The European Union entered a new era last night after the leaders of its 25 member-states agreed a constitutional treaty, write Denis Staunton and Deaglán De Bréadún in Brussels.
The new treaty overhauls EU structure and defines the division of power between national governments and European institution.
The leaders reached agreement in Brussels shortly after 10.30 p.m., rewarding the Taoiseach's conduct of the negotiations with a standing ovation. The deal represents the climax of Ireland's six-month EU presidency, which rescued the negotiations following the collapse of a summit last December.
The Taoiseach said the leaders had achieved "a fundamental advance" for the EU, describing the constitution as "a great achievement for Europe and a great achievement for all Europeans".
Flanked by the Commission President, Mr Romano Prodi, the President of the European Parliament, Mr Pat Cox, the Minister for Foreign Affairs, Mr Cowen, and the Minister of State for European Affairs, Mr Roche, the Taoiseach said the outcome was one that everyone could endorse.
"This is a win-win solution and it enables everyone to say that their concerns have been accommodated . . . The constitutional treaty we have agreed is a very significant milestone in the evolution of the EU," he said.
Mr Ahern thanked all those who helped with "a ship that has been safely docked today" and said that the constitution explains Europe in a way that "the ordinary person in the street" would understand.
Mr Prodi described the constitution as the greatest achievement of the past five years. It "attests to democracy in its purest essence", he said.
The delight that greeted last night's agreement was slightly tempered by the summit's failure to agree on a successor to Mr Prodi as President of the European Commission. The leaders agreed to return to the search "at a later date".
Last night's agreement followed two days of intense negotiations in Brussels, including six hours of bilateral consultations yesterday afternoon. Yesterday's talks were dominated by an attempt by the EU's smaller states to modify proposals that will change the way governments vote in the Council of Ministers and reduce the size of the Commission from 2014. The presidency addressed these concerns by making minor changes to the text, while maintaining the basic thrust of the proposed changes.
Under the treaty, a qualified majority will be defined as 55 per cent of member-states, "comprising at least 15 of them" and representing at least 65 per cent of the EU's population. The requirement of 15 member-states effectively raises the population threshold, at least until the EU takes in new members.
On the Commission, the final draft stated that from 2014, "the Commission shall consist of a number of members, including its President and the Union Minister for Foreign Affairs, corresponding to two-thirds of the number of member-states, unless the European Council, acting unanimously, decides to alter this figure".
This rendezvous clause removes the automatic nature of the reduction in the Commission's size, but the requirement of unanimity ensures that the change is almost certain to go ahead.
EU leaders and officials were enthusiastic in their praise of the Irish presidency's handling of the negotiations, with France's President Jacques Chirac describing Ireland's as "the best presidency I have ever experienced".