Chapter 2 by Petr Kaniok deals with the involvement of national parliaments in the political system of the European Union (EU). More specifically, the chapter focuses on the analysis of the ability of the national parliaments to establish a collective institution in order to carry out tasks which were assigned them by the Lisbon Treaty. It, inter alia, empowered parliaments with specific rights to control proposals of EU legislation, turning them into a new collective actor of the EU political system. Thus, national parliaments have since 2009 been de facto collective institutions involved in the EU decision-making process. The main contribution of this new institution should have been and should be to deliver more democracy and more legitimacy for the EU. The establishment of this new actorness can be seen as an innovative effort to decrease the democratic deficit in the EU. At the same time, even when the Lisbon Treaty was adopted it was clear that if national parliaments function in this way, they have to overcome huge diversity in various aspects – for example their size, positions within domestic political systems, administrative capacity, etc. –in order to create an effective collective institution. Here, the question is how they have so far been successful and how the national parliaments’ collective actorness has been working. The chapter carries out such an analysis. It particularly analyses the collective actorness of EU national parliaments in the period 2010–14, using their participation in the so-called early warning system in order to find out whether parliaments succeeded in establishing an effective collective institution, which factors are shaping it and what their influence means for national parliaments’ contribution to EU democracy and legitimacy. As its main finding, the analysis reveals that national parliaments failed in the period 2010–14 to establish an effective collective institution. This failure substantially affected parliaments’ ability to deliver more democracy to the EU political system and is explained by huge institutional variety across chambers and parliaments. Moreover, the analysis finds that if cooperation takes place, it is particularly shaped by technocratic and expertise factors limiting the involvement of political actors.