The paper grasps the phenomenon of institutionalising the EU´s cooperation with Ukraine, Moldova, the RF and even with Belarus, which started with the entry into force of the Partnership and Cooperation Agreement (PCA) in 1997 with the Russian Federation (RF) and in 1998 with Moldova and Ukraine up to the current negotiations with the respective countries on an enhanced association agreement. The current institutional framework got revitalised by several initiatives as the European Neighbourhood Policy (ENP), the “Four Common Spaces” with the RF and the Eastern Partnership (EaP). Further, this paper emphasizes the importance of institutionalising the cooperation by introducing task-specific policy networks to guarantee a harmonisation and internalisation of norms, rules and objectives in the long-run (e.g. Lavenex 2008 and Schimmelfennig/ Sedelmeier 2008). Apart from conventional foreign policy in the tradition of tit-for-tat, several non-hierarchic modes and strategies find their way in the EU´s external policy coordination to solve collective problems (e.g. Lavenex 2008; Weber/ Smith/ Braun 2008; Meloni 2007; Schimmelfennig/ Sedelmeier 2005). But, as the cooperation is merely of voluntarily basis, the paper raises the questions: why third countries agree on institutionalising their cooperation and how these can be as efficient as the ´accession conditionality` in resulting legal approximation between the EU and neighbouring countries? Therefore, the paper stresses the importance of several conditions, which determine the extent and the efficacy of institutional settings of Interstate Cooperation. This may help to figure out limits and possibilities in integrating third countries into EU policies without offering EU membership.
