CYIL Vol. 5, 2014

THE DEFINITION OF AGGRESSION AND THE USE OF FORCE the notion “act of aggression” in the Kampala definition differs from the jus ad bellum 1974 Definition of Aggression and in what way the Kampala definition of the crime of aggression departs from the jus ad bellum concept, including international customary law, and which implications it has or will have in the future. It is clear that prohibition of the “use of force” is a much broader subject than prohibition of “aggression” only. The definition of aggression is of course closely related to armed attack and self-defense. The focus of this work has been on aggression as an unlawful use of force and not on international criminal responsibility of individuals for crimes of aggression. Nevertheless the 2010 Kampala definition of the crime of aggression is important not only for the ICC but also for jus ad bellum . The related issues include the right of self-defense according to Art. 51 of the UN Charter and its relationship with the rules of customary international law. Such items as self-defense, including so called anticipatory or pre-emptive self-defense or so called accumulation-of-events doctrine, have been the subject of the Committee research too. The Committee has been dealing practically with all violations of Art. 2 (4) of the UNCharter prohibiting the use of force. Art. 2 (4) and Art. 51 as well have become the subject of permanent controversial interpretations and even misinterpretations. Art. 2 (4) is still a jus of cogens norm, despite frequent violations of it. In this connection various forms of military interventions (humanitarian intervention, intervention on invitation or with consent), Security Council (SC) authorization, and forcible protection of nationals abroad, environmental protection and the use of force in cyber operations are on the agenda of the Committee. This study does not go into the details of these problems and does not discuss the questions of domestic criminalization of aggression and implementation of the Kampala definition in domestic law, including the principle of complementarities. Article 2 (4) of the UN Charter is the basis of any definition of aggression. Not every unlawful use of armed force, of course, necessarily equates to an “act of aggression”. However, in the author’s view, it is rather difficult to determine any “act of aggression” which for responsible does not constitute at the same time a “crime of aggression” or “criminal act of aggression”. “Great Powers” will consider probably any armed use of force not only against their land territory but also against their ships, planes, forces etc. as a “crime of aggression”. It might be also be complicated to credibly recognize which acts of aggression have “serious” or “substantial” impact on violation of Art. 2 (4). The problem of the definition was and still is a matter of great controversy (even after Kampala). Attempts at defining aggression with the aim of prohibiting acts of aggression go back to the League of Nations and to the idea of a collective security system in Europe. The concept of “aggression” has been used together with the concepts of “force” and “armed attack”. The relationship between aggression and armed attack has never been clear enough. The legal meaning of aggression in the post-Charter era has got a new connotation. It is clear that there exists mutual interdependence between the notions aggression and armed attack. The term “aggression” had been considered to be too controversial even during the

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