however, whether there is a body of rules of customary inter- national law, which would attach the desired legal consequences to the implementing provisions, In our opinion, making specification unnecessary. the legal relationship envisaged in Point One would be an international servitude. An international servitude is a permanent legal relationship whereby a State is entitled to exercise rights within part or the whole of the territory of another State, for a special purpose or interest relating to the territory in question, or whereby a State is obligated towards another State not to exercise certain of its ric¢chts within pert or the whole of its territory, for a special purpose or interest relating to this territory .7/ A servitude is a ius in rem, of indeterminate Curation, by changes of sovereignty in either State. which is unaffected The servitude contemplated in Point One is a paradygmatic case of a servi- tude in non faciendo, also called a negative servitude. The (footnote cont'd) into force on January 27, 1980. U.N. Conference on the Law of Treaties Official Records, Documents of the Conference (U.N. Doc. A/CONF. 39/27), p. 289. The United States is not a party to the Convention, but the principle of Article 26 is also part of customary international law. 4/ This is a slightly simplified version of the definition proposed by F. A. Vali, Servitudes of International Law, 2d edition (New York: Praeger, 1958), p. 309. nitions of international servitude, supra n. 2, vol. II, pp. 1173-1224. For other defi- see Whiteman, op. cit.,