LISBON, Portugal – European Union leaders sought Thursday to set aside their national differences and unite behind a new EU treaty designed to give their 27-nation bloc a more influential say in world affairs.
But they launched a two-day summit in the Portuguese capital amid 11th-hour political squabbling over the final text of the document that aims to translate the bloc's economic might into a bigger diplomatic punch.
The treaty would accelerate decision-making so that EU member countries can act more swiftly on global issues such as defense, energy security, climate change and migration.
European Commission President Jose Manuel Barroso, the bloc's most senior official, warned that the continent risks seeing its international influence diminished if it remains unable to take a common stand on pressing questions. "We need this agreement," he said upon arrival.
German Chancellor Angela Merkel was cautious, saying she expected "difficult" talks to secure a deal, though she said the leaders "are now just a few millimeters from the finish line."
British Prime Minister Gordon Brown — attending his first EU summit at Britain's leader — backed the draft treaty, assuring critics at home that it guarantees British sovereignty in justice, home and foreign affairs and security issues.
"On these major issues ... the British national interest is protected," Brown told a news conference.
But Poland's president arrived holding out for more voting rights.
"We don't want anything more than what has already been agreed," Polish President Lech Kaczynski said. "Otherwise, we will have to put off this discussion."
And Italy's Prime Minister Romano Prodi said he would not endorse the treaty unless his country gets more seats in the European Parliament. The draft treaty foresees a 750-seat EU assembly — down from 787 — which would see Italy lose six of its 78 legislative representatives.
Italy "will say 'No,' without hesitation," to the treaty if its demand is not met, Prodi said.
Reservations by Italy and Poland could scuttle the draft treaty and deliver another setback for closer cooperation that would severely damage the EU's credibility.
"We should all be aware that public opinion wouldn't understand if we don't get an agreement," Luxembourg Foreign Minister Jean Asselborn said. "We can't talk and talk again and then talk some more."
Also, doubts remained about whether the leaders would subject an agreement to referendums in their countries. Many Europeans are uneasy about the possibility of a superstate that could neglect the concerns of individual countries.
The treaty under discussion is a revised version of a draft constitution that was approved by EU leaders in 2004 and was intended to mark a new era in European integration. But French and Dutch voters rejected it at the ballot box the following year.
Poland, which goes to the polls Sunday, refused to endorse new voting rules that would allow more decisions by majority instead of unanimous consent. Warsaw fears those rules — devised to prevent decisions being held up — could weaken its influence over EU policy.
"An EU where a minority imposes its will on the others may be a union headed for disintegration," Polish Prime Minister Jaroslaw Kaczynski said in Chorzow, Poland.
Neither Britain nor Poland are to sign up to a planned bill of rights.
The new treaty has kept some details from the defunct constitution, including an EU foreign minister, a smaller EU executive arm and an exit clause for nations wanting to quit the EU. The new document scrapped a planned EU flag and anthem.