responsibilities of States for women and children in the northern Syrian Arab Republic. 6. Consistent with her mandate, the UN Special Rapporteur is deeply concerned to ensure that States (including the UK) adhere to their international law obligations in cases concerning foreign fighters abroad, particularly those involving women and children. The prohibition of the arbitrary deprivation of citizenship provides essential protection to such individuals. The due process guarantees that are inherent in this prohibition are especially significant in cases (i) involving a risk of statelessness, (ii) in which the deprivation of nationality is made in absentia and (iii) in which the deprivation is made on the basis of broad and vague statutory language. The UN Special Rapporteur is particularly concerned to ensure that due process guarantees are upheld in those cases. C. The prohibition on arbitrary deprivation of citizenship under Article 15(2) UDHR 7. International law has a well-established role in limiting States’ regulation of nationality. Even though the definition and conferral of nationality is within the sovereign domain of States, international courts and tribunals have long recognised that international law imposes express limits on States’ powers, both through customary international law (“CIL”) and treaty obligations.6 As the International Law Commission put it, “the competence of States in this field may be exercised only within the limits set by international law”.7 With the rapid development of international human rights law and the advent of nationality as a human right, the limitations on the State’s exercise of these powers have become greater.8 8. The starting point as to the source of the prohibition on arbitrary deprivation of citizenship is the UDHR itself. Adopted by the UN General Assembly in 1948, the UDHR laid down “a common standard of achievement for all people and all nations”.9 Given that the status of nationality confers a collection of rights,10 it is no surprise that the right to nationality has a prominent place within the UDHR (Article 15(1)). That right sits alongside the prohibition of its arbitrary deprivation (Article 15(2), which provides that “No one shall be arbitrarily deprived of his nationality nor denied the right to change his nationality.” 9. The UK played an instrumental role in the introduction of the prohibition into the UDHR. Along with India, the UK made an early proposal to substitute the language of what is now Nationality Decrees Issued in Tunis and Morocco (Permanent Court of International Justice), Ser. B, No. 4, Advisory Opinion, 7 February 1923, pp. 23-24; Georges Pinson v United Mexican States (1928) 5 UNRIAA 327, p. 364 (FranceMexico Claims Commission). See also Hague Convention on Certain Questions Relating to the Conflict of Nationality Laws (1930) 179 LNTS 89, Article 1. 6 ILC, ‘Draft Articles on Nationality of Natural Persons in relation to the Succession of States (with commentaries)’ (1999) II(2) YBILC, p. 24, para. 3. See also ‘Human Rights and arbitrary deprivation of nationality: Report of the Secretary-General’, UN Doc. A/HRC/13/34, 14 December 2009, para. 19. 7 Proposed Amendments to the Naturalization Provision of the Constitution of Costa Rica, Inter-American Court of Human Rights, Advisory Opinion OC-4/84, 19 January 1984, Ser. A, No. 4, para. 32; Case of the Girls Yean and Bosico v Dominican Republic, Inter-American Court of Human Rights, Judgment, 8 September 2005, Ser. C, No. 130, para. 138. 8 9 UDHR (adopted in UN GA Resolution 217(A) (III), UN Doc. A/810, p. 71), preamble. For this reason, it is often described as the ‘right to have rights’: see Pham v Secretary of State for the Home Department [2018] EWCA Civ 2064, [2019] 1 WLR 2070, paras 30 and 49; see also Trop v Dulles 356 US 86 (1958), pp. 101-102. 10 3