A striking irony of the peace process is that while its central objective was to bring change to Northern Ireland, the changes so far in the Republic have been profound, and have a greater chance of lasting.
The Taoiseach, Mr Ahern, implicitly acknowledged as much yesterday. In relation to the imminent developments in Northern Ireland arising from Saturday's Ulster Unionist Council vote, he avoided using the word historic. "It is clearly not over yet," he said. "It is the start of another phase."
But he had no such caution when describing the implications of the UUC decision for the Republic. Next Thursday, he said, would see "a historic Cabinet meeting to change Articles 2 & 3 and to sign ourselves into the North-South bodies".
In other words, while the progress towards lasting new political institutions in the North may yet turn out to be temporary, the changes to our Constitution on Thursday morning are permanent - and historic.
Not only will we have new clauses in the Constitution. There will also be, for the first time, structures through which politicians, North and South, will come together to do business on day-to-day issues of policy. Over the next fortnight a dizzying sequence of meetings and signing ceremonies will herald what are hoped to be new, lasting structures to allow political business be done on an all-island basis for the first time.
Mr Ahern's comments highlighted the fact that the peace process has not just been about changing political and civil life in Northern Ireland. It has also brought substantial political change to the Republic, reflecting the evolution in how its people see their State and their nation.
Mr Ahern made it clear that the Government no longer saw Articles 2 & 3 as bargaining chips to be given to unionists in exchange for some concession. Changing them was a good idea for its own sake, as the new articles, with an inclusive definition of Irishness but no territorial claim over the North, more accurately reflect the concept of Irishness accepted in the Republic.
"I've long made up my mind that the new wording is a reflection of how we see ourselves in the future, regardless" of what happens in Northern Ireland he said. This statement from a Fianna Fail leader reflects a remarkable political change.
As well as triggering the rewriting of the Constitution's conceptual definition of Irishness, Saturday's UUC decision paves the way for setting up significant new institutions with the capacity to transform political relations between the Republic and the North, and between Ireland and Britain.
Up to now formal political engagement between the Republic and Northern Ireland has happened at senior government level only. Indeed, until serious political negotiations began a few years ago, such engagement was confined to meetings between Irish and British ministers, with Northern politicians margin alised from the process. Historically most TDs and senators had no political engagement with Northern Ireland, save to condemn violence and intransigence from time to time.
However, the direct contact between Northern and Southern politicians that came with the intense political negotiations of the recent years will broaden further when the new institutions begin to operate. And the Government is determined that those institutions will begin to work, and be seen to work, very rapidly.
Within a week of devolving powers on Thursday, the new North-South ministerial council will have an inaugural meeting in Armagh. The Taoiseach and senior Ministers will represent the Government, with the North's First Minister, Mr David Trimble and Mr Seamus Mallon, and possibly others representing the Northern executive.
The Government hopes the ceremonial fanfares will be replaced by real engagement between ministers on routine policy issues as waterways, trade, fisheries, food safety and EU programmes. The six North-South Implementation Bodies, which have interim chief executives and some staff, will be put on a more stable footing. Government ministers are expected to meet their Northern counterparts regularly on policy and co-operation. Through these encounters it is hoped practical and stabilising political contact will grow.
However, in the short term the scope for rapid development of this new strand of political engagement on the island is limited. Christmas will provide a natural break soon and the UUP's February deadline for decommissioning will begin to loom.
The Anglo-Irish Agreement will die next Thursday morning as the new institutions are born, but a new British-Irish Agreement will come into force and will in many ways carry on where the other left off. It will set up structures for co-operation mirroring those of the old agreement, with a British-Irish Intergovernmental Conference replacing the Anglo-Irish Inter-Governmental Conference.
Policy matters where powers have been devolved to the new Northern Ireland and cross-Border institutions will no longer be considered between Dublin and London. Issues such as security, human rights and prisons will remain within the ambit of the east-west institutions.
There will also be a British-Irish council, including representatives of the two governments as well as of the devolved institutions in Northern Ireland, Scotland and Wales, as well as the Isle of Man and the Channel Islands. Inter-parliamentary links will be encouraged, thus involving deputies, senators and Northern Ireland Assembly members in political engagement with each other on many issues.
All these new political structures could, of course, collapse if the political process founders on the decommissioning issue in February. But if they last they have the potential to transform, over time, the way politicians in the Republic see their political relationship with Northern Ireland.
There is also the prospect that this could have a significant party political effect in the Republic as well. Sinn Fein has Dail candidates with significant followings in Dublin South West, Kerry North and Sligo-Leitrim, and in June's local elections, several more put in impressive performances to win local authority seats on the north side of Dublin.
Should the party's sole TD, Mr Caoimhghin O Caolain, be joined by a couple of colleagues in the Dail, it is not inconceivable that the party could find itself holding the balance of power at some stage, with the prospect of entering government.
To make this breakthrough the party has to concentrate on ensuring it is seen as a left of centre party of protest rather than the political wing of a private army. A good performance by its two ministers in the Northern Ireland executive would help, but putting weapons beyond use would help further.
As former SDLP councillor Mr Brian Feeney observed at the weekend, it may turn out to be the political realities of the Republic rather than the North that confront the republican movement with the most persuasive argument for decommissioning.
Mark Brennock can be contacted at mbrennock@irish-times.ie