This paper identifies and explains variation in opinion congruence between parties and voters on the left-right and pro-anti-EU dimensions in EU elections over time. Until Maastricht, there is no clear pattern of
congruence. Our results show that from Maastricht and until the mid-2000s Eurosceptic parties are worse at representing their voters on the left-right dimension but better on the EU dimension than mainstream parties. In the 2009 elections we find convergence on both dimensions. We anticipate this trend to intensify in the 2014 elections as the financial crisis has increased the salience of the growth vs austerity debate. We put forward hypotheses on the system and party level, which are tested in a combined dataset for seven EU elections (1979-2009). Our results suggest that four main effects explain this variation, including the polarization of public opinion towards the EU, party system fragmentation, GDP growth and the unemployment rate.
