BRUSSELS, Belgium -- Seeking to project a spirit of unity, European Union leaders struggled to overcome differences at a key summit Thursday aimed at adopting a historic constitution for a united post-Cold War Europe.
With key differences unresolved and the wounds of electoral defeat still fresh, the meeting has become a test of whether the 25 EU leaders can see eye-to-eye over divisive issues like power-sharing and which official should fill the EU's top job.
French President Jacques Chirac told reporters, "I have a feeling that a deal is possible."
The meeting comes six months after the EU's first attempt to adopt a constitution collapsed in acrimony, and leaders were determined not to fail twice.
"If we complete this, it will be European history. It is not going to be easy, but we will do our very best," said Ahern, whose country holds the EU presidency and was chairing the talks.
Only a week ago in European Parliament elections, voters around the continent showed their unhappiness with incumbent governments, the EU's expansion ambitions and its complex decision-making process.
EU leaders also were looking for a successor to European Commission President Romano Prodi, who steps down after five years at the helm of the body that runs the EU's day to day affairs.
"Europe on the international stage grows day by day, European involvement in so many regions of the world, we need somebody who can competently deal with that," Ahern said.
Belgian Prime Minister Guy Verhofstadt was a top contender, backed by France and Germany. But Britain and Italy opposed him because of his ardent opposition to the war in Iraq.
Other contenders include Jean-Claude Juncker and Anders Fogh Rasmussen, the Luxembourg and Danish premiers, outgoing European Parliament President Pat Cox and Chris Patten, the EU external relations chief.
If adopted, the constitution will likely be the most ambitious document in EU history.
Key differences dealt with distribution of power. Poland and Spain opposed a proportional voting system that would effectively reduce their relative say in the club.
Ahern was working on complex compromises taking into account national populations, and Polish Prime Minister Marek Belka said Ahern was moving "in the right direction."
Belka said an unfair voting formula would be a "recipe for disaster," and called for a safety net whereby no decision is adopted if four countries, representing 25 percent of the EU's 455 million population, are opposed.
"What is very important is a mechanism that will provide not only voting efficiency but also a solidarity, and interests of broader groups of countries. A simple majority voting may be very efficient, but it leaves sizable groups of countries unsatisfied," Belka said.
Ahern said he would aim to "strike the right overall balance" and said the leaders appeared to be "closing in on agreements" in some areas. "We've heard different views today, I don't think they're unbridgeable."
Then, there's the matter of God.
A handful of countries, led by Poland and Italy, oppose the current preamble of the constitution, which mentions the importance of religion in European culture but does not specifically mention God or Christianity.
"We will fight like lions" on that issue, Belka said.
France, Belgium and others say a reference to the divine would violate the principle of separation of church and state.
Meanwhile, Britain is still fighting to keep its veto right over taxation, social security and criminal law, areas in which the constitution proposes to move to majority voting.
Even if they reach agreement, a significant hurdle remains because all 25 countries must formally ratify it.
At stake is a document that would change how the EU works, streamlining its complex institutions and boosting its image on the world stage by creating posts for a president and a foreign minister.