His research interests include European integration, foreign policy, political parties, and transnationalism. In particular, he has published widely on various aspects of transnational party cooperation within and throughout the European Union. Recent publications include “Party Politics in the European Council”, with Jonas Tallberg (Journal of European Public Policy, Vol. 15:8); and “The Emergence of Political Parties at European Level: Integration Unaccomplished”, in How Unified Is the European Union? European Integration Between Visions and Popular Legitimacy, edited by Sverker Gustavsson, Lars Oxelheim & Lars Pehrson (Springer, 2009). In 1999, he was a visiting senior fellow at the Center for European Integration Studies in Bonn. From 2002 to 2005 he was a member of the steering committee of the Center for German Studies at Södertörn University.