In the history of European integration, the late 1940s and the early 1950s were an era of experimentation. Federalist movements, activists and thinkers explored ways in which the unification of Europe could be achieved, yielding a wide array of blueprints and methods. There was considerable momentum behind the federalist ideal, with federalist movements amassing considerable support. The successive creation of new European organizations, moreover, fed into the hope that in a next step, governments could be convinced to join a political union. With Benelux, a regional customs union had already been founded during the war. The year 1948 saw the creation of a European military alliance through the Treaty of Brussels and the Organization for European Economic Cooperation (OEEC), charged with administering the Marshall Plan. The exploration of possibilities that characterized this era not only occurred among the federalist ranks, but at the offices of these new European organizations as well. Although these federalist movements and European organizations were entirely different environments, they were sites where new avenues of European integration were explored and experimented.

This chapter traces the different ideas of European unity that were considered in these postwar years, and what place a European assembly had in these imaginaries. It also analyses how the creation of the Consultative Assembly of the Council of Europe in 1949, as the first pan-European assembly, transformed these different imaginaries. In that sense, this chapter examines the intersection between unofficial and official forces labouring for European unity. The links between these two were quite strong – both in terms of people, but also in terms of ideas and practices. What characterized these parliamentary pioneers of European integration, especially compared to those in the more technical organizations, was a preoccupation with the democratic dimension of European unification.

During these early years, there were two opposing ways of thinking about the legitimation of European integration. The first revolved around technical decision-making by strong executive institutions; the second around democratic decision-making through a strong parliamentary legislative. These ideas, respectively underlying the repertoire of expertise and the constitutional repertoire, were rooted in longstanding political and intellectual traditions of state formation, international cooperation and technocratic internationalism (Kaiser & Schot 2014).