The Lisbon Treaty by taking up a decision adopted during the Convention on the Future of Europe has finally attributed the formal rank of Institution to the European Council. Although the European Council is already for a long time considered as the top of the EU system, this “consecration” may conduct to changes in the practices observed in the EU Council. Following a long established practice, the Lisbon Treaty explicitly stipulates that “decisions of the European Council shall be taken by consensus”, introducing then the consensus officially as an EU Decision-Making method. This method allows decision-makers to “avoids the public disclosure of the member states preferences and prevents member states from being publicly outvoted” (Novak, 2007). If the enlargement has not affected this practice in the EU Council (Heisenberg in McNamara and Meunier, 2007), the small evolutions associated to the Lisbon Treaty might on the contrary conduct to substantial transfer of practices. This paper will focus on the interactions between the European Council and the Council of the European Union through the attitudes of the actors evolving in both of these institutions, including the officials from the General Secretariat of the Council, to evaluate in what extent practices of consensus are being transferred.
