1 TO BE or NOT TO BE with TURKEY; DECEMBER 2004 BLUES FOR THE EU The decision of the European Council in December 2004 on whether to start accession negotiations with Turkey will mark a historic turning point in Turkey-EU relations. Both sides are now standing at a crossroads contemplating whether to take advantage of the probably benefits of Turkey’s membership or bear the costs of its exclusion from the Union. This paper will explore the potential implications of integrating Turkey into the EU by charting out a multi-level, multi-disciplinary cost/benefit analysis for both sides. In this context, it will try to sort out whether enlarging to include Turkey is really something indispensable for both or either side. Mustafa Aydın ∗ and Sinem Akgül Açıkmeşe ** ∗ Mustafa Aydın is an associate professor of International Relations at the Faculty of Political Sciences, Ankara University. ** Sinem Akgül Açıkmeşe is a PhD candidate and research assistant at the Institute of Social Sciences, Ankara University, Turkey.