Laying Sound Foundations for Social Identity Theory‐Inspired European Union Attitude Research: Beyond Attachment and Deeply Rooted Identities

There is a growing body of literature examining the influence of social identification on E uropean U nion ( EU ) attitudes. Broadly speaking, this literature can be divided into two strands. One strand examines the way social identity affects support for EU integration quantitatively, using opinion poll data. The other draws (often loosely) on social constructivism, using qualitative research methods. S ocial I dentity T heory ( SIT ) is increasingly invoked in both these literatures and this development is to be welcomed. However, so far engagement with SIT has been rather tentative, drawing largely on theoretically impoverished versions of SIT. It is argued in this article that this practice has resulted in SIT 's theoretical potential being underutilized. At other times, this has resulted in theoretical confusion because SIT explanations are being used alongside other theories whose premises clash with core SIT assumptions. We conclude that more in‐depth engagement with SIT 's basic and core tenets will enable quantitative EU identity researchers to move beyond ‘attachment’ to territorial identities, and allow qualitative EU identity researchers to move beyond ‘shared history’, ‘deeply rooted identities’ and ‘resonance’.