Zero-Sum or Reinforcing? The Long-Term Dynamics of European and National Identification

While scholarship broadly agrees that European and national identities can coexist, systematic longitudinal evidence on their dynamic relationship remains limited. This paper examines how European and national identification have evolved in relation to one another from 1970 to 2023 across 28 countries, drawing on over 3 million survey observations. Using a Bayesian modeling approach, the analysis addresses whether these identities develop as zero-sum competitors or can strengthen simultaneously. The paper traces how the relationship between multi-level identity structures has shifted through successive integration milestones and crises, from Maastricht to Brexit, and examines whether this relationship varies systematically across member states. By providing comprehensive longitudinal analysis across five decades, this research advances understanding of how citizens negotiate multiple group memberships in complex polities. These insights extend beyond Europe to multilevel governance systems where managing multiple identities remains central to political legitimacy and citizen engagement.