| How resistant are political parties and party systems in developed democracies to processes of economic and political integration that cross nation-state borders? Europe, the most integrated and democratised part of the world, is among the suitable arenas in which we may find the answer. This project considers the effect that European integration has on party systems in the EU member states, by considering the two spheres that constitute a party system---the relationships between parties and their voters on the one hand, and the context and conditions of interaction among the political parties on the other.;I test the hypothesis of the EU's significant impact on key party system elements, its size (number of relevant parties), and its ideological breadth (polarisation). Further, I test the claim that the interactions parties have with their voters are at the root of any change in these key party system parameters. In a cross-national study, I find that party system polarisation on the economic left-right dimension has been reduced in the countries that are part of the Economic and Monetary Union, as a result of the shrinking of viable policy options that prospective governments are able to choose from. The effective number of parties increases with the intensification of European integration overall, an apparent result of the potential of European integration to spark challenges from outside the economic left-right dimension.;While the average effect of Europe on individual elements of party systems is significant, each country is found to exhibit its own party system constellation, depending on history and context. The case studies (UK, Portugal, and Italy) demonstrate how these broad Europe-wide processes bring about different political outcomes in the EU member states. In the case studies, I explore the voters' engagement with the issue of European integration, and the parties' responses to the voters' concerns. I utilise the available data from election studies, as well as interviews I have conducted with key party officials and strategists in the three countries, finding that party systems do change as a result of European integration, but this impact is by no means creating convergence across countries. |
