What are the factors that explain the politicisation of the European Union in the European Parliament?

It is often claimed that, since the signing of the Maastricht Treaty, the European Union (EU) and its policies have become increasingly politicised. As issues of European integration become more salient and contested, both in public opinion and in inter-party competition, politicisation takes root in the various political and public spheres of the member-states, often stressing the institutional capacity of the EU at particular critical junctures. However, the unfolding of such dynamics of contestation remains understudied at the EU-level. The present research seeks to address this research gap. This paper examines how the dynamics of EU politicisation are translated from the national sphere of politics to the EU’s institutions themselves, specifically in its only directly elected legislative institution - the European Parliament (EP). By applying automated text analysis techniques, specifically Wordfish, to analyse the debates in the EP plenary between the 5th and 7th terms (1999-2014), the research assesses the factors that explain the politicisation of the EU in the EP during a particularly challenging period in the history of European integration when the Union underwent the establishment of the single currency, the enlargement towards eastern Europe, and the crisis of the Eurozone. The analysis shows that, as far as the internal factors to political parties are concerned, party ideology and party type are a significant predictor of EU politicisation in the EP. Furthermore, regarding the external factors to parties, the research demonstrates that the transfer of political authority from the member state to the supranational level is less relevant than the degree of institutional misfit between the two levels in explaining the politicisation of the EU in parties’ EP speeches.