How do prospects of EU membership influence support for secession? A survey experiment in Catalonia and Scotland

The past years have been eventful for secessionist movements in Europe and in particular in Scotland and Catalonia. Supporters and opponents of secession of both stateless nations considered their prospects for future EU membership as an important part of the campaigns leading to the referendums. The article's aim is to explore whether international factors influence domestic support for secession. In order to answer this puzzle, an on-line survey experiment (n = 2408) was carried out in Catalonia and Scotland in which respondents were confronted with different scenarios concerning the EU membership of their hypothetical new state (inclusion or exclusion). Contrary to the general perception, the prospects of EU membership had only a limited effect on support for the creation of a sovereign state. Moreover, it was found that the impact was strongly mediated by the participants' previous degree of nationalism and their attitudes with respect to the EU.