Next week's EU summit in the Swedish city of Gothenberg will tell a tale of two leaders.
Mr Tony Blair will stride into the meeting as a victorious warrior king, fresh from a historic election victory. The British Prime Minister's status among his peers has been enhanced enormously, not least because his renewed mandate will allow him to play a more adventurous role on the European stage.
When the Taoiseach, Mr Ahern, arrives in Gothenberg, he will find plenty of sympathy among his fellow leaders. They know that, as the only member-state to hold a referendum, Ireland faced the biggest hurdle in ratifying the Nice Treaty.
"Nobody wants to make it more difficult for the Irish Government. The other leaders know that there, but for the grace of God, go they," one senior EU official said.
But as he soaks up the kind words, the Taoiseach will have reason to feel uneasy. The animal instinct that drives political leaders to worship success makes them contemptuous of failure, a condition they respond to as if it was infectious. Mr Ahern should be in no doubt that his fellow leaders will regard the rejection of the treaty as a massive political failure on the part of the Government.
Until yesterday, nobody in Brussels considered the possibility that the proposal would be defeated. As late as Wednesday night, one senior EU diplomat was astonished that the result could be in any doubt.
"The Irish will say No? After all the money we've given them? You can't be serious," he said.
By lunchtime yesterday, as news of the early tallies reached Brussels, Commission officials and EU diplomats reacted with shock. Throughout the afternoon, senior figures in the Commission worked with the Swedish EU Presidency on a joint response to the result.
As they drafted a statement in the names of the Commission President, Mr Romano Prodi, and Sweden's Prime Minister, Mr Goran Persson, the officials consulted the Irish Government to co-ordinate their response.
The statement expressed disappointment at the referendum result and expressed the hope that Ireland would eventually ratify the treaty. But it made clear that any accommodation of Ireland's concerns about Nice must be reached "without changing the substance of the Nice Treaty".
All EU member-states are agreed that the core of the treaty cannot be renegotiated. The compromises reached at Nice are so complex and inter-dependent that to unpick one element would lead to the unravelling of the whole agreement.
Among the most controversial issues in the referendum campaign was Europe's emerging common security and defence identity. Denmark, which is a member of NATO, enjoys an opt-out preventing it from taking part in any EU decisions with military implications.
If Ireland were to secure a similar opt-out, Europe's new Rapid Reaction Force could probably survive without our contribution of fewer than 1,000 soldiers. But officials warn that such a step could prevent Ireland from participating in EU debates about controlling arms sales and would mean that Irish forces could not take part even in humanitarian missions.
Senior EU officials stressed yesterday that Ireland still has 18 months to ratify the treaty and Irish officials agree that yesterday's result calls for a period of reflection before any decisions are taken.
In the meantime, the Gothenberg summit will reaffirm the EU's determination to press ahead with negotiations with the candidate countries. Other EU member-states will hold firm to their own timetables for ratifying the treaty.
Reflecting on Ireland's possible loss of goodwill in the EU following yesterday's result, a Commission source suggested that the loss of political capital could be significant and would affect the State's national interests.
"It fundamentally weakens Ireland's role in the EU. It's going to make Ireland's position at every level, from the lowest official going into a working meeting to the very highest, more difficult," he said.
One effect of the result will be to reinforce a growing feeling among our EU partners that, after reaping the benefits of EU membership for almost 30 years, Ireland is no longer fully committed to the European system of co-operation. Every Irish position will be viewed through the prism of this perception and it may be more difficult to form the flexible alliances that have served the State's interests so well until now.
An early test of our partners' attitudes will come next year when spending on the Common Agricultural Policy comes up for a mid-term review. Germany wants to overhaul the farm subsidy system and France has hinted that, once next year's elections are out of the way, it may be willing to do a deal.
Failure to make the right alliances could cost Irish farmers millions of pounds and lead to a deal that would place Irish agriculture at a disadvantage.
If Irish policy-makers doubt that goodwill matters in Europe, they should look at the case of Spain, which has enraged other member-states with an attempt to link the future of cohesion funding with rules about allowing citizens from candidate countries to work in the EU.
Some large member-states, notably Germany, are so outraged by Spain's behaviour that they are blocking a declaration at next week's summit acknowledging Madrid's concerns.
Nobody yet knows the shape of any deal that would allow the Government to call a new referendum on Nice, but everyone agrees on the necessity for calm, tact and delicate diplomacy. This makes it all the more astonishing that the Tanaiste, Ms Harney, should choose this moment to reiterate her opposition to further European integration.
Ireland's partners are willing to help the Government out of the difficulties presented by yesterday's result. But if they think that senior Irish politicians are using Europe as a whipping boy, their patience could evaporate sooner rather than later.