2
How can one explain public opinion on European integration? The question is as old as the
European Union, and it has been the subject of some one hundred articles, yet there is no
scholarly consensus on the answer. One line of explanation builds on trade theory to theorize a
calculus of economic costs and benefits. The presumption is that citizens evaluate the economic
consequences of European integration for themselves and for the groups of which they are part,
and that such consequences drive their attitudes. A second explanation draws on cognitive and
social psychology to assess how individuals use political cues—grounded in ideology or in elite
communication—as a guide to new and complex issues. A third line of explanation draws on
the psychology of group membership to consider how territorial identities including, above all,
national identities, constrain support for European integration.
Each of these conceives of the object of attitude formation—the European Union—
differently. The political-economic approach views the European Union as a regime that
facilitates economic exchange, with profound distributional consequences arising among
individuals from differences in asset mobility and among countries from varieties of capitalism.
The political cue approach regards the European Union as an extension of domestic politics,
and infers that public attitudes are guided by domestic ideology and domestic political
organizations. The identity approach conceives of the European Union as a polity overarching
established territorial communities, and considers how public opinion is constrained by
citizens’ conceptions of their identities.
We find empirical support for each explanation, but we conclude that the latter is by far
the most potent. Conceptions of in-groups and out-groups are immensely powerful in
explaining public opinion on European integration. Political cues and economic evaluation of
costs and benefits have significant, but much weaker, effects. We conclude that European
integration provokes emotional responses that express communal identities. We generalize
Convention