Ramses A. Wessel is Professor of the Law of the EU and other International Organisations at the University of Twente, Enschede, the Netherlands and a member of the governing board of the Centre for the Law of EU External Relations (CLEER). Steven Blockmans, a former Head of Research at the T.M.C. Asser Institute in The Hague, the Netherlands, is a Senior Research Fellow and the Head of the EU Foreign Policy Unit, Centre for European Policy Studies in Brussels, Belgium; Professor of EU External Relations Law and Governance at the University of Amsterdam, the Netherlands; Visiting Professor at the University of Leuven, Belgium and a member of the governing board of CLEER.