28 - 36 set out in law, the official will be required to carry out a specific act bestowing or withdrawing nationality.21 In non-automatic modes where an act of the State is required for acquisition of nationality, there will generally be a document recording that act, such as a citizenship certificate. Such documentation will be decisive in proving nationality. In the absence of such evidence it can be assumed that the necessary action was not taken and nationality not acquired.22 This assumption of non-citizenship can be set aside by subsequent statements, actions, or evidence by the competent authority indicating that nationality was actually conferred. PART ONE 33. (iv) Evaluating evidence of competent authorities in automatic modes of citizenship acquisition or loss of nationality 34. In cases where acquisition or loss of nationality occurs automatically, no State body is actively involved in the change of status and no active step is required of an individual. Such change occurs by operation of law (ex lege) when prescribed criteria are met. In most countries, nationality is acquired automatically either through birth on the territory or descent. Nationality is also acquired automatically by most individuals affected by State succession.23 Some laws provide for automatic loss of nationality when certain conditions are met, such as prescribed periods of residency abroad, or failure to register or make a declaration within a specific period. 35. Where nationality is acquired automatically, documents are typically not issued by the State as part of the mechanism. In such cases, it is generally birth registration that provides proof of place of birth and parentage and thereby provides evidence of acquisition of nationality, either by jus soli or jus sanguinis, rather than being the formal basis for the acquisition of nationality.24 36. When automatic modes of nationality acquisition or loss are under consideration, the competent authority is any State institution that is empowered to make a determination of an individual’s nationality status in 21 Please note that it cannot be concluded that an individual is a national (or has been deprived of nationality) until such a procedure has been completed, please see paragraph 50 below. 22 Applications for naturalization or other documents submitted through a non-automatic nationality procedure do not qualify as sufficient evidence regarding a State’s determination on that individual’s nationality status. 23 In some cases of State succession, however, citizenship of a successor State is not automatic and non-automatic modes of citizenship acquisition are employed instead. Please see the International Law Commission, Articles on the Nationality of Natural Persons in relation to the Succession of States with commentaries, 3 April 1999, http://www.refworld.org/docid/4512b6dd4.html, for an overview of State practice. 24 Jus soli and jus sanguinis refer to the two main principles governing acquisition of nationality in the legal systems of States, on the basis of place of birth and descent from a national, respectively. 15