CYIL vol. 8 (2017)

TUOMAS HEIKKINEN – MARTIN FAIX CYIL 8 ȍ2017Ȏ State practice can be explained partly by the fact that TCSs often wish to act in secrecy in their attempts to influence the conduct of other States participating in the MMO. 48 Open naming and shaming might not serve the MMO’s goals and might not be as effective as measures taken in secrecy within the MMO’s framework. Moreover, lack of state practice can be explained by the fact that states are only bound to take measures that have chances of success, 49 and since in most cases their possibilities to influence transgressors are very limited it is not surprising that the state practice is sparse. Moreover, the question can be raised whether lack of widespread practice of TCSs does necessarily constitute a bar for confirming an extensive interpretation of Common Article 1 by subsequent practice. The relevant provision of the Vienna Convention on the Law of Treaties, i.e. Article 31(3)(b), requires that subsequent practice must establish agreement of the parties regarding its interpretation. However, such an agreement does not require active participation of all High Contracting Parties in relevant (subsequent) practice. It is sufficient that parties not actively exercising conduct (which can be considered as subsequent practice) have not raised an objection. 50 In other words, not all High Contracting Parties have to participate in the subsequent state practice. For creation of subsequent practice it is sufficient if the other High Contracting Parties remain silent and thus accept such practice. 51 Consequently, the lack of disapprovals or critique seems to point out the fact that High Contracting Parties have accepted the extensive interpretation. 52 Scope of Common Article 1 Concluding in favour of an extensive interpretation of Common Article 1, the question arises of what is the actual scope of the obligation. When and how are TCS obligated to ensure that the MMO fulfils its IHL obligations? Several authors have claimed that under Common Article 1, States have, instead of a duty to take positive actions to ensure respect, only a right to intervene in reaction to breaches of IHL. 53 However, the terms “ensure” and “undertake” are more likely to refer to an obligation instead of right to take measures. 54 Moreover, since it is clear that Common Article 1 issues binding obligations to TCS to ensure that their armed forces and personnel under their jurisdiction follow IHL, it is difficult to see why the same would not then be true for the external dimension of Common Article 1, 2005: protest of Spain in 1988 regarding Iraq-Iran war intentionally targeting civilians (p. 41); Croatian letter to UN Security Council in 1992 regarding Yugoslavia-Bosnia war intentionally targeting civilians (p. 153); German parliament protest in 1991 regarding Sudanese forces bombing of Red Cross and UN aid depots (p. 632). 48 KESSLER. op. cit., p. 505. 49 Cf. Chapter 3 of this contribution. 50 VILLIGER, Mark E., Commentary on the 1969 Vienna Convention on the Law of Treaties . Leiden: Martinus Nijhoff Publishers, 2009, p. 431, para. 22. 51 DÖRR, Oliver, SCHMALENBACH, Kristen, Vienna Convention on Law of Treaties: A Commentary. Springer- Verlag Berlin Heidelberg, 2012. p. 557. 52 A parallel with the practice of the Genocide Convention can support such a conclusion. In practice, States do not undertake all measures to stop genocides, but generally do not challenge the view that measures must be taken. The examples from the Srebrenica and Rwandan genocides show that not every State party to the Genocide convention is willing to take extreme measures in every case, similar to the Common Article 1 obligation to ensure respect of third parties. 53 KESSLER. op. cit., p. 500, KALSHOVEN. op. cit., p. 33. 54 GEISS. op. cit., p. 420, DÖRMANN, SERRALVO. op. cit., p. 723. 3.

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