The aim of this paper is exploring in how far European integration changed the say of opposition parties and individual deputies within the national parliaments of the Benelux countries. Legislatures have adapted internal procedures and structures to European integration demands in order to account for increased EU legislative activity and the information advantage ministers enjoy in the Council deliberations. Some authors argue that due to European integration legislators nonetheless lost stance over their respective executives, leading to a de-parliamentarization of politics (Maurer and Wessels 2001). However, we argue that this de-parliamentarization thesis needs fine-tuning: Party politics are determining the way how legislatures control governments in EU affairs. Party politics has become more relevant as Europeanization became more contested in the parliamentary arena and in other venues of attention. On the one hand, European integration further increases the fusion of executives and legislatures, as cooperation with the government is necessary in order to carry out effective scrutiny in EU matters (Börzel & Sprungk 2007). On the other hand, parliaments have to increase scrutiny as the uncertainty at EU level increased: The more areas are decided at EU level, and the more actors are involved, the more uncertain is the outcome of negotiations for member states in general, for governments as well as for parliaments. Institutional innovation within parliaments not only served the national interest in general, but opposition parties more particularly, as they were largely excluded from the game played at European level.
