European Diary: Three months before they join the European Union, citizens of the new member-states may feel they are facing a frosty welcome. All but two current member-states will restrict access to their labour markets for at least two years; even Britain and Ireland are hinting at rules to prevent central and eastern Europeans from claiming full welfare benefits.
A two-year debate over the EU's long-term budget plan, which starts today, is likely to offer further evidence of western Europe's lack of solidarity towards the east, as the EU's biggest paymasters call for a union of 25 to manage on the same budget as today's 15.
If this was not enough, questions are being raised about some of the commissioners proposed by the new member-states, who must be approved by the European Parliament before taking office.
At its annual conference in Brussels last week, the conservative European People's Party (EPP) approved a resolution condemning totalitarian communism and calling on "all those who intend to assume a political function in the EU institutions to disclose their professional and political activities in former communist states and to refrain from taking up a European post if they formed part of the repressive communist enforcement agencies, or were involved in crimes against humanity".
The resolution, which was proposed by members of the Hungarian Fidesz party, is non-binding but it has provoked a debate about the proper attitude of the EU to former communists.
Among the 10 nominees for commissioner, Estonia's former prime minister, Mr Siim Kallas, was a long-standing member of the Soviet communist party and Hungary's Peter Balazs was a senior official in the communist government in the 1980s.
Former communists are in power in a number of central and eastern European countries, notably in Poland, where both the President and the Prime Minister have communist pasts. Few people, even in the EPP, are suggesting that former communists should be excluded from office but the call for a closer examination of their past has provoked outrage.
The Liberal leader, Mr Graham Watson, was quick to condemn the proposal.
"The European Parliament is not a court, and should not get involved in legal or quasi-legal matters. It is up to each member-state to deal with its own past, and this should be done at national rather than at European level," he said.
A Commission spokesman took a similar line last week, although he seemed a little embarrassed when an eastern European journalist asked if repressing the civilian population was consistent with the EU's core values.
Mr Balazs believes that the issue can be treated more usefully as a moral rather than a legal question, not least because it is difficult to define what constitutes a communist past.
"These were very special one-party systems but then it is extremely difficult to define that party. One of the big masters of our transition, Imre Pozsgay, said that 'believe us, in our one party there were more colours than in the whole British parliament'. Everything was inside that one party. So party membership really does not say anything. We have ex-party members in all the parties in and outside the Hungarian parliament nowadays. So it really has no meaning," he told euractiv.com, an EU news website.
Mr Balazs favours opening up the archives in former communist countries and establishing who spied upon their neighbours for the secret services.
Among the proposals in the EPP resolution is the establishment of a European research and documentation centre, to continue collecting, assessing and publishing information about totalitarian communism, and the establishment of a memorial museum on victims of communism. The debate comes amid fresh tensions between Germany and some of its neighbours about the proper way to commemorate shared history in a united Europe. Plans to commemorate in Berlin all those deported during and after the second World War have raised fears, particularly in Poland, that Germany's Nazi past is being re-appraised in a way that is more comfortable for today's Germans.
All these disputes highlight a fact about EU enlargement that has been broadly overlooked - its potential impact on memory and identity throughout Europe. From May 1st, the European Union will change, not just geographically and economically, but historically.
