Within sovereign states citizenship is arguably the most important political marker of
in- and outsiders. As a result, questions about who gets to reap the benefits of citizenship
often result in distributional conflict. This conflict becomes inflamed when a country goes
through a period of significant inward migration. Given that citizenship is so important
and so contentious, from where do the rules governing its acquisition come? Our starting
point is the acknowledgment that migrants are mobile labor. From this perspective, countries in which elites benefit from an increased supply of productive labor—that is, those
with high land/labor ratios—will be more likely to adopt policies that attract migrants,
such as easier naturalization rules, including birthright citizenship. We illustrate the plausibility of our argument with some statistical evidence and suggest some avenues to further explore this crucial question.

Melle Scholten and David Leblang, “Land/Labor Ratios, Citizenship, and Migrants: Exploring the Hidden Links in the Political Economy of Immigration Regimes“, World Politics, 2023.