The Vienna Convention contains general provisions on suspension and termination of treaties, in particular Articles 54 to 62 VCLT.
Before I am going to discuss the infamous Gabčíkovo-Nagymaros (pronunciation: Gab-chi-co-vah/ Nagee-marosh) case, I will first make a disctinction between formal and substantive grounds for termination or suspension of a treaty.
1.1. Formal grounds for termination or suspension of a treaty
The formal grounds for termination of treaties is provided by articles 54 to 59 VCLT. These include termination in conformity with the provisions of the treaty and termination by consent of all the parties after consultation (art. 54) and termination or suspension of the operation of the treaty implied by conclusion of a later treaty (art. 59).
1.2. Material grounds for termination
Articles 60 to 62 VCLT provide the substantive or material grounds for termination or suspension of a treaty. The ICJ affirms that the rules laid down by the Vienna Convention on
the Law of Treaties concerning termination of a treaty relationship on account of breach, may in many respects be considered as a codification of existing customary law on the subject (see the Namibia Advisory Opinion of 1971, p. 47).
Note that articles 60-62 VCLT provide three options to justify unilateral termination of a treaty:
1. inadimplenti non est adimplendum;
2. force majeure;
3. rebus sic stantibus;
The first one being the actual "material breach" by the other contracting party.
2. Material grounds for termination or suspension of a treaty and Gabčíkovo-Nagymaros Does Hungary's termination of the 1977 Treaty between Hungary and Czechoslovakia, meet the requirements under Article 60 to 62 VCLT? This is the main question in the G-N case, for Hungary invokes no less than five grounds in an attempt to justify its unilateral termination of the Treaty.
These grounds are, in no particular order: a state of necessity, material breach of the treaty by Czechoslovakia, impossibility of performance of the treaty, a fundamental change of circumstances and the development of new norms of international environmental law. Before I am going to discuss the state of necessity, I will highlight the three material grounds that are covered by art. 60-62 VCLT.
2.1. Inadimplenti non est adimplendum (art. 60 VCLT)
A material breach of a bilateral treaty by one of the parties entitles the other to invoke the breach as a ground for terminating or suspending the treaty, art. 60 (1). A material breach is, as follows from
art. 60(3)(a)(b):
a. a repudiation of the treaty not sanctioned by the present Convention;
b. the violation of a provision essential to the accomplishment of the object or purpose of the treaty.
In the Gabĉikovo-Nagymaros case, the Court has to decide on whether Hungary's invocation of material breach by Czechoslovakia is justified:
It is up to the Court to decide, whether there has been a material breach, rather than just a grave breach:
The Court is of the view that it is only a material breach of the treaty itself, by a State party to the treaty, which entitles the other party to rely on it as a ground for terminating the treaty. The violation of other treaty rules of general international law may justify the taking of certain [counter]measures by the injured State, but it does not constitute a ground for termination under the law of treaties (para 106);
Hungary, by its own conduct, had prejudiced its right to terminate the Treaty; this would still have been the case even if Czechoslovakia, by the time of the purported termination, had violated a provision essential to the accomplishment of the object and purpose of the Treaty (para 110).
The material breach must have taken place in order to justly invoke such breach:
Hungary's main argument for invoking a material breach of the Treaty was the construction and putting into operation of Variant C [by Czechoslovakia]. As the Court has found, Czechoslovakia violated the Treaty only when it diverted the waters [...]. Czechoslovakia did not act unlawfully in constructing the works that would lead to the putting into operation of Variant C.
In the Court's view, the notification of termination by Hungary was premature. No breach of the Treaty had yet taken place and Hungary was, therefore, not entitled to invoke such breach as a ground for termination (para 108).
Czechoslovakia has breached its treaty obligations, but only when putting Variant C into operation (para 78 and 82). The preparations on the territory of Czechoslovakia had not yet led to a material breach, therefore, Hungary's invocation of a material breach by Czech. was premature. Thus, the Court rejects the invocation of material breach/ inadimplenti by Hungary.
2.2 Supervening impossibility of performance (art. 61 VCLT) (force majeure/ Act of God)
As described by Article 61 VCLT, a party may invoke the impossibility of performance as a ground for termination of a treaty, if the impossibility results from the permanent disappearance or destruction of an object, indispensable for the execution of the treaty. A temporary impossibility is not sufficient for termination of the treaty. If the impossibility of performance results from that party's own breach, the ground of supervening impossibility may not be invoked (art. 61 (2) VCLT). Judging the G-N case, this means that Hungary was not entitled to invoke Article 61 para 1 VCLT, for the impossibility of performance stems from Hungary's own "omission" (para 102-103). In other words, this ground implies a mere "Act of God".
