Divided We Stand: Intra-Party Dissent over European Integration

European integration is one of the single most divisive issues within European political parties.  The past two decades have shifted the EU from the economic realm into the political realm and have galvanized political systems. Despite its substantive importance, the theme of intra-party dissent has managed to skirt scholarly attention. Studies have typically focused on national party positioning on EU issues and on conflicts among political parties, relegating dissent within parties to the backbenches of academia. What are the nature, causes, and consequences of intra-party dissent on European issues?  How can we explain the variability of intra-party dissent across parties?  This paper refines work on party positioning by evaluating four sets of hypotheses regarding intra-party dissent: 1) internal divisions may depend on the institutional environment, namely the type of electoral system in which a party competes; 2) rifts within parties may be a consequence of the strategic actions of political parties, suggesting that mainstream and peripheral parties may differ in their levels of dissent; 3) shifts in a party’s position on an issue may engender conflict; 4) the ability of political parties to effectively incorporate new issues into their existing ideologies hinges upon the extent to which the issue activates pre-existing tensions. Using expert survey data from 1984-2014, I demonstrate that type of electoral system, changes in party position on the EU, and a party’s historical legacies and programmatic commits all have bearing on the degree of dissent that a political party is likely to experience.