Consistency and diversity? The EU's rotating trio Council Presidency after the Lisbon Treaty

The Lisbon Treaty introduced significant changes to the Presidency of the Council of the European Union (EU). The new Treaty combines a permanent chair with the principle of rotation based on three member states collaborating during an 18-month period, without specifying the responsibilities of trio groups. This left wide scope for the first post-Lisbon trio to establish new working mechanisms. By discussing the joint Presidency of Spain, Belgium and Hungary, this article interprets the trio model and its combination with the permanent chair model as an attempt to re-adjust the balance between consistency and diversity. Rotation remains a key instrument for ensuring the representation of the diversity of member states in an enlarged Union. At the same time, the EU's ever more complex policy agenda and a greater need for collective leadership motivate the search for new forms of co-operation to enhance policy consistency over consecutive Presidency terms.