CYIL Vol. 6, 2015

MANIFEST VIOLATION OF THE UN CHARTER C. Use of force clearly in breach of international law, but not amounting to a manifest violation of UN Charter Because of the qualifier of the crime of aggression – a manifest violation of the UN Charter – there can also be cases that are clearly illegal, but with regard to their character, gravity and scale, they do not amount to a manifest violation of the UN Charter. Therefore, no crime of aggression in such a case can be identified. In other words, not every act of aggression is the basis for criminal responsibility. 7 But it is necessary to realize that even if such a case does not amount to a crime of aggression, it is still illegal. D. Use of force clearly in breach of international law that amounts to a manifest violation of UN Charter The last group concerns the most serious cases of the use of force that do not fall within the grey area. Such situations amount by their character, gravity and scale to a manifest violation of a UN Charter and therefore fulfil the legal requirements for a crime of aggression. 5. ‘Manifest violation’ and Travaux Préparatoires The crucial question is how should we understand the vague term ‘manifest violation’? The Vienna Convention on the Law of Treaties defines the term for the purposes of invalidity of treaties in its Art. 46 para 2 as follows: A violation is manifest if it would be objectively evident to any State conducting itself in the matter in accordance with normal practice and in good faith . In fact, such a definition is still very general and therefore does not help much for our purpose. With regard to interpretation, the Vienna Convention in its Art. 31 lays down these rules: A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose . Art. 32 allows for Travaux Préparatoires to be used as a supplementary means for interpretation. If this were to be used by the Court’s judges in the future, the threshold would be rather high, because the preparatory work reflects the intention to exclude violations the legality of which is subject to genuine legal debate. 8 However, the judges can decide without using the preparatory work. MILANOVIC, Marko. Aggression and Legality: Custom in Kampala. Journal of International Criminal Justice , vol. 10, 2012, p. 183. 7 See CLARK, Roger S. Negotiating Provisions Defining the Crime of Aggression, its Elements and the Conditions for ICC Exercise of Jurisdiction Over It. European Journal of International Law , vol. 20, no. 4, 2009, p. 1105. 8 See HEINSCH, Robert. The Crime of Aggression after Kampala: Success or Burden for the Future? Goettingen Journal of International Law 2 , vol. 2, 2010, pp. 730-731; RUYS, Tom. Defining the Crime of Aggression: the Kampala Consensus. Military Law and Law of War Review, vol. 49, 2010, pp. 97-122. Available also at: https://ghum.kuleuven.be/ggs/publications/ working_papers/new_series/wp51-60/wp57.pdf, p. 20.

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