Eurosceptic Challenger Parties and Political Opposition in European Union Politics: Part of the Problem or Part of the Solution?

Despite extensive research on Eurosceptic challenger parties, our knowledge of their influence on political opposition has so far been sparse. In this article we make an in‐depth assessment of parliamentary EU opposition, based on 4,264 statements made by national parliamentarians in the European Affairs Committees (EACs) of Denmark and Sweden. Our analysis shows that the presence of Eurosceptic challenger parties in the national parliamentary arena impacts patterns and practices of EU opposition significantly. A greater presence of ‘hard’ Eurosceptic parties in parliament is associated with more opposition in EU politics. These parties deliver a vast majority of the polity‐oriented opposition towards the EU and present more policy alternatives than mainstream parties. The findings presented have implications for our understanding of national parliamentary EU opposition as well as for the assessment of the impact of Eurosceptic challenger parties on the process of European integration.