CYIL Vol. 6, 2015

JAN LHOTSKÝ CYIL 6 ȍ2015Ȏ into such a grey area needs to be assessed individually considering the circumstances of each particular case. Among such grey areas the following situations can be mentioned: 5 • Unilateral humanitarian intervention, e.g. protection of an ethnic minority • Intervention in a civil war on the request of one of the parties • Operations aimed at the protection or rescue of nationals abroad • Anticipatory self-defence • Operations abroad against attacks emanating fromnon-State actors, e.g. terrorism • Reprisals, e.g. extensive reaction to a minor border issue It will be very difficult to legally assess such situations per se . Moreover, a mix of reasons may be seen in reality. Some intervention might be regarded as humanitarian, but in connection with positioning a new friendly leader who will conclude contracts advantageous for the intervening State or some of its leading persons, the consideration of such a situation becomes even more difficult. It is therefore necessary to stress that concerning the very general term ‘manifest violation’, the interpretational power given to the Court with regard to the grey area is simply huge. 4. Use of Force and Criminal Liability With regard to the use of force in international law, the following four groups of state behaviour can be distinguished: A. Use of force in accordance with international law In the case of self-defence or intervention in accordance with UN Security Council resolution under Chapter VII of the UN Charter, the use of force is legal and therefore cannot amount to a crime of aggression. B. Use of force within a grey area In general, a grey area means situations where reasonable legal arguments can be put to say that they are not illegal. However, as mentioned in the text above, these arguments need to be assessed individually and some criteria will have to be developed for distinguishing cases of a grey area that are not illegal from the ones that are in breach of international law. 6 The latter can amount to a crime of aggression. 5 See McDOUGHAL, Carrie. The Crime of Aggression of the Rome Statute of the International Criminal Court . New York: Cambridge University Press, 2013, pp. 155-157, 162; O’CONNEL, Mary Ellen – NIYAZMATOV, Mirakmal. What is Aggression? Comparing the Jus ad Bellum and the ICC Statute. Journal of International Criminal Justice , vol. 10, 2012, p. 201; 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. 19. 6 Some commentators suggest that by means of the term ‘manifest violation’, the grey areas are excluded. See WEISBORD, Noah. The Mens Rea of the Crime of Aggression. Washington University Global Studies Law Review , vol. 12, 2013, p. 506;

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