This thesis aims to assess, with the help of the concept of security culture, the impact that Turkish membership will have on the European Union’s foreign and security policies. It argues that any analysis of the impact of Turkey on the EU’s role as an international actor needs to take into account existing divisions within Europe and within Turkey in terms of security culture. Neither the EU nor Turkey is a monolithic actor when it comes to security understandings and preferences. This thesis argues that, due to the existence of a plurality of security cultures within Europe, EU member states can be grouped according to those supporting the project of a Global Power Europe, Humanitarian Power Europe and Minimum Power Europe. For its part, Turkey has two security cultures, which I have called “Republican” and “neo- Ottomanist”. This thesis argues that an assessment of Turkey’s impact on the role of the EU in the world stage must take into account the three existing normative approaches for the future of the EU (Global, Humanitarian, and Minimum Power Europe) and the characteristics of Turkey’s Republican and Neo-Ottomanist security cultures. After locating where Turkey’s security cultures sit in the broader picture of European security landscape, this thesis concludes that Turkish membership is unlikely to significantly alter the EU’s role in the international system. With or without Turkey, the EU will probably continue to resemble a Humanitarian Power in the world stage. This finding makes an important contribution to the literature by challenging the binary logic that pervades the discussion about Turkish membership in the areas of foreign and security policies and has important implications for EU policy towards Turkey.

When Turkey became a candidate of the EU in 1999 it had been a problematic applicant for forty years due to residual unpopularity with several member states for cultural, economic, security and normative reasons. However, the Helsinki European Council heralded a change of fortunes for Ankara and by 2005 accession negotiations had opened. This happened in spite of Turkey remaining an unpopular candidate with some member states. Moreover, since 2005, Turkey s standing within the EU has returned to a position akin to its pre-1999 stasis. This thesis thus asks: why did Turkey make such progress between 1999 and 2004/5? What was the specific configuration of structures, processes and actions that enabled that to happen then but not before or after? The thesis approaches this puzzle using a stretched eclectic version of Historical Institutionalism which can incorporate the effects of both structure and agency. In this way it can include the influence of wider structural factors, such as CEEC enlargement, Cyprus and ESDP as well as the agency of Turkey s advocates within the EU. It is a detailed qualitative process-tracing study which uses semi-structured interviews and documentary evidence to make a case for a given explanation. It concludes that a path dependent process, influenced by both structure and agency, can be traced from the Helsinki European Council to that in Brussels five years later which rhetorically entrapped the member states into agreeing to open accession negotiations in spite of Turkey s underlying unpopularity. By adopting this framework for analysis, the thesis makes a contribution to the literature on the Turkey-EU accession process by viewing the time period as a whole and taking a temporal rather than a snapshot approach. In so doing it is possible to explain why and how Turkey was able to make such progress between 1999 and 2004. It is also valuable in the study of present Turkey-EU relations as the ultimate conclusion has to be that there was a unique window of opportunity for both Turkey and the EU during this time and the window may now have closed.