2.3. Rebus sic stantibus: fundamental change of circumstances (art. 62 VCLT)
A fundamental change of circumstances with regard to those existing at the time of the conclusion of the treaty, which was completely unforeseen by the parties, may not be invoked, para 1, unless:
a. the existence of those circumstances constituted an essential basis of the consent of the parties to be bound by the treaty;
b. the effect of the change is radically to transform the extent of obligations still to be performed.
You'll have noticed the essential grounds for invoking a fundamental change of circumstances: the circumstances have to be fundamentally different, compared to the original circumstances at the time of the conclusion, and the change itself has to be completely unforeseen by either of the parties. Minor changes that do not relate to the consent to be bound or to the obligations to be performed, cannot justify the invocation of a fundamental change. A de facto material breach may be invoked.
In G-N, the Court recalls the Fisheries Jurisdiction case on Article 62 of the VCLT. As Hungary argued, the events which would have constituted a fundamental change, were specified as profound changes of a political nature, the Project's diminishing economic viability, the progress of environmental knowledge and new norms of environmental law.
In the Court's view, the prevalent political conditions were thus not so closely linked to the object and purpose of the Treaty, that they constituted an essential basis for the consent of parties and, in changing, radically altered the extent of obligations still to be performed. The profitablity of the Project was not bound to such an extent that the obligations of the parties would have radically transformed as a result. The development of environmental knowlegde and law cannot be said to have been completely unforeseen. The changed circumstances advanced by Hungary are not of such a nature, that their effect would radically transform the extent of the obligations to accompish Project G-N. Article 62 of the VCLT is a clear indication that the plea can only apply in exceptional cases (para 104).
3. State of necessity (art. 33 (now: 25) of the Draft Articles on State Responsibility)
Not under the scope of the VCLT, but under the scope of the International Responsibility of States, the Court will consider the question of whether there was a state of necessity which would have permitted Hungary to suspend and abandon works that it was commited to perform in accordance with the Treaty.
A state of necessity may be invoked if:
a. the act was the only means of safeguarding an essential interest of the State against a grave and imminent peril;
b. the act did not seriously impair an essential interest of the State towards which the obligation existed.
In the G-N case, the Court considers, first of all, that the state of necessity is a ground, recognized by customary internationa law for precluding the wrongfulness of an act not in conformity with an international obligation. Such ground can only be accepted on an exceptional basis. The state of necessity can only be invoked under certain strictly defined conditions which must be cumulatively satisfied. The State concerned is not the sole judge of whether those conditions have been met (para 51-52).
The Commission indicated that one should not, in [..] context, reduce an "essential interest" to a matter only of the "existence" of the State and that the whole case has to be judged in the light of the particular case (para 53) (i.o. words: the existence has to be objective) .
However serious the uncertainties might have been, they could not, alone, establish the objective existence of a "peril" in the sense of a component element of a state of necessity. The mere apprehension of a possible peril could not suffice. The extremely grave and imminent peril must have been a threat to the interest at the actual time (para 54).
Considering the situation at Nagymaros (Hungary), the Court notes that the dangers were mostly of a long-term nature and, above all, that they remained uncertain. The peril invoked by Hungary had already materialized to a large extent for a number of years, so that it could not, in 1989, represent a peril arising entirely out of the G-N Project. Even if the construction of the G-N Project would have created serious risks, Hungary had means available to it, other than suspension and abandonment of the works, of responding to that situation (para 55).
However grave it might have been, it would accordingly have been difficult to see the alleged peril as sufficiently certain and therefore "imminent" in 1989 . Hungary should have resorted to other means in order to respond to the dangers that it apprehended. In particular, within the framework of the original Project, Hungary seemed to be in position to control (para 56).
At the time of concluding the Treaty, Hungary was presumably aware of the situation as then known, when it assumed its original obligations. The Court cannot fail to note the positions taken by Hungary after the entry into force of the 1977 Treaty. Hungary asked that the works should go forward more slowly, then asked for the works to be speeded up, only to suspend and abandon them three months later.
The conclusion is that Hungary would not have been permitted to rely upon the 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 it about (para 57).
