Identity and nationalism do affect attitudes toward the EU: political-science research finds that national identity can reduce support for integration and put the project under pressure. But the same literature also says national identity is not inherently a barrier and can coexist with EU support. Official EU histories show the European project has in fact produced durable institutions, the single market, the euro, border-free travel, and decades of peace/cooperation, and Eurobarometer data around 2011-2012 show many Europeans felt both national and European identities. So tribalism is a plausible brake on integration, but the evidence does not support the stronger claim that the European project cannot work because humans are tribal. (journals.sagepub.com) Sources: European Union, “History of the EU” and “EU motto”; Council of the European Union, “The Schuman Declaration”; Aichholzer, Kritzinger & Plescia, “National identity profiles and support for the European Union” (SAGE); Foster & Frieden, “Economic determinants of public support for European integration, 1995–2018” (SAGE); Eurobarometer 77.4 “Focus on euro/non-euro identity” (European Parliament).