"The 2004-2007 enlargement of the European Union from 15 to 27 countries is an achievement of which all EU governments should be proud. But the outlook for future enlargement is darkening, thanks to some pig-headed behaviour among members and applicant states," reads the article.
"The EU needs the courage to resolve the disputes blocking enlargement. The Balkans and Turkey are fragile, vulnerable and strategically important. If they feel they are unwanted, the price the EU will pay will be the greater," the FT said.
The newspaper recalls that last week Germany's Christian Democrats, led by Chancellor Angela Merkel, adopted a manifesto for June's European parliament elections, which says that because the EU's latest expansion required such effort, "the CDU stands for a phase of consolidation, during which the strengthening of the European Union's identity and institutions takes precedence over further EU enlargement".
The CDU makes an exception for Croatia, whose admission it would not delay.
"But Croatia's membership bid is in trouble anyway. That is because Slovenia, hoping to force concessions from its former Yugoslav neighbour in a bilateral maritime border dispute, paralysed Croatia's accession negotiations in December. Nationalist rhetoric on both sides has restricted the scope for compromise."
"All other EU governments oppose Slovenia's attempt to exploit its membership at the expense of a future entrant. But the EU operates by consensus, so Slovenia gets away with it."
The newspaper also cited the example of the internationally recognised Greek Cypriot government of the divided island which is obstructing Turkey's accession talks, "partly because they have always been hostile to Turkish membership and also because they hope to gain leverage in negotiations with the Turkish Cypriots over a Cyprus settlement."
Furthermore, Macedonia has been an official EU candidate since 2005 but Greece objects to its neighbour's use of "Macedonia" in its name. It says this implies a threat to Greece's territorial integrity, cultural heritage and national identity," the newspaper said among other things.