Internal security in the European Union has faced new dynamics as the perception of external threats changed drastically, into what has since then been called the global fight against terrorism. The beginning of the millennium brought a transformation in the understanding of security and required the EU to establish a comprehensive, cooperative and cohesive approach to the new challenges. The EU also needed to strengthen its relations with other international organizations in charge of security, such as NATO, and with countries of particular strategic significance, such as the USA. These imperatives were met by EU’s ambitions to emerge as a security actor on the world scene.