South European party systems have shown a remarkable stability in terms of party format and dynamics of party competition. Even after the emergence of the economic and financial crisis, only Greece has experienced significant changes, while the remaining countries of the region have been characterized by a high degree of resilience of their party systems. What kind of factors may account for this pattern? How can we explain the different trajectories undergone by South European countries after the 2008-2012 economic crisis? We argue in this paper that party system change is mainly driven by the rise of a new cleavage based on the politicization of the European integration issue. The poor economic performance of the incumbents has an important impact on electoral outcomes, but it is not a sufficient condition to foster significant changes in South European party systems. By looking at intra-party conflicts and change in public opinion, we examine to what extent a new divisive issue, based on European integration, has affected the relative strength of party actors and their interaction. In order to show the importance of the European cleavage, we will consider internal splits, the change in the programmatic orientations of new parties and the main issues of dissent during recent electoral campaigns. As for the analysis of the resilience of South European party systems, we will distinguish between party system change in the electoral arena, on the one hand, and the institutional-governmental level, on the other. The hypothesis is that there are no governmental alternatives to the main parties. Radical and extreme parties do not offer a viable alternative, thus most of the electorate has to choice between the main parties.
