When does national identity become exclusionary? A multilevel analysis of the conditional effect of ethnic diversity

Abstract Why is national identity associated with anti-immigrant attitudes in some countries but not others? Existing research documents cross-national heterogeneity but offers limited insight into the conditions under which national identity becomes exclusionary. Building on Social Identity Theory, I argue that ethnic diversity conditions this relationship by shaping how clearly the national prototype is ethnically defined. In less diverse countries, a clearer prototype makes citizens and immigrants more readily comparable, strengthening the exclusionary implications of national identity. By contrast, in more diverse countries, a less ethnically determinate prototype reduces comparability and weakens this link. Multilevel models using the 2003 and 2013 ISSP National Identity modules show that national identity is, on average, positively associated with anti-immigrant attitudes, but that this association weakens significantly as ethnic diversity increases and becomes statistically indistinguishable from zero at high levels of diversity. The pattern remains substantively unchanged when using alternative measures of anti-immigrant attitudes, national identity, and ethnic diversity and after accounting for rival contextual explanations. I also use Eurobarometer data to probe the proposed process, treating perceived national commonality as an indirect indicator of national prototype clarity. Greater ethnic diversity is weakly associated with lower perceived commonality, and the positive association between national identity and negative attitudes toward immigration weakens as perceived commonality declines. These findings highlight the importance of ethnic diversity for understanding the exclusionary potential of national identity.