My dissertation explores the impact of international border changes on the formation and transformation of national identities. It proposes a theory that emphasizes how individuals in newly transferred territories are incentivized to assimilate into the core nation of the new state. Modern territorial states often create status hierarchies among ethnic groups, with core nations enjoying higher status and benefits. Consequently, individuals adopt cultural and linguistic traits associated with the dominant national identity to enhance opportunities and reduce discrimination. As state borders shift, territories with ethnically mixed populations face new incentives to display different ethnonational traits, fostering assimilation into the new state’s core group.
The empirical analysis covers Europe between 1816 and 1938, employing quasi-experimental methods to estimate the effects of border changes on national identities. Using novel datasets of historical book publications and of nationalist mobilization, the dissertation demonstrates that new borders create divergence in ethnonational identities, while removed borders lead to convergence. Specifically, elites in transferred territories quickly adapt their publication languages to align with the new state’s core identity. The case study of Alsace-Lorraine further illustrates that assimilation efforts are long-lasting but contingent on continued territorial control. The findings challenge the conflict literature’s assumption that political violence hardens identities, suggesting instead that border changes can promote assimilation through self-interested behavior by local elites.
Overall, the dissertation contributes to understanding the role of international borders in national identity formation, highlighting how border changes influence ethnonational identities and suggesting implications for policy and future research.