Purchased nationality: A functional approach to address the risks associated with its recognition by other states and the exercise of diplomatic protectionNacionalidad adquirida: Un enfoque funcional para abordar los riesgos asociados a su reconocimiento por otros estados y al ejercicio de la protección diplomáticaNationalité achetée: Une approche fonctionnelle pour traiter les risques associés à sa reconnaissance par d’autres États et à l’exercice de la protection diplomatiqueSantiago Yarahuán Dodero1 https://orcid.org/0009-0008-4447-2428Instituto Tecnológico y de Estudios Superiores de Monterrey. MéxicoCorreo electrónico: santiago.yarahuan@outlook.comRecepción: 16 de mayo de 2024Aceptación: 24 de agosto de 2024Publicación: 20 de noviembre de 2024DOI: https://doi.org/10.22201/iij.24487872e.2025.25.19048Abstract: This paper focuses on reviewing the validity of citizenship by investment programmes with international law. This paper will demonstrate that what the Second Judgement of the Not-tebohm Case of the International Court of Justice really intended was to rule against naturaliza-tions granted contrary to the general principle of law prohibiting abuses of rights. Moreover, 1 Head of Departamen at the Legal Office for International Trade Law of the Ministry of Economy of Mexico. The opinions expressed in this paper are personal opinions of the author and do not reflect the opinions/posture of the Mexican government or any firm/company/organization/institution where the author may collaborate in the future.

2 de 35Anuario Mexicano de Derecho Internacional, vol. 25, núm. 25, 2025, e19048Santiago Yarahuán DoderoPurchase nationality: A functional approach to address the risks associated with its recognition by other states and the exercise of diplomatic protectionthis paper will provide a functional approach to citizenship by investment programmes that will enable States to attract investors while naturalizing them in accordance with international law, as they will generate significant links, avoiding the risks associated with the recognition of their nationality by other States and within the scope of diplomatic protection.Keywords: nationality; citizenship by investment; Nottebohm case; genuine link; predominant link; good faith; abuse of rights; international law.Resumen: El presente artículo se centra en la revisión de la conformidad de los programas de ciudadanía por inversión con el Derecho internacional. Este artículo demostrará que lo que real-mente pretendía la Segunda Sentencia del Caso Nottebohm de la Corte Internacional de Justicia era pronunciarse en contra de las naturalizaciones concedidas en contra del principio general del derecho que prohíbe los abusos de derechos. Además, este artículo ofrecerá un enfoque funcio-nal para los programas de ciudadanía por inversión que permitirá a los Estados atraer inversores al tiempo que los naturalizan de conformidad con el Derecho internacional, ya que generarán vínculos significativos, evitando riesgos asociados al reconocimiento de nacionalidad por parte de otros Estados y en el ámbito de la protección diplomática.Palabras clave: nacionalidad; ciudadanía por inversión; caso Nottebohm; vínculo genuino;vínculo predominante; buena fe; abuso de derechos; derecho international.Résumé: Cet article porte sur l’examen de la validité des programmes de citoyenneté par l’in-vestissement au regard du droit international. Il démontre que l’intention réelle du deuxième arrêt de la Cour Internationale de Justice dans l’affaire Nottebohm était de s’opposer aux natu-ralisations accordées en violation du principe général du droit interdisant les abus de droit. En outre, cet article propose une approche fonctionnelle des programmes de citoyenneté par l’in-vestissement qui permettra aux États d’attirer les investisseurs tout en les naturalisant confor-mément au droit international, puisqu’ils généreront des liens significatifs, en évitant les risques liés à la reconnaissance de leur nationalité par d’autres États et dans le cadre de la protection diplomatique.Mots-clés: nationalité; citoyenneté par l’investissement; affaire Nottebohm; lien réel; lien pré-dominant; bonne foi; abus de droit; droit international.Summary: I. Introduction. II. Problem contextualization. III. The Nottebohm Case.I V. Predominant nationality for diplomatic protection in cases of dual-nationality. V. A func-tional approach for purchased nationality. VI. Conclusions. VII. Bibliography.I. IntroductionIn today’s world of economic globalization and migration, nationality remains a centerpiece of global relations, as it defines the permanent population be-longing to a State, comprising a legal relationship between the individual

