Fairness for Outsiders: Negative Externalities Reduce Public Support for Differentiated Integration in the EU

Differentiated integration (DI) is often portrayed as a solution to gridlock in the European Union (EU). However, DI may create externalities for those EU member states who, for capacity or sovereignty reasons, do not join a common policy. Therefore, the assessment of DI externalities has been proposed as a standard for the normative evaluation of DI (Lord 2015). This article investigates if citizens consider external effects when forming their opinion on DI initiatives. Results from a factorial survey experiment in eight EU countries show that negative externalities have a large statistically significant effect, reducing public support for DI. In contrast, positive externalities have no statistically significant impact on public support. The analysis shows that citizens are not exclusively focused on the affectedness of their home country when evaluating an international agreement such as the decision to opt for DI in the EU. Rather they value the fairness of the decision for all EU members states.