ABSTRACT
This chapter discusses the merits of theorizing European Union (EU) counter-terrorism policy, reasons why it is important to approach this policy field from theoretically informed viewpoints. Exploring the external dimension of EU counter-terrorism brings new elements for the assessment of the main vectors of EU external actorness and to the understanding of EU foreign policy more broadly. The quick emergence of an autonomous European Union (EU) counter-terrorism policy in the aftermath of the terrorist attacks of 9/11 brought new challenges to some of the foundations of the Union. The promptness and the comprehensiveness of the EU's counter-terrorism policy action in the months following the terrorist attacks in New York and Washington indicate that something fundamental had changed beyond the mere existence of institutions and practices. The impact of the EU's constitutional foundations is observed in three separate phases during policy-making and implementation in counter-terrorism: aprioristic presence, legislative and executive presence, and ulterior supervision.
