World Court Digest

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I.	Substantive International Law - First Part
4.	SUBJECTS OF INTERNATIONAL LAW
4.2.	States
4.2.6.	Succession of States

¤ Gabcíkovo-Nagymaros Project
(Hungary / Slovakia)
Judgment of 25 September 1997
I.C.J. Reports 1997, p. 7

[pp. 71-72] 123. The Court does not find it necessary for the purposes of the present case to enter into a discussion of whether or not Article 34 of the 1978 Convention reflects the state of customary international law. More relevant to its present analysis is the particular nature and character of the 1977 Treaty. An examination of this Treaty confirms that, aside from its undoubted nature as a joint investment, its major elements were the proposed construction and joint operation of a large, integrated and indivisible complex of structures and installations on specific parts of the respective territories of Hungary and Czechoslovakia along the Danube. The Treaty also established the navigational regime for an important sector of an international waterway, in particular the relocation of the main international shipping lane to the bypass canal. In so doing, it inescapably created a situation in which the interests of other users of the Danube were affected. Furthermore, the interests of third States were expressly acknowledged in Article 18, whereby the parties undertook to ensure "uninterrupted and safe navigation on the international fairway" in accordance with their obligations under the Convention of 18 August 1948 concerning the Regime of Navigation on the Danube.

In its Commentary on the Draft Articles on Succession of States in respect of Treaties, adopted at its twenty-sixth session, the International Law Commission identified "treaties of a territorial character" as having been regarded both in traditional doctrine and in modern opinion as unaffected by a succession of States (Official Records of the United Nations Conference on the Succession of States in respect of Treaties, Vol. III, Doc. A/CONF 80/16/Add.2, p. 27, para. 2). The draft text of Article 12, which reflects this principle, was subsequently adopted unchanged in the 1978 Vienna Convention. The Court considers that Article 12 reflects a rule of customary international law; it notes that neither of the Parties disputed this. Moreover, the Commission indicated that "treaties concerning water rights or navigation on rivers are commonly regarded as candidates for inclusion in the category of territorial treaties" (ibid., p. 33, para. 26). The Court observes that Article 12, in providing only, without reference to the treaty itself, that rights and obligations of a territorial character established by a treaty are unaffected by a succession of States, appears to lend support to the position of Hungary rather than of Slovakia.
However the Court concludes that this formulation was devised rather to take account of the fact that, in many cases, treaties which had established boundaries or territorial régimes were no longer-in force (ibid., pp. 26-37). Those that remained in force would nonetheless bind a successor State.

Taking all these factors into account, the Court finds that the content of the 1977-Treaty indicates that it must be regarded as establishing a territorial régime within the meaning of Article 12 of 1978 Vienna Convention. It created rights and obligations "attaching to" the parts of the Danube to which it relates; thus the Treaty itself cannot be affected by a succession of States. The Court therefore concludes that the 1977 Treaty became binding upon Slovakia on 1 January 1993.

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