The end of Cold War, marked by the collapse of the Soviet Union's communism has brought about the new political phenomenon. This phenomenon has given the impact not only to the dimension on International relations, but also, which even more important, to the evolution and progressive development of the world organization such as the United Nations. The application of a great mandatory sanctions under Chapter VII as for instance, which was never practiced during the Cold War period, had given a lot of legal perplexities, particularly the three components of that Chapter, namely action with respect to threat to the peace, breaches of the peace, and the last is the primary important, that are acts of aggression. Moreover, on the consideration of the question of ‘war of aggression' constituting one of the International Criminal Court's jurisdictions in the drafting of Statute of Rome, had been inconclusive, and no progress had been made. This article, therefore, may contribute to further development of the analysis of the core problem.