Understanding political opposition to European Union membership among member states and accession candidates has opened a flourishing field of empirical research over the past twenty-five years. From projects on citizen perspectives (Gabel, 1998) through comparative party taxonomies (Taggart and Szczerbiak, 2012), empirical studies draw primarily on data from the Eurobarometer series and national opinion surveys to explain EU opposition. Our work diverges from this discourse: Rather than developing a taxonomy of Euroskeptic parties in a comparative perspective or identifying contextual variables to explain sentiment trends, we offer a unified theoretical framework for domestic political party contention that illustrates how parties in both accession countries and member states may strategically position themselves vis-à-vis the government party to attract voters. We show that as the dimensionality of political contention increases through the addition of the European dimension, parties mobilize and optimize their position in the changing domestic arena.
