A new Commission - and president thereof - will be chosen before the end of the Irish presidency. Denis Staunton examines the contenders.
In the week before Christmas, 20,000 Commission officials received an email from Romano Prodi wishing them a Happy Christmas. Before listing his achievements during the past year, Mr Prodi mentioned that this could be the last time he would send such a greeting as Commission President.
Mr Prodi's Commission remains in office until October but EU leaders must choose his successor when they meet in June, making the search for a new Commission President one of the most important tasks of the Irish Presidency.
The leaders could, of course, ask Mr Prodi to remain in office for a further five years but even he acknowledges that his reputation as a weak, gaffe-prone leader makes this unlikely.
Traditionally, Commission Presidents are chosen alternately from the centre-right and the centre-left, so that Mr Jacques Delors, a Socialist, was succeeded by Jacques Santer, a Christian Democrat, who was succeeded in turn by Mr Prodi, who led a left of centre government in Italy.
The pressure to choose a centre-right candidate this year could be reinforced by the outcome of June's European elections, after which the conservative European People's Party is expected to be the biggest party in the European Parliament.
Neither Mr Delors nor some of his predecessors led a national government but EU leaders have tended in recent years to choose a Commission President from among their peers - serving or former heads of state or government with at least two years experience in office.
It is widely accepted that the next Commission President will not come from one of the new member-states.
On these criteria, five current EU leaders are eligible for the job - Spain's Jose Maria Aznar, Italy's Silvio Berlusconi, Austria's Wolfgang Schuessel, Luxembourg's Jean-Claude Juncker and the Taoiseach, Mr Ahern. Among former centre-right prime ministers, Belgium's Jean-Luc Dehaene is understood to be eager to be considered.
Mr Aznar, Mr Berlusconi and the Taoiseach have ruled themselves out of the contest, leaving Mr Schuessel, Mr Juncker and Mr Dehaene. Britain vetoed Mr Dehaene the last time he was considered and although the next Commission President will be chosen by qualified majority, the whiff of past rejection may linger too strongly for him to succeed this time.
Mr Schuessel remains tainted by his decision in 1999 to enter government with Mr Joerg Haider's far-right Freedom Party, which prompted all 14 other EU leaders to boycott him for six months.
This leaves Mr Juncker, who speaks French, German and English perfectly and enjoys the reputation of a "good European" with excellent political skills.
Mr Juncker's problem is that he is from Luxembourg, which has produced two previous Commission Presidents - Mr Santer, who resigned with his entire commission amid allegations of cronyism; and Mr Gaston Thorn, who is widely judged to be the dullest figure ever to occupy the job.
Some EU leaders will be reluctant to give Luxembourg a third stint at the top job; others, especially in the new member-states, may fear that Mr Juncker is too close to France and Germany for comfort. If the leaders reject all the candidates from the centre-right, they could consider Sweden's Goran Persson, Denmark's Mr Anders Fogh Rasmussen, Belgium's Mr Guy Verhofstadt or Greece's Mr Costas Simitis. Finland's former prime minister, Mr Paavo Lipponen, has been in Brussels regularly in recent months, raising suspicions that he is looking for a job.
Alternatively, the leaders could look beyond the ranks of prime ministers to figures such as the much-admired Justice and Home Affairs Commissioner, Mr Antonio Vitorino, or the President of the European Parliament, Mr Pat Cox.
Senior British officials talked up Mr Cox's cause during the Autumn but they have backtracked since then and are whispering that the next Commission President should be Scandinavian.
To be considered, Mr Cox would have to be nominated by the Taoiseach, a prospect that the Munster MEP's closest friends admit to be remote.