Differentiated integration (DI) has received significant scholarly attention. However, little consideration has been given to whether political actors find it acceptable. Drawing on 35 semi-structured interviews with party actors from seven member states and situated across the political spectrum, we show these actors to be divided in their assessment of DI. While a small majority thought it could facilitate integration and protect diversity, others worried about its negative implications for the EU’s unity and principles. Respondents’ national belonging and experience of DI proved important in forming their views, with interviewees from richer and strongly integrated MS tending to be more favourable towards DI than those from poorer and less integrated ones. These findings suggest that DI will not be equally welcomed by all MS, and may in some circumstances prove more contentious than an undifferentiated process of integration.
