The adaptation of radical left and radical right Eurosceptic parties in government: not two sides of the same coin

The participation of radical parties in government has long been a subject of debate. Research shows that Euroscepticism has been an effective electoral strategy for radical right parties (RRPs) and radical left parties (RLPs), enabling them to attract votes and secure government positions. However, how do these party families adjust their positions on European integration once in government? This study examines two key dimensions, Euroscepticism and government participation, through a large-scale quantitative study using the Chapel Hill Expert Survey (CHES). Given the multifaceted nature of Euroscepticism, the analysis explores whether governing affects RRPs and RLPs differently. The findings reveal that while RLPs moderate their Euroscepticism in power, RRPs remain ideologically rigid, yet display notable variability and heterogeneity within their party family. These results challenge the uniform application of the ‘inclusion-moderation’ thesis and contribute to debates on the persistence of Euroscepticism in government and its broader implications for European integration.