40 Report of the International Law Commission on the work of its fifty-first session cases of fraud, negligence or serious error.106 Moreover, the judgment in the Nottebohm case only dealt with the admissibility of a claim for diplomatic protection and did not imply that a person could be generally treated as stateless. (4) In practice, different tests for determining the competence of the successor State to attribute its nationality on certain persons have been considered or applied, such as habitual residence or birth. Thus, for example, the peace treaties after the First World War as well as other instruments used as a basic criterion that of habitual residence.107 But, as has been pointed out, “[a]lthough habitual residence is the most satisfactory test for determining the competence of the successor State to impress its nationality on specified persons, it cannot be stated with assurance to be the only test admitted in international law”.108 Some authors have favoured the test of birth in the territory affected by the succession as proof of an effective link with the successor State.109 In recent dissolutions of States in Eastern Europe, the main accent was often put on the “citizenship” of the component units of the federal State that disintegrated, which existed in parallel to federal nationality.110 (5) The term “link” in paragraph 1 of article 19 is qualified by the adjective “effective”. The intention was to use the terminology of ICJ in the Nottebohm case.111 Although the question of non-opposability of nationality not based on an effective link is a more general one, the scope of application of paragraph 1 is limited to the nonopposability of a nationality acquired or retained following a succession of States. (6) Paragraph 2 deals with the problem that arises when a State concerned denies a person concerned the right to retain or acquire its nationality by means of discriminatory legislation or an arbitrary decision and, as a consequence, such person becomes stateless. As already stated, international law cannot correct the deficiencies of internal acts of a State concerned, even if they result in statelessness. This, however, does not mean that other 106 Decision of 20 September 1958 (UNRIAA, vol. XIV (Sales No. 1965.V.4), p. 327). 107 The peace treaties of Saint-Germain-en-Laye (Treaty of Peace between the Allied and Associated Powers and Austria, Treaty between the Principle Allied and Associated Powers and Czechoslovakia and the Treaty between the Principle Allied and Associated Powers and the Serb-Croat-Slovene State) and of Trianon (Treaty of Peace between the Allied and Associated Powers and Hungary), however, adopted the criterion of pertinenza (indigénat), which did not necessarily coincide with habitual residence. 108 O’Connell, State Succession in Municipal Law . . . (footnote 43 above), p. 518. 109 In the case of Romano v. Comma, in 1925, the Egyptian Mixed Court of Appeal relied on this doctrine when it held that a person born in Rome and resident in Egypt became, as a result of the annexation of Rome in 1870, an Italian national (Annual Digest of Public International Law Cases, 1925-1926 (London, 1929), vol. 3, p. 265, case No. 195). 110 See paragraphs (5) to (10) of the commentary to draft article 20 proposed by the Special Rapporteur in his third report (footnote 10 above). 111 It must be noted that, in the English version of the Judgment, the Court also uses the expression “genuine connection”, the equivalent of which is rattachement effectif in the French version (see footnote 104 above). States are simply condemned to a passive role. There have indeed been instances where States did not recognize any effect to the legislation of another State aimed at denying its nationality to certain categories of persons, albeit in a context other than a succession of States: e.g. such was the position of the Allies with respect to the Decree of 25 November 1941, in pursuance of the Law for the Protection of German Blood and German Honour (Reich Citizenship Law), denationalizing German Jews.112 (7) The provision of paragraph 2 is, however, not limited to the case where statelessness results from an act of a State concerned. It also applies where a person concerned has, by his or her negligence, contributed to such situation. (8) The purpose of paragraph 2 is to alleviate, not to further complicate, the situation of stateless persons. Accordingly, this provision is subject to the requirement that the treatment of such persons as nationals of a particular State concerned be for their benefit, and not to their detriment. In practical terms, this means that other States may extend to these persons a favourable treatment granted to nationals of the State in question. However, they may not, for example, deport such persons to that State as they could do with its actual nationals (provided that there would be legitimate reasons for such action). PART II PROVISIONS RELATING TO SPECIFIC CATEGORIES OF SUCCESSION OF STATES Commentary (1) The provisions of Part II are divided into four sections devoted to specific categories of succession of States, namely “Transfer of part of the territory”, “Unification of States”, “Dissolution of a State” and “Separation of part or parts of the territory”. The identification of the rules governing the distribution of individuals among the States involved in a succession derives in large part from the application of the principle of effective nationality to a specific case of succession of States. (2) As regards the criteria used for establishing the rules concerning the attribution of the nationality of the successor State, the withdrawal of the nationality of the predecessor State and the recognition of a right of option in Part II, the Commission, on the basis of State practice, has given particular importance to habitual residence.113 112 See Lauterpacht, loc. cit. (footnote 52 above). See paragraphs 50 to 81 of the second report (footnote 7 above). See also paragraph (4) of the commentary to article 5 above. As regards the nationality laws of newly independent States, it must be observed that, while some countries applied residence as a basic criterion, others employed criteria such as jus soli, jus sanguinis and race. See Y. Onuma, “Nationality and territorial change: in search of the state of the law”, The Yale Journal of World Public Order, vol. 8, No. 1 (fall 1981), p. 1, at pp. 15-16; and J. de Burlet, Nationalité des personnes physiques et décolonisation: Essai de contribution à la théorie de la succession d’États, Bibliothèque de la Faculté de droit de l’Université catholique de Louvain, vol. X (Brussels, Bruylant, 1975), pp. 144-180. 113