Enlargement is often described as the EU's most successful foreign policy. But it is much more than that. Enlargement does not only transform the countries that seek to join but it also changes the way the EU works.

The objective of joining the EU has helped the Central and East European countries to move from post-Communist upheaval to market economics and pluralist democracies in little more than a decade. Ten countries successfully joined the EU in May 2004, and Bulgaria and Romania followed in January 2007. However, the Union is showing signs of 'enlargement fatigue'. Many politicians worry that an ever larger Union will function badly, and that further widening will come at the expense of deepening. Workers in the EU fear the consequences of adding further low-cost economies to the Union’s deeply integrated single market. Future accessions would be very difficult unless public and political support for enlargement revives. The CER aims to debunk enlargement myths about Polish plumbers and institutional gridlock. We look at the merits, and challenges, of each individual applicant. And we point the way forward, through bold thinking on how an EU with up to 30 members could become strong, wealthy and effective.

Croatia's membership bid encounters little opposition, and the EU has accepted the other countries of the Western Balkans as potential candidates. Turkish accession negotiations remain more controversial, however. Although Turkey has formed a customs union with the EU since 1996, its full integration into the EU will be a big challenge: because of its size (with almost 70 million people and growing), its backward eastern regions, its still fragile political and legal system and, last but not least, widespread apprehension among West European voters. Since accession looks unlikely before 2015, both sides need to take a long-term view. Turkish membership would add a young and dynamic economy to a sluggish and ageing EU. It would help the EU to play a more constructive role in the volatile regions of the Middle East, Central Asia and the Black Sea. And it could contribute to the energy security of the whole of Europe. For Turkey, EU accession provides a solid anchor for political stability and economic modernisation.

The CER's Turkey programme provides balanced analysis of, and fresh policy ideas for, Turkey's complex accession process. We bring together politicians, academics, businesspeople and journalists to encourage open and informed debates about possible stumbling blocs. At our annual Bosphorus conference in Istanbul (which we organise with the British Council and the Tesev think-tank) we have welcomed Ali Babacan, Olli Rehn, Peter Mandelson, Mehmet Simsek, Abdullah Gül, Geoff Hoon, Carl Bildt, Cathy Ashton, Hilmi Guler, Frits Bolkestein and many others.