3 de 35Anuario Mexicano de Derecho Internacional, vol. 25, núm. 25, 2025, e19048Santiago Yarahuán DoderoPurchase nationality: A functional approach to address the risks associated with its recognition by other states and the exercise of diplomatic protectione-ISSN 2448-7872DOI: https://doi.org/10.22201/iij.24487872e.2025.25.19048Esta obra está bajo una Licencia Creative Commons Reconocimiento-NoComercial 4.0 Internacionaland the State.2 In this sense, international law has conferred on States the sovereign right to decide, in accordance with their laws, who are their own nationals and to protect them. Despite a long-standing understanding of the meaning and purpose of nationality, a number of States, in an effort to obtain significant economic benefits and stimulate development, decided to intro-duce citizenship by investment programmes to offer high-net-worth indi-viduals the possibility of acquiring their nationalities in order to benefit from the advantages their passports possess. Naturally, this scheme has generated a considerable amount of controversy, as it does not require investors to estab-lish any significant ties to the countries, which runs counter to the genuine link theory of the famous Second Phase Judgment of the Nottebohm case of the International Court of Justice (ICJ).Is the genuine link theory legitimized and capable of assessing whether a State abuses its right to decide who its nationals are and its nationality law in light of a citizenship by investment programme? This paper holds that Not-tebohm’s genuine link theory is a solid and legitimate precedent to condemn naturalizations carried out in violation of the general principle of law of good faith, as it provides a limit to State discretion, which preserves the values as-sociated with the sacrosanct concept of nationality. Therefore, the objective of this paper is to propose a functional approach to citizenship by investment programmes that will enable States to attract investors while naturalizing them in accordance with international law. I will proceed in the following way: first (II, infra), I will contextualize the problem; in a second section (III, infra), I will examine the Nottebohm case, in order to understand its reasoning and determination under the lens of a general rule of law and as a violation of the general principle of law prohibit-ing abuses of rights, as well as the criticisms of its judgment; then (IV, infra), an explanation of the predominant nationality principle in dual nationality cases will be addressed; fourthly (V, infra), I will offer a functional approach to acquired nationality in order to bring these programmes in line with in-ternational law; and lastly (VI, infra), I will offer some concluding remarks.2 Dörr, Oliver, “Nationality”, Max Planck Encyclopedias of International Law, 2019, ¶ 1.

4 de 35Anuario Mexicano de Derecho Internacional, vol. 25, núm. 25, 2025, e19048Santiago Yarahuán DoderoPurchase nationality: A functional approach to address the risks associated with its recognition by other states and the exercise of diplomatic protectionII. Problem contextualizationSince the 2000s, Investor Immigration Programmes (IIP) have proliferated in a number of countries in order to attract investments from high-net-worth individuals in exchange for residency and even citizenship rights.3 The fore-going, taking into account that more than a quarter of the world’s countries offer specialized entry, settlement, and passport programmes for wealthy for-eigners, which is a profitable practice for States to obtain important econom-ic benefits and stimulate development.4However, IIPs have received substantial criticism, as they raise legitimate security, social, and, above all, legal concerns. This, considering that within the IIPs, there are programmes that effectively marketize citizenship because they offer the granting of their nationalities through the payment of a rather large sum of money without the fulfillment of any other significant require-ment.5 These modalities are called citizenship by investment programmes (CIP), commonly known as checkbook citizenship, purchased nationality, or golden passports. Prats defines them in the following way: “CIPs are laws that in a systematic way grant citizenship in exchange for economic transactions, which waives or significantly reduces requirements that other naturalization applicants need to fulfill, such as, but not exclusively, residence, language, or civic tests”.6