Genealogy and Law Without Borders: Comparative Nationality Regimes and the Global Circulation of Descent

Citizenship is not only a legal status but also a form of recognition. Every state defines who belongs by tracing lines of descent, yet the way ancestry is proven differs widely. This study compares nationality laws in Europe, Africa, and North America to show how evidence shapes access to citizenship. It asks what kinds of proof states require and what happens when those forms of proof are missing. The analysis draws on nationality laws, constitutional texts, case decisions, and administrative practice. The findings show that Europe relies on documents and registration systems that treat records as truth, while African states face gaps in documentation that leave many citizens unrecognised. In North America, technology and DNA testing have made biology a new measure of belonging. Across these regions, the law of descent has become a law of evidence. Documents and DNA dominate, while oral and community genealogy have lost authority. These evidentiary habits travel across borders, shaping how migrants and diasporas prove identity in a world that equates paperwork with legitimacy. The study concludes that certainty and fairness can exist together if states accept multiple paths to proof. When documents, sworn statements, and community testimony are combined, the law can recognise descent without excluding those who lack official records. Belonging should rest not only on what is written or tested but also on what is known and trusted.