Who Teams up with the European Parliament? Examining Multilevel Party Cooperation in the European Union

Abstract As in nearly all European Union (EU) policy areas, scholars have turned to analysing the role of national parliaments, in addition to that of the European Parliament (EP), in trade politics. Yet, there is limited understanding of how the parliamentarians at the two levels interact. This article fills the gap by conceptualizing these interactions as a continuum ranging between cooperation, coexistence and competition. We use this continuum to explore multilevel party interactions in EU trade talks and show how cooperation compels politicization – national parliamentarians mainly interact with their European colleagues in salient matters. However, we argue that the impact of politicization on multilevel relations between parliamentarians in the EP and national parliaments is conditioned by party-level factors. Hence, we account for how and why politicization triggers multilevel party cooperation across parliaments in the EU through ideological orientation, government position and policy preferences and show how this takes place in the case of trade