Does the European Union transform the institution of diplomacy?

Diplomacy as a framework of principles, rules and organized patterns of behaviour regulating interstate relations in the Westphalian system of states is challenged by the process of European integration. This article conceptualizes diplomacy and its change using two new institutionalist perspectives that provide complementary insights into the nature of diplomacy as an institution. These are then applied to the study of diplomacy in the EU. The process of European integration is shown as challenging the institution of diplomacy at three levels: (a) the intra-European bilateral relations; (b) the multilateral setting of the Council; and (c) the emerging capacity of the EU to conduct external diplomatic relations with third states. The article assesses change in and of diplomacy at these levels.