The main thesis of the paper is rooted in the view that the activities of the European Union are based on two interconnected phenomena: Member States play a leading role in the EU institutional system but at the same time they are being Europeanised. Special attention will be paid to the position of newcomers (EU-12). They have a very moderate impact on creation of the most important EU decisions. The following elements will be discussed: the position of the Member State in the EU decision making system (intergovernmental view); the formal position of twelve new Member States in EU institutions according to the Nice system and its limitations in the Lisbon system; selected challenges connected with Europeanisation (decision-making challenge, post-conditionality challenge, compliance challenge, primacy challenge); and an evaluation of in casu connections between the real position of the EU-12 Member States in the EU system and their Europeanisation.
