State responsibility but not a sufficient condition for reparation. There is a further element, associated with the exclusion of injury that is too “remote” or “consequential” to be the subject of reparation. In some cases, the criterion of “directness” may be used,462 in others “foreseeability”463 or “proximity”.464 But other factors may also be relevant: for example, whether State organs deliberately caused the harm in question, or whether the harm caused was within the ambit of the rule which was breached, having regard to the purpose of that rule.465 In other words, the requirement of a causal link is not necessarily the same in relation to every breach of an international obligation. In international as in national law, the question of remoteness of damage “is not a part of the law which can be satisfactorily solved by search for a single verbal formula”.466 The notion of a sufficient causal link which is not too remote is embodied in the general requirement in article 31 that the injury should be in consequence of the wrongful act, but without the addition of any particular qualifying phrase. (11) A further element affecting the scope of reparation is the question of mitigation of damage. Even the wholly innocent victim of wrongful conduct is expected to act reasonably when confronted by the injury. Although often expressed in terms of a “duty to mitigate”, this is not a legal obligation which itself gives rise to responsibility. It is rather that a failure to mitigate by the injured party may preclude recovery to that extent.467 The point was clearly made in this sense by ICJ in the Gabčíkovo-Nagymaros Project case: Slovakia also maintained that it was acting under a duty to mitigate damages when it carried out Variant C. It stated that “It is a general principle of international law that a party injured by the non-performance of another contract party must seek to mitigate the damage he has sustained”. 93 sis for the calculation of damages, it could not, on the other hand, justify an otherwise wrongful act.468 (12) Often two separate factors combine to cause damage. In the United States Diplomatic and Consular Staff in Tehran case,469 the initial seizure of the hostages by militant students (not at that time acting as organs or agents of the State) was attributable to the combination of the students’ own independent action and the failure of the Iranian authorities to take necessary steps to protect the embassy. In the Corfu Channel case,470 the damage to the British ships was caused both by the action of a third State in laying the mines and the action of Albania in failing to warn of their presence. Although, in such cases, the injury in question was effectively caused by a combination of factors, only one of which is to be ascribed to the responsible State, international practice and the decisions of international tribunals do not support the reduction or attenuation of reparation for concurrent causes,471 except in cases of contributory fault.472 In the Corfu Channel case, for example, the United Kingdom recovered the full amount of its claim against Albania based on the latter’s wrongful failure to warn of the mines even though Albania had not itself laid the mines.473 Such a result should follow a fortiori in cases where the concurrent cause is not the act of another State (which might be held separately responsible) but of private individuals, or some natural event such as a flood. In the United States Diplomatic and Consular Staff in Tehran case, the Islamic Republic of Iran was held to be fully responsible for the detention of the hostages from the moment of its failure to protect them.474 It would follow from such a principle that an injured State which has failed to take the necessary measures to limit the damage sustained would not be entitled to claim compensation for that damage which could have been avoided. While this principle might thus provide a ba- (13) It is true that cases can occur where an identifiable element of injury can properly be allocated to one of several concurrently operating causes alone. But unless some part of the injury can be shown to be severable in causal terms from that attributed to the responsible State, the latter is held responsible for all the consequences, not being too remote, of its wrongful conduct. Indeed, in the Zafiro claim the tribunal went further and in effect placed the Council in its decision 40 of 17 December 1996 (S/AC.26/Dec.40 (1996)). 462 As in Security Council resolution 687 (1991), para. 16. 463 See, e.g., the “Naulilaa” case (footnote 337 above), p. 1031. 464 For comparative reviews of issues of causation and remoteness, see, e.g., H. L. A. Hart and A. M. Honoré, Causation in the Law, 2nd ed. (Oxford, Clarendon Press, 1985); A. M. Honoré, “Causation and remoteness of damage”, International Encyclopedia of Comparative Law, A. Tunc, ed. (Tübingen, Mohr/The Hague, Martinus Nijhoff, 1983), vol. XI, part I, chap. 7; Zweigert and Kötz, op. cit. (footnote 251 above), pp. 601–627, in particular pp. 609 et seq.; and B. S. Markesinis, The German Law of Obligations: Volume II The Law of Torts: A Comparative Introduction, 3rd ed. (Oxford, Clarendon Press, 1997), pp. 95–108, with many references to the literature. 465 See, e.g., the decision of the Iran-United States Claims Tribunal in The Islamic Republic of Iran v. The United States of America, cases A15 (IV) and A24, Award No. 590–A15 (IV)/A24–FT, 28 December 1998, World Trade and Arbitration Materials, vol. 11, No. 2 (1999), p. 45. 466 P. S. Atiyah, An Introduction to the Law of Contract, 5th ed. (Oxford, Clarendon Press, 1995), p. 466. 467 In the WBC claim, a UNCC panel noted that “under the general principles of international law relating to mitigation of damages … the Claimant was not only permitted but indeed obligated to take reasonable steps to … mitigate the loss, damage or injury being caused” report of 15 November 1996 (S/AC.26/1996/5/Annex) (see footnote 461 above), para. 54. 468 Gabčíkovo-Nagymaros Project (see footnote 27 above), p. 55, para. 80. 469 United States Diplomatic and Consular Staff in Tehran (see footnote 59 above), pp. 29–32. 470 Corfu Channel, Merits (see footnote 35 above), pp. 17–18 and 22–23. 471 This approach is consistent with the way in which these issues are generally dealt with in national law. “It is the very general rule that if a tortfeasor’s behaviour is held to be a cause of the victim’s harm, the tortfeasor is liable to pay for all of the harm so caused, notwithstanding that there was a concurrent cause of that harm and that another is responsible for that cause … In other words, the liability of a tortfeasor is not affected vis-à-vis the victim by the consideration that another is concurrently liable.”: T. Weir, “Complex liabilities”, A. Tunc, ed., op. cit. (footnote 464 above), part 2, chap. 12, p. 43. The United States relied on this comparative law experience in its pleadings in the Aerial Incident of 27 July 1955 case when it said, referring to Article 38, paragraph 1 (c) and (d), of the ICJ Statute, that “in all civilized countries the rule is substantially the same. An aggrieved plaintiff may sue any or all joint tortfeasors, jointly or severally, although he may collect from them, or any one or more of them, only the full amount of his damage” (Memorial of 2 December 1958 (see footnote 363 above), p. 229). 472 See article 39 and commentary. 473 See Corfu Channel, Assessment of Amount of Compensation, Judgment, I.C.J. Reports 1949, p. 244, at p. 250. 474 United States Diplomatic and Consular Staff in Tehran (see footnote 59 above), pp. 31–33.