CYIL 7 ȍ2016Ȏ PRINCIPLES OF THE CHARTER OF THE UNITED NATIONS ȃ JUS COGENS ? UN and its Charter, we must ask a question regarding the free will of States in the case of potential amendments to the Charter, particularly its fundamental principles determined in Articles 1 and 2 of the Charter. Irrespective of its quasi-constitutional features, the Charter is formally a multilateral treaty. It has been concluded by States and may thus also be modified by them, in accordance with a complex procedure determined by the Charter itself. Although we can claim that today the principles of the Charter, in particular, are considered to be customary international law, this does not entail that UN Member States could not modify it, including its Articles 1 and 2, by a necessary majority (simply put, two thirds of Member States, including the five permanent members), and, for example, abrogate or limit it or even adopt an amendment permitting the use of armed force. It is hypothetically possible for such an amendment to Paragraph 4 of Article 2 of the Charter to derogate (e.g. in relation to the fight against international terrorism) from the prohibition of the threat or use of armed force, as contained in Paragraph 4 of Article 2 of the Charter. Considering today’s general social awareness of the unacceptability and unlawfulness of war, considering the genesis of such prohibition in the Charter, 5 via the League of Nations, the Kellogg-Briand Pact, numerous declarations and resolution adopted within the UN itself, other international instruments, case law of the ICJ and other international courts and tribunals, national courts and practice of the States based on this provision of the Charter, and considering the practically unanimous opinion of the legal theory, it would be absurd – although formally possible – to abrogate or amend this provision of the Charter in such a manner that the prohibition contained therein would be hollowed out. If this principle of the Charter (its Paragraph 4 of Article 2) is jus cogens – and the same would logically apply to other principles of the Charter – States are not allowed to derogate from or hollow out this fundamental principle – i.e. the prohibition of the threat or use of armed force – by concluding a new treaty. Treaties that are contrary to jus cogens are void, as determined by Article 53 of the VCLT! The principles of the Charter are thus “untouchable” in the sense of Article 53 of the VCLT if they are jus cogens . Jus cogens in international law We will return to the issue of fundamental principles of the Charter and their jus cogens nature later, since this is the central question of the present debate. But before that, we need to answer a few questions related to the concept of jus cogens du concept de jus cogens , in: 113 (4) Revue Générale de Droit International Public 837 (2009); by the same author, Theorie du jus cogens international , Paris 2001; A. HAMEED, Unravelling the Mystery of Jus Cogens in International Law, in: B. Y. I. L, 2014, vol. 84, no. 1, pp. 52-102. 5 On the genesis of this prohibition in the Charter of the UN see for example: A. A. C. TRINDADE, The Primacy of International Law over Force, in: Promoting Justice, Human Rights and Conflict Resolution through International Law , ed. M. Kohen, Leiden 2007.