CYIL vol. 9 (2018)

CEREN ZEYNEP PIRIM CYIL 9 ȍ2018Ȏ systems which makes this concept ‘a whole set of disconnected rules sharing only a common rationale’ 108 but its application may also create serious legal problems within the law of State succession to international responsibility. In other words, even in case where the principle of unjust enrichment is considered as a general principle of law, it remains controversial whether or not it meets the necessary conditions to be applied in the law of State succession. Firstly, on the basis of the overall conception of the principle, three conditions need to be met in order to talk about the unjust enrichment in cases of State succession: the State must have been enriched; the enrichment must have been unjust; the enrichment must be the reason of the impoverishment of another State. 109 Yet, even if the successor State is enriched because of the internationally wrongful act of the predecessor State, the ‘unjust’ nature of the enrichment seems to be debatable. This is because the enrichment can be considered unjust only when it results in an illegitimate impoverishment of another legal person, 110 thus when it happens without any valid legal ground. However, in cases of State succession, the link between the enrichment and the unjust nature of this enrichment, if that was the case under the legal order of the predecessor State, theoretically breaks at the date of succession. This is because the transfer of some rights and properties to the successor State is a consequence of the change of sovereignty over the territory, which constitutes a valid legal ground. Thus, the argument according to which the transfer of the enrichment to the successor State constitutes an unjust enrichment appears to be technically in contradiction with the general logic of the law of State succession. Secondly, even if it is agreed that the link between the enrichment and the unjust nature of this enrichment is not broken in State succession cases, the successor State, contrary to contractual obligations, ‘may not always be aware of the existence of the legal obligation to make restitution and may have acted on his belief that it was entitled to keep the enrichment’. 111 As noted by Sagaert within the context of municipal law issues, ‘while the impoverishment of the claimant is most frequently determined at the moment of its occurrence, the enrichment of the defendant remains undetermined until the claim in unjust enrichment is brought by the claimant’. 112 Thus, in cases where the successor State has lost the enrichment at the moment that it is charged with the obligation to make restitution, a conflict may arise between the prohibition of unjust enrichment and the principle of legal certainty according to which, amongst others, legitimate expectations must be protected. 113 Besides, according to the Iran-US Claims Commission, ‘what is sought as a remedy to unjust enrichment is the achievement of an acceptable economic equilibrium between the two parties. Such a goal is reached with the reestablishment of the previous economic position of the enriched party. Thus, the acceptable economic equilibrium is sought not simply by compensating the victim of the internationally wrongful acts but by first depriving the enriched party of its unjustly gained benefits, which are then awarded to the other party’. 114 This logic

108 Ibid. 109 These conditions are mentioned in Sea-Land Service award of the Iran-US Claims Tribunal, stated above.

110 Fombad (n 91) 123. 111 Sagaert (n 102) 160.

112 Ibid. 113 Ibid. 114 Flexi-Van Leasing, Inc. v. The Islamic Republic of Iran (Case 36) [1986] 12 Iran-USCTR 335, p. 353. See Dumberry (n 47) 266.

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