 98 Germany, 99 Denmark, 100 Norway 101 and Belgium 102 – have relied on this interpretation in their letters to the UN. For instance, in its letter dated 25 November 2015, the UK informs the UN that it is “taking measures in support of the collective self-defence of Iraq as part of international efforts led by the United States. These measures are in response to the request by the Government of Iraq for assistance in confronting the attack by the Islamic State in Iraq and the Levant (ISIL) on Iraq”. 103 Others States (the US, Turkey, France) 104 have taken, in their letters to the UN, a more ambiguous position, invoking either only Article 51 of the UN Charter or individual and collective self-defence indistinguishably. 5.2 Self-Defence against the Acts of Non-State Actors – Armed Attack? Self-defence is generally considered lawful under international law. Yet, it is so on the condition that all the criteria listed above (see section 2.2) are met. In case of the use of force in Syria, the main difficulty relates to the fact that the alleged armed attack(s) that was to trigger the right to self-defence came from a non-state actor, the IS. Whereas it is clear that a State has the right to retort by military force to an armed attack waged by another State, it is less clear whether it has the same right in response to attacks carried out by non-state actors, including terrorist groups. It is also debated whether and if so, under what conditions, terrorist attacks may qualify as “armed attacks”. Starting from the latter point: the term armed attack does not have a codified definition under international law. In the Nicaragua Judgment, the ICJ used the so called “scale and effect test”, 105 distinguishing the most grave forms of the use of force that amount to an armed 94 Ibidem. 95 In the 1986 Nicaragua judgment, the ICJ held that “the requirement of a request by the State which is the victim of the alleged attack is additional to the requirement that such a State should have declared itself to have been attacked”. ICJ, Military and Paramilitary Activities, op. cit., par. 199. 96 UN Doc. S/2014/695, op. cit. 97 UN Doc. S/2014/851, Identical letters dated 25 November 2014 from the Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations addressed to the Secretary-General and the President of the Security Council, 26 November 2014. 98 UN Doc. S/2015/693, Letter dated 9 September 2015 from the Permanent Representative of Australia to the United Nations addressed to the President of the Security Council, 9 September 2015. 99 UN Doc. S/2015/946, Letter dated 10 December 2015 from the Chargé d’affaires a.i. of the Permanent Mission of Germany to the United Nations addressed to the President of the Security Council, 10 December 2015. 100 UN Doc. S/2016/34, Letter dated 11 January 2016 from the Permanent Representative of Denmark to the United Nations addressed to the President of the Security Council, 13 January 2016. 101 UN Doc. S/2016/513, Letter dated 3 June 2016 from the Permanent Representative of Norway to the United Nations addressed to the President of the Security Council, 3 June 2016. 102 UN Doc. S/2016/523, Letter dated 7 June 2016 from the Permanent Representative of Belgium to the United Nations addressed to the President of the Security Council, 9 June 2016. 103 UN Doc. S/2014/851, op. cit. 104 See UN Docs S/2014/695, op. cit., S/2015/563, op. cit ., S/2015/745, op. cit. 105 ICJ, Military and Paramilitary Activities, op. cit., par. 195.

251