‘A State cannot claim that the rules [pertaining to the acquisition of nationality] which it has [laid down by virtue of its internal laws] are entitled to recognition by another State unless it has acted in conformity with this general aim of making the legal bond of nationality accord with the individual's genuine connection (link) with the State which assumes the defence of its citizens by means of protection against other States. … According to the practice of States, to arbitral and judicial decisions and to the opinions of writers, nationality is a legal bond having as its basis a social fact of attachment, a genuine connection of existence, interests and sentiments, together with the existence of reciprocal rights and duties.’: Nottebohm Case 1955 I.C.J. Rep. 4 at 23 and 24. ‘In the Flegenheimer Claim … it was considered that a person who had only one nationality was not to be regarded as disentitled to rely on it against another state because he had no effective link with the state of nationality but only with a third state’: I Oppenheim 854 n. 12. See also Donner, The Regulation of Nationality in International Law (2nd ed.), Chap. 2; Weiss, Nationality and Statelessness in International Law (2nd ed.), 176–186.


Application of Genuine Formula to Ships:

With regard to ships, art. 5 of the Geneva Convention on the High Seas of 29 April 1958 (450 U.N.T.S. 82) requires that ‘[e]ach state shall fix the conditions for the grant of its nationality to ships, for the registration of ships in its territory, and for the right to fly its flag. Ships have the nationality of the state whose flag they are entitled to fly. There must exist a genuine link between the State and the ship; in particular, the state must effectively exercise its jurisdiction and control in administrative, technical and social matters over ships flying its flag.’ This position has been the subject of considerable criticism: ‘the assumption that the “genuine link” formula, invented for dealing with people, is capable of immediate application to ships and aircraft, smacks of a disappointing naiveté. … A provision which might seem to encourage governments to make subjective decisions whether or not to recognize the nationality of this aircraft or that vessel is clearly open for abuse and for that reason to grave criticism’: Jennings, The General Course on Principles of International Law, (1967) 121 Hague Recueil 327 at 463. Nevertheless, the provisions of art. 5 are replicated in art. 91 of the U.N. Convention on the Law of the Sea of 10 December 1982 (1833 U.N.T.S. 3), albeit, accompanied by an enumeration of the duties of the flag State in art. 94. See further flag of convenience.

Arts. 17–21 of the Chicago Convention on International Civil Aviation of 7December 1944 (15 U.N.T.S. 295) provide that the nationality of aircraft is governed by the State of registration. There does not appear to be a general requirement of a genuine link. However, ‘[i]n the absence of substantial connections the state of registry will not be in a position to ensure that the aircraft is operated in accordance with the Chicago Convention … Obviously the Nottebohm principle ought to apply to apply to aircraft as it does to ships …’: Brownlie, Principles of Public International Law, (6th ed.), 413. See further aircraft, nationality.

Reference: Genuine Link