Dual Nationality, Persons of

persons who, in international law, are simultaneously nationals of two or more states, thus having dual nationality. Dual nationality may be due to (1) the birth of a child of nationals of a state that applies the principle of jus sanguinis in determining nationality on the territory of a state conforming to the principle of jus soli; (2) marriage of a woman to an alien if, under the law of her country, she is not deprived of her nationality after her marriage, whereas the law of the husband’s country automatically accords her his nationality; (3) the change of nationality of a person through naturalization if no preliminary agreement was made to the change of nationality on the part of the state of which the naturalized person had been a national. The question of the legal situation of such a person arises from the fact that each state, considering him to be its own citizen, may in principle require him to perform certain duties as its national (in particular, military duties). Furthermore, such a person may not refuse to carry out his civic duties on the territory of the state of which he is a national because of his duties to the other state.

Contemporary international law has no single, generally recognized solution to questions arising from dual nationality. Most states adopt a negative attitude to dual nationality. Attempts to settle this problem through the conclusion of bilateral or multilateral international agreements had already been made at the end of the 19th century (for example, the Bancroft agreements).

The problem of dual nationality has been examined repeatedly at international conferences. On Apr. 12, 1930, a convention on certain questions relating to the conflict of laws on nationality was concluded at The Hague. The convention confirmed that it is for each state to determine under its own law who are its nationals and what provision of its laws are to be recognized by other states insofar as is consistent with international conventions, international custom, and the principles of law generally recognized with regard to nationality. Each state may regard as its national a person who also possesses the nationality of another state, but it may not afford him diplomatic protection against a state whose nationality he also possesses. Within the territory of a third state, a person having more than one nationality must be treated as if he had only one. The convention also provides that a person possessing two nationalities acquired without any voluntary act on his part may renounce one of them with the authorization of the state whose nationality he desires to surrender. The same year a protocol was signed at The Hague relating to the military obligations of persons of dual nationality. It provided that a person possessing two or more nationalities who habitually resided in one of the countries whose nationality he possessed, and who was in fact most closely connected with that country, would be exempt from all military obligation in the other country or countries. Bilateral agreements relating to military obligations in cases of dual nationality also exist: for example, agreements of the United States with Norway (1930), with Sweden (1933), with Switzerland (1937), and with Finland (1939).

After World War II the problem of dual nationality was examined by the UN International Law Commission, which drew up draft conventions on the reduction of cases of dual nationality and their elimination in the future. These draft conventions provided that a state must refrain from granting citizenship to children not born in its territories; that a person acquiring the nationality of another state must renounce his previous nationality; that if a state’s legislation provides for the acquisition of the nationality of that state through marriage, divorce, or adoption, then the acquisition of the new nationality should entail the loss of the previous nationality; and that treaties between states on the cession of territory must contain provisions (for example, the option of nationality) guaranteeing that inhabitants of the ceded territory will not become persons with dual nationality. However, after a general discussion on its report, the International Law Commission concluded that the conditions necessary for the adoption of a convention on dual nationality did not yet exist, and the examination of the question was postponed for the time being.

The criterion of “effective nationality” is sometimes applied in cases of dual nationality. Thus, when members of the International Court of Justice of the UN or of the UN International Law Commission are elected, a member with dual nationality is deemed to be a national of the state in which he ordinarily exercises civil and political rights.

The Soviet Union has concluded bilateral agreements with most socialist countries regulating the question of dual nationality. These agreements provide for the elimination of cases of possible dual nationality through voluntary option of nationality and also for measures to prevent such cases of dual nationality in the future.