20 Years Eastern Enlargement of the European Union

Taking stock and looking ahead

In this edition of our full-day conference in cooperation with the Andrássy Universität Budapest, we want to take stock of the achievements of 20 years of EU membership of the Central and Eastern European countries, give an outlook on the Hungarian EU Council Presidency, and discuss the various challenges for the EU and the Central and Eastern European region.



Link for registration of in-person attendance in Budapest HERE.

Link for registration of online attendance in our Zoom webinar HERE.


The largest enlargement of the European Union, in terms of number of states and population, took place 20 years ago on 1 May 2004.

The simultaneous accession of the so called "A10" included Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, and Slovenia. Seven of these were part of the former Eastern Bloc, of which three were from the former Soviet Union and four were and still are member states of the Visegrád-4.  Slovenia was one of the former republics of non-aligned Yugoslavia and the remaining two were Mediterranean island countries.

Part of the same wave of enlargement was the accession of Bulgaria and Romania in 2007, who were unable to join in 2004, but, according to the Commission, constitute part of the fifth enlargement. The eight CEE countries were referred to as A8, because of their relatively similar ex-Eastern bloc background, per capita income level, Human Development Index level, and most of all the geographical location in mainland Europe. Another reason for grouping the A8 countries was an expectation that they would be the origin for a new wave of increased migration to wealthier European countries. They initially proved to be the origin of a new wave of migration, with many citizens moving from these countries to other states within the EU, later giving a way to newer EU members, like Romania, Bulgaria, and increasing migration from the southern Europe struck by the global financial crisis. It took the EU a long time "digesting" the enlargement. The influx of new members had effectively put an end to the Franco-German engine of the EU, as its relatively newer members, Poland, and Sweden, set the policy agenda, for example the Eastern Partnership. Despite fears of paralysis, the decision-making process had not been hampered by the new membership and if anything, the legislative output of the institutions had increased, however justice and home affairs (which operates by unanimity) had suffered. In 2009 the Commission saw the enlargement as a success but thought that until the enlargement was fully accepted by the public, future enlargements would be slow in coming.

The internal impact has also been relevant. The arrival of additional members has put additional stress on the governance of the Institutions, and significantly increased overheads (for example, through the multiplication of official languages). Before the 2004 enlargement, the EU had twelve treaty languages, due to the 2004 enlargement, nine new official languages were added.

A 2021 study in the Journal of Political Economy found that the 2004 enlargement had aggregate beneficial economic effects on all groups in both the old and new member states. The largest winners were the new member states, in particular unskilled labour in the new member states.

A 2007 study in the journal Post-Soviet Affairs argued that the 2004 enlargement of the EU contributed to the consolidation of democracy in the new member states. In 2009, Freie Universität Berlin political scientist Thomas Risse wrote, "there is a consensus in the literature on Eastern Europe that the EU membership perspective had a huge anchoring effect for the new democracies."

The official EU media (the speeches of the European Commission) frequently referred to the enlargement to the CEE region as "an historical opportunity" and "morally imperative", which reflected the desire of the EU to admit these countries as members, even though they were less developed than the Western European countries.

CEE countries wanted to consolidate their democracies through joining Western world international organisations (including participation in European integration) which would ensure the newly emerged democracies would not fall back under Russian control. The EU and NATO offered a guarantee of this, and the EU was also seen as vital to ensuring the economic success of those countries. However, the EU's desire to accept these countries' membership applications was less than rapid. The collapse of communism came quickly and was not anticipated. The EU struggled to deal with the sudden reunification of Germany with the addition of its poorer 17 million people and, while keeping its monetary union project on track.

States in Central and Eastern Europe persisted and eventually remaining issues were cleared. The US also pressured the EU to offer membership as a temporary guarantee; it feared expanding NATO too rapidly for fear of frightening Russia. Although eventually trying to limit the number of members, and after encouragement from the US, the EU pursued talks with ten countries.

Hier finden Sie das Programm zum Download: Programme AUB-KAS Conference.pdf


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Andrássy Universität Budapest
Pollack Mihály tér 3,
1088 Budapest
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Tom Körner

Tom Körner

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Europabüro Brüssel