Governing global migration is one of the most pressing issues of our time. With more than 250 million international immigrants, the question of how citizenship should be distributed has become a controversial issue, morally and politically. Traditionally, international law has not regulated nationality law; naturalization requirements remain the last stronghold of national sovereignty. This project advances the establishment of a new subfield in public international law—International Citizenship Law (ICIL)—which would govern nationality law. It asks a critical and timely question: What should be the international norms and structure in setting up requirements for naturalization and, more broadly, for granting citizenship?

In order to address this question, the project has five objectives: [1] to investigate the history of naturalization and what it can teach us about 21st-century challenges; [2] to identify the recent legal developments and establish the most up-to-date legal standards in the field of naturalization law that, taken together, may form the basis for ICIL; [3] to set out the theoretical foundations and the justifications for the establishment of ICIL; [4] to analyze the normative and structural implications derived from an-ICIL approach for future citizenship policy development; and [5] to explore the interrelationship between ICIL, global migration, and constitutional identity.

In essence, the project seeks to formulate international standards by which states can admit migrants without fundamentally changing their cultural heritage and slipping into extreme nationalism. The outcome can serve as a basis for a future reform in international law, EU law, and national legal systems.