Which Affects the Other? Investigating the Relationship between National Identities and Attitudes in a Multilevel State

National identities are often important in multilevel states like the United Kingdom, and researchers regularly use them to understand political attitudes and behavior. However, quantitative researchers tend to treat these identities as static and causally prior to political attitudes, without testing these assumptions. Consequently, I address three questions: Are there relationships between national identities and political attitudes? Do they change over time? If so, why? Using data from the British Election Study Internet Panel (2014-2023), I examine the relationship between state/sub-state identities and three political attitudes (redistribution, immigration, and Europe) in England, Scotland, and Wales through a series of random intercept cross-lagged panel models. Overall, the connection between national identities and attitudes is often reciprocal – either can affect the other, depending on the context. These results suggest that quantitative researchers should reconsider how they conceptualize and operationalize national identities and their relationships with political attitudes in multilevel states.