As the above mentioned quotations underline, the current development of the European Union (EU) and the North Atlantic Treaty Organization (NATO) comprehensive approach is characterized by an open rivalry between both organizations. Both actors strive to be recognized as the favorite regional peacekeeper of the United Nations (UN). The EU points at its "uniqueness" as an actor gathering civilian and military capabilities whereas NATO emphasizes its highly efficient military might. The dynamics of EU/NATO relationship and the current competition between both organizations are closely linked to the evolution of the European security architecture. The end of the Cold War and the development of the European Security and Defence Policy (ESDP) have deeply affected the relations between EU and NATO.