ABSTRACT
Judgment of the court 188 The Court ... finds that both Parties take the view that the principles as to the use of force incorporated in the United Nations Charter correspond, in essentials to those found in customary international law ... The Court has however to be satisfied that there exists in customary international law an opinio juris ... This opinio juris may, though with all due caution, be deduced from, inter alia, the attitude of the Parties and the attitude of states towards certain General Assembly resolutions, and particularly Resolution 2625 (XXV).5 The effect of consent to the text of such resolutions ... may be understood as an acceptance of the validity of the rule or set of rules declared by the resolution by themselves. The principles of non-use of force, for example, may thus be regarded as a principle of customary international law, not as such conditioned by provisions relating to collective security, or to the facilities or armed contingent to be provided under Article 43 of the Charter ... 190 A further confirmation of the validity as customary international law of the principle of the prohibition of the use of force expressed in Article 2, para 4, of the Charter of the United Nations may be found in the fact that it is frequently referred to in statements by state representatives as being not only a principle of customary international law but also a fundamental or cardinal principle of such law. The International law Commission, in the course of its work on the codification or the law of treaties, expressed the view that ‘the law of the Charter concerning the prohibition of the use of force in itself constitutes a conspicuous example of a rule in international law having the character of jus cogens’.6
