Euroscepticism and the Dynamics of Polarisation in the European Parliament

The growing salience of Euroscepticism among both voters and parties has shifted the structure of political conflict in the European Parliament (EP) from traditional left-right competition towards an increasingly dominant pro-/anti-EU cleavage. Focusing on EU enlargement as a test case, we explore the emergence of this cleavage at different levels of MEPs’ legislative behaviour over the past two EP mandates (2009-2019). Drawing on two original datasets containing 1’250 MEP statements on enlargement in EP debates with their vote choice across 47 subsequent roll-call votes, we show a growing polarisation around enlargement issues: although discursive support for enlargement declines for all party groups, we observe a sorting of MEPs into two distinct camps that represent opposing views. Polarisation is even starker for roll-call votes. Finally, we find increasing coherence between discursive and voting behaviour for Eurosceptics that contrasts with an emerging discourse-vote choice gap for pro-European party groups. Our findings show that polarisation is primarily driven by soft Eurosceptics who become firmer in their rejection of further enlargement, ultimately leading to a consolidation of the pro-/anti-EU cleavage as main divide in the EP.