EU and Croatia remind world the Union is still working

"It is with love and pride that I remember all those who laid down their lives for a free Croatia," Kosor said at a ceremony in the EU headquarters in Brussels.

"We are not surrendering our hard-won sovereignty, but investing part of our hard-won sovereignty ... The response [to the financial crisis] is more Europe not less. This holds true for Europe as for Croatia - Croatia needs more Europe, not less," Josipovic said.

The event took place shortly after 26 out of 27 EU countries agreed, in a separate meeting in the same building, to draft a new treaty that will see member states cede control of national budgets to EU institutions.

It also took place amid concern in the Western Balkans and post-Soviet countries that the crisis-hit EU will now close its doors for several years.

Meanwhile, the EU's reputation has taken a hammering in recent months.

Ratings agencies have threatened to downgrade its triple-A economies. Developing countries like China have snubbed requests for financial help. Commentators have said the new EU treaty is the end of democracy and media have made fun of 'incompetent' EU officials and politicians.

For its part, the Polish EU presidency said euro-romanticism is alive and well in the east.

"The decision of Croatia, and the hopes and dreams of other countries which apply for EU membership, show that the EU has a deep meaning - our rules, our values, the European perspective still exert a magnetic pull," Polish Prime Minister Donald Tusk noted.

"Croatia is a lesson to us all ... a lesson that some of the old member states sometimes seem to forget."

European Commission chief Jose Manuel Barroso said the EU door remains open to Western Balkan countries: "We should not let the crisis overshadow this very important policy [enlargement]. The crisis is serious, we all know. But we should not let it affect other countries in the region."

Nobody mentioned Georgia, Moldova and Ukraine's EU aspirations, however.

The red carpet ceremony was not just solemn statements about Balkan wars and Communism - EU leaders clapped, smiled and lined up to kiss Jadranka Kosor on both cheeks.

Belgium's new PM, the bow-tied Elio di Rupo - the first to sign from the EU side - in a moment of levity tried to give back his own pen to protocol staff. But UK leader David Cameron - who caused arguably the worst split in EU history on Friday by keeping Britain out of a new EU treaty - had a jaded look on his face.

Croatia is slated to join the Union on 1 July 2013.

The "happy ending" - in Tusk's words - will come about only if Zagreb passes a European Commission test on fighting corruption and only if the 27 EU countries and Croatia itself (in a referendum) ratify the accession text.

"I am convinced [EU entry] will be endorsed by a great majority," Kosor said.