Inter(b)locking Institutions: The European Union, the Council of Europe, and Human Rights Protection in Europe.

This article seeks to explain variance in the relationships between international organisations. Empirically, the article examines the degree of co-operation and conflict in the interaction between the European Union (EU) and the Council of Europe (CoE) in the field of human rights promotion and protection in Europe. Drawing on organisation theory and International Relations (IR) literature on institutional interaction, the article argues that, depending on their intensity, challenges to organisations' interests lead to different types of institutional interaction (ranging from disruptive to synergistic). The theoretical propositions are tested in three case studies on the interaction between the CoE and the EU concerning the establishment of the European Union Agency for Fundamental Rights, the investigation of CIA activities in Europe and the conducting of 'joint programmes'. The case studies show how challenges to the CoE's organisational interests by the EU triggered inter-organisational conflict, whereas the lack of such challenges led to a mutually beneficial interaction. [ABSTRACT FROM AUTHOR]