The European Commission, although still mainly portrayed as a technocratic, non-majoritarian institution, or as an agent of EU member governments, has become increasingly linked to the European Parliament (EP) through a range of semi-parliamentary measures in order to increase the executive’s legitimacy and accountability. In this article we argue that in addition to several highly visible and often treaty-based control instruments, an almost symbiotic, less visible, everyday relationship is observed between the two institutions. Based on an on-line questionnaire survey among EP staff as well as on minutes from EP committee meetings, this article examines the daily interaction taking place between the Commission and the EP, not least at the level of officials within the two institutions. Mutual interdependence in the legislative process may trigger daily interaction, however, the theoretical argument suggested by this article is that the everyday interaction is facilitated and reinforced under two particular conditions: (i) if the two institutions share similar organisational patterns, and (ii) if the two institutions share similar behavioural patterns. Three such patterns are emphasised: a sectoral, an ideological and a supranational pattern.
