§ 296. As emigration comprises the voluntary removal of an individual from his home State with the intention of residing abroad, but not necessarily with the intention of renouncing his nationality, it is obvious that emigrants may well retain their nationality. Emigration is in fact entirely a matter of internal legislation of the different States. Every State can fix for itself the conditions under which emigrants lose or retain their nationality, as it can also prohibit emigration altogether, or can at any moment request those who have emigrated to return to their former home, provided the emigrants have retained their nationality of birth. And it must be specially emphasised that the Law of Nations does not and cannot grant a right of emigration to every individual, although it is frequently maintained that it is a "natural" right of every individual to emigrate from his own State.[617]
[617] Attention ought to be drawn to the fact that, to ensure the protection of the interests of emigrants and immigrants from the moral, hygienic, and economic view, the Institute of International Law, at its meeting at Copenhagen in 1897, adopted a body of fourteen principles concerning emigration under the heading "Vœux relatifs à la matière de l'émigration"; see Annuaire, XVI. (1897), p. 276. See also Gargas in Z.V. V. (1911), pp. 278-316.
III MODES OF ACQUIRING AND LOSING NATIONALITY
Vattel, I. §§ 212-219—Hall, §§ 67-72—Westlake, I. pp. 213-220—Lawrence, §§ 94-95—Halleck, I. pp. 402-418—Moore, III. §§ 372-473—Taylor, §§ 176-183—Walker, § 19—Bluntschli, §§ 364-373—Hartmann, § 81—Heffter, § 59—Stoerk in Holtzendorff, II. pp. 592-630—Gareis, § 55—Liszt, § 11—Ullmann, §§ 110 and 112—Bonfils, Nos. 417-432—Despagnet, Nos. 318-327—Pradier-Fodéré, III. Nos. 1646-1691—Rivier, I. pp. 303-306—Calvo, II. §§ 541-654, VI. §§ 92-117—Martens, II. §§ 44-48—Fiore, Code, Nos. 660-669—Foote, "Private International Jurisprudence" (3rd ed. 1904), pp. 1-52—Dicey, "Conflict of Laws" (1896), pp. 173-204—Martitz, "Das Recht der Staatsangehörigkeit im internationalen Verkehr" (1885)—Cogordan, "La nationalité, &c" (2nd ed. 1890), pp. 21-116, 317-400—Lapradelle, "De la nationalité d'origine" (1893)—Berney, "La nationalité à l'Institut de Droit International" (1897)—Bisocchi, "Acquisto e perdita della Nazionalità, &c." (1907)—Sieber, "Das Staatsbürgerrecht in internationalem Verkehr," 2 vols. (1907)—Lehr, "La nationalité dans les principaux états du globe" (1909), and in R.I. 2nd Ser. X. (1908), pp. 285, 401, and 525.
In 1893 the British Government addressed a circular to its representatives abroad requesting them to send in a report concerning the laws relating to nationality and naturalisation in force in the respective foreign countries. These reports have been collected and presented to Parliament. They are printed in Martens, N.R.G. 2nd Ser. XIX. pp. 515-760.
Five Modes of Acquisition of Nationality.
§ 297. Although it is for Municipal Law to determine who is and who is not a subject of a State, it is nevertheless of interest for the theory of the Law of Nations to ascertain how nationality can be acquired according to the Municipal Law of the different States. The reason of the thing presents five possible modes of acquiring nationality, and, although no State is obliged to recognise all five, nevertheless all States practically do recognise them. They are birth, naturalisation, redintegration, subjugation, and cession.
Acquisition of Nationality by Birth.
§ 298. The first and chief mode of acquiring nationality is by birth, for the acquisition of nationality by another mode is exceptional only, since the vast majority of mankind acquires nationality by birth and does not change it afterwards. But no uniform rules exist according to the Municipal Law of the different States concerning this matter. Some States, as Germany and Austria, have adopted the rule that descent alone is the decisive factor,[618] so that a child born of their subjects becomes ipso facto by birth their subject likewise, be the child born at home or abroad. According to this rule, illegitimate children acquire the nationality of their mother. Other States, such as Argentina, have adopted the rule that the territory on which birth occurs is exclusively the decisive factor.[619] According to this rule every child born on the territory of such State, whether the parents be citizens or aliens, becomes a subject of such State, whereas a child born abroad is foreign, although the parents may be subjects. Again, other States, as Great Britain[620] and the United States, have adopted a mixed principle, since, according to their Municipal Law, not only children of their subjects born at home or abroad become their subjects, but also such children of alien parents as are born on their territory.
[618] Jus sanguinis.