On September 1977 Hungary and Czechoslovak signed the Gabcikovo-Nagymaros treaty, providing for a ‘join investment’ to produce electricity in a single and indivisible system.
Under strong pressure, 13 May 1989, Hungary suspended the works pending the completion of ecologic studies, on 27 October 1989 Hungary abandoned the works at Nagymaros.
Slovakia announced on 23 July 1991 that should Hungary continue to breach the Treaty she would proceed with a provisional solution [damming up the Danube unilaterally].
On November 1991 Slovakia commenced the construction in its territory of the provisional solution, but put it in operation on October 1992
On 19 May 1992 Hungary notify the termination of the Treaty, under the ground that Slovakia had made a material breach of the Treaty
Te case was referred to the ICJ by special agreement (1993)
The court was asked:
a) Whether Hungary was entitled to suspend and subsequently abandon, in 1989, the Nagymaros project
b) Whether Slovakia was entitled to proceed, November 1991, to the ‘provisional solution’ and to put into operation from October 1992 this system
c) What are the legal effects of the notification on May 1992 of the termination of the treaty by Hungary
40. Hungary contended that, although it did suspend or abandon certain works, on the contrar, it never suspended the application of the 1977 Treaty itself: to justified its conduct it relied essentially on a “state of ecological necessity”
46. The Vienna Convention of 1969 on the Law of Treaties … might be considered as a codification of existing customary law… This applies to the provisions of the Vienna Convention concerning the termination and the suspension of the operation of treaties, set forth in articles 60 to 62 (see Legal Consequences for States of the Continued presence of South Africa in Namibia …1971)
47. The law of Treaties and the law of State responsibility … obviously have a scope that is distinct. A determination of whether a convention is or is not in force, and whether it has been properly suspended or denounced, is to be made pursuant to the law of treaties. On the other hand, an evaluation of the extent to which the suspension or denunciation of a convention seen as incompatible with the law of treaties, involves the responsibility of the State which proceeded to it, is to be made under the law of State responsibility
The Vienna Convention of 1969 on the Law of Treaties confines itself to defining – in a limitative manner- the conditions in which a treaty may lawfully be denounced or suspended; while the effects of a denunciation or suspension seen as not meeting those conditions are, on the contrary, expressly excluded from the scope do the Convention by operation of Article 73. It is moreover well established that, when a State has committed an international wrongful act, its international responsibility is likely to be involved whatever the nature of the obligation it has failed to respect (cf Interpretation of Peace Treaties with, Bulgaria, Hungary and Romania, AO, 1950)
48. The Court cannot accept Hungary’s argument to the effect that, in 1989, in suspending and subsequently abandoning the works for which it was still responsible at Nagymaros…, it did not …suspend the application of the 1977 Treaty itself or reject that treaty. The conduct of Hungary …can only be interpreted as an expression of its unwillingness to comply with … the Treaty. The effect of Hungary´s conduct was to render imposible the accomplishment of works… described as “single and indivisible”
When [Hungary] invoked the state of necessity in an effort to justify its conduct… chose to place itself from the outset within the ambit of State Responsibility, thereby implying that in the absence of such a circumstance, its conduct would have been unlawful. The state of necessity … - supposing it to have been established - thus could not permit the conclusion that … obligations had ceased to be binding upon [Hungary]. It would only permit the affirmation that, under the circumstances, Hungary would not incur international responsibility by acting as it did
[Was there a state of necessity?]
51. State of necessity is a ground recognized by Customary International Law for precluding the wrongfulness of an act not in conformity with an international obligation. … State of necessity can only be invoked under certain strictly defined conditions which must be cumulatively satisfied; and the State concerned is not the sole judge of whether those conditions have been met
52. It must have been occasioned by an “essential interest” of the State to which is the author of the act conflicting with one of its international obligations; the interest must have been threatened by a “grave an imminent peril”; the act being challenged bust have been the “only means” of safeguarding that interest; that act must not have “seriously impair(ed) and essential interest” of the State toward which the obligation existed; and the State which is the author of that act must not have “contributed to the occurrence of the state of necessity” Those conditions reflect CIL
53. The Court has no difficult in acknowledging that the concerns expressed by Hungary for its natural environment… related to an “essential interest”
54. The word “peril” certainly evokes the idea of “risk”; that is precisely what distinguishes “peril” from material damage. But a state of necessity could not exist with a “peril” duly established at the relevant pint in time; the mere apprehension of a possible “peril” could not be suffice en that respect. … “peril”… has at the same time to be “grave” and “imminent”. “Imminence” is synonymous with “immediacy” or “proximity” and goes far beyond the concept of “possibility”… that does not exclude.. that a “peril” appearing in the long term might be held to be “imminent” as soon as it is established, at the relevant point in time.
57. Perils invoked by Hungary, without prejudging their possible gravity, were not sufficiently established in 1989, nor were they “imminent”; and Hungary had available to it at the time means of responding to these perceived perils other than the suspension and abandonment of works
Even if it had been established that there was. In 1989, a state of necessity linked to the performance of the 1977 Treaty, Hungary would not have been permitted to rely upon that state of necessity in order to justify its failure to comply with its treaty obligations, as it had helped, by act or omission to bring about it.
b) 67. [Slovakia] …maintained that [provisional solution] did not constitute internationally wrongful acts.
Slovakia invoked … “principle of approximate application” to justify the [provisional solution] It explained that his was the only possibility remaining to [Slovakia] “of fulfilling not only the purposes of the 1997 Treaty, but the continuing obligations to implement it in good faith”
68. Slovakia also maintained that Czechoslovakia was under a duty to mitigate the damage resulting from Hungary’s unlawful actions
69. Although Slovakia maintained that Czechoslovakia’s conduct was lawful, it argued in the alternative that [provisional solution] could still be justified as a countermeasure
75. Even if [the principle of approximate application] existed [whenever a legal instrument cannot be applied literally owing to the conduct of one of the parties, it must, without allowing that party to take advantage of its own conduct, be applied in a way approximating most closely to its primary object. To do that is to interpret an to give effect to the instrument- not to change it (Admissibility of Hearing of Petitioners by the Committee on South West Africa, separate opinion Judge Sir Hersch Lauterpacht, ICJ Reports 1956, p. 46)] existed, it could by definition only be employed within the limits of the treaty in question.
[by definition the 1977 Treaty could not be carried out unilaterally, so Slovakia committed a wrongful act]