CYIL vol. 8 (2017)

CYIL 8 ȍ2017Ȏ THE USE OF FORCE AGAINST THE ISLAMIC STATE ȍ JUS AD BELLUM ASPECTSȎ time, they are not protected against the use of force by other actors; only the State(s) on the territory of which they operate is(are). This interpretation is occasionally contested by those who claim that non-state actors should be made part of the jus ad bellum regulation. How, to what extent and under what conditions this should be done remains, however, controversial. The prohibition of the use or threat of force is not absolute. The UN Charter explicitly foresees two exceptions to it. The first exception is that of the UN Collective Actions under Chapter VII of the UN Charter. 38 Pursuant to Article 39 of the Charter, the UN Security Council may determine that a certain situation amounts to a “threat to the peace, breach of the peace, or act of aggression”. Pursuant to Article 42, the Council may – if the collective measures not involving the use of armed force provided for in Article 41 turn out to be or seem inadequate – “take such action by air, sea, or land forces as may be necessary to maintain or restore international peace and security”. The UN Charter foresees that such actions should be undertaken by armed forces made available by UN member States by means of special agreements concluded with the UN. Since, however, no such agreement has ever been concluded, the model of UN-led operations provided for in the Charter has been replaced by the model of UN-authorized operations. Such operations are authorized by the UN Security Council but carried out by States, coalitions of States or regional organizations which keep the operative leadership. The authorization has to be explicit and granted ex ante (i.e. before the operation). The second exception foreseen by the UN Charter is self-defence. 39 Article 51 stipulates that “/n/othing 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”. Self-defence is conditioned on the occurrence of an armed attack: international law fails to give a precise definition of an armed attack but the prevailing view is that only the most serious instances of the use of force amount to an armed attack. Self-defence can be individual, with the attacked State defending itself against the attacker, or collective, in which case the attacked State has to declare itself to be the victim of an armed attack and has to request the help of other States. 40 The use of force in self-defence, both individual and collective, has to meet the criteria of necessity and proportionality set in customary rules, and has to stop as soon as the armed attack is thwarted and/or the UN Security Council takes necessary and adequate measures (typically under Article 42 of the UN Charter). 41 In addition to the UN collective actions and self-defence, intervention by invitation, albeit not featuring in the UN Charter, is generally accepted as a lawful instance of the use of force on the territory of another State. 42 Intervention by invitation is a military intervention undertaken at the invitation, and with the consent, of the government of the territorial State. In the Democratic Republic Congo v. Uganda Case (2005), the ICJ accepted the legality of 38 See GRAY, Christine, International Law and the Use of Force, 3rd Edition, Oxford University Press, 2008. 39 See KUNZ, Joseph L., Individual and Collective Self-Defense in Article 51 of the Charter of the United Nations, American Journal of International Law , Vol. 41, No. 4, 1947, pp. 872-879. 40 ICJ, Nicaragua Case, op. cit., par. 199. 41 ICJ, Nicaragua Case, op. cit., par. 227-238. 42 See NOLTE, George, Intervention by Invitation, in WOLFRUM, Rüdiger (ed.), Max Planck Encyclopedia of Public International Law, MPI Heidelberg/Oxford University Press, Vol. VI, 2012, pp. 282-288.

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