We knew from the exit polls that the Northern Ireland majority in favour of the agreement was likely to exceed 70 per cent - which meant that over half the Northern Protestant community had joined with the overwhelming majority of the rest of the people of this island in endorsing the agreement. But the moment of profound emotion, which will remain with many of us for the rest of our lives, was yet to come: it was the instant at which the Returning Officer said Seventy-One Point One Two Per Cent.
As a great cheer arose in that Belfast hall it struck me that we had perhaps just seen the long-drawn-out tragedy of Northern Ireland move, at a single stroke, out of current affairs and into history.
That moment meant very different things to different people. To many fearful and to some bitter unionists in Northern Ireland, it must have seemed a moment of loss, perhaps even of doom. And for tens of thousands in that part of our island - but also here and in Britain - who have lost spouses or children or parents or other close relatives or friends, their emotions, whether positive or negative about the agreement, must have been infused with deep sadness and a sense of waste. Feelings like: was it all worth that life, why could peace not have come sooner and, most hurtful of all, are the murderers to be rewarded with premature freedom? A moment of mixed emotions for many. But also a moment of no emotion at all for a lot of people in the Republic. Sadly, at least some of the low poll here reflects a sense of non-engagement, or disengagement.
The part of me that is Northern has always resented this Southern negativism. Emotional partitionism is hurtful to anyone with roots in the North - just as the crude anti-partitionism of past decades, the Southern "claim" on the territory of Northern Ireland, was infuriating to many who hoped that one day sundered North and South could be brought together again in peace.
But whatever resentment Southern partitionism still evokes is for me offset by the sense of finding myself at one with the great majority of people here who have now finally abandoned the old almost colonial attitude to the North - symbolised by the phrase I used to hear: "Give us back our lost counties." We have, at last, accepted the principle of reunification only with the consent of a Northern majority.
The results of the referendums North and South are a starting-point. The politicians in the North, in this State and in Britain whose combined dedication, skill and leadership have brought us to this point now have to apply all these qualities to building the new political structures provided for in the agreement. The main burden falls on those Northern Ireland political leaders whose remarkable skills have given us this agreement: men like John Hume and Seamus Mallon, David Trimble, Gerry Adams and Martin McGuinness. And their job will not be made easier by the unionist opponents of the agreement.
But they now have the wind at their backs and their opponents are demoralised. Moreover, the structure of the institutions to be established under this agreement offers full protection against their being wrecked. The 60 per cent overall support, and the threshold of 40 per cent unionist support which together are required for the establishment of the executive committee and the North-South bodies are well within the grasp of the leadership of the Yes parties - and the opponents of the agreement have no hope of securing enough votes in the impending election to wreck the new structure.
There is only one point of potential vulnerability - the decommissioning issue. But we should not be too pessimistic on this score. First of all, Gerry Adams reiterated on Saturday his intention to fulfil the obligation imposed by the agreement on Ministers to "affirm their commitment to non-violence and exclusively peaceful and democratic means and their opposition to any use or threat of force by others for any political purpose". And nothing in the events of the past five years suggests that he intends to prejudice Sinn Fein's involvement in the government of Northern Ireland and in the North/South bodies by leaving himself open to the accusation of having failed to fulfil this pledge.
Nor we can ignore the fact that Sinn Fein will co-operate with the decommissioning sub-committee of the Mitchell Commission. And Gerry Adams has used language which has implied that if this matter is left to him and his colleagues, they will deal with it.
It should be clear that Sinn Fein's ambitions would not be served by taking a position that would make it politically impossible for David Trimble to join in forming an executive committee. We are long past the time when Sinn Fein's ambition is confined to the simple pleasure of wrong-footing unionists.
It has been notable that in Sinn Fein's statements about decommissioning, the emphasis has always been on the unwillingness of the IRA to act in a way that would imply that it has been defeated. So arms will not be "surrendered". But that approach may not exclude some other kind of action that would deal with this problem.
Ed Moloney's analysis in yesterday's Sunday Tribune is significant. He pointed out that out the "no decommissioning" pledge in the IRA's April 30th statement was immediately followed by the sentence "This issue, as with any other matter affecting the IRA, its functions and objectives, is a matter only for the IRA, to be decided on and pronounced on by us."
One is led to wonder why it was felt necessary to qualify in this way the apparently intransigently negative character of the immediately preceding sentence.
Ed Moloney went on to point out that Mitchel McLaughlin, who always chooses his words with great care, and who has been employed more than once to signal significant shifts in the Sinn Fein/IRA position, made the following statement about decommissioning a few days ago: "People understand that it will, when it happens - and it will happen - be a voluntary process by those who presently control weapons." That represented a very significant qualification of the "no decommissioning" pledge.
Finally, there must be some concern within the IRA about the fact that the retention of weapons and explosives in dumps the location of which is known to dissidents creates a real danger of continued violence. Such a development would make the demilitarisation of the security forces in Northern Ireland, and the re-emergence of an unarmed police force, such as existed briefly in 1970, impossible to achieve.
And without a radical change in policing methods, Sinn Fein's position within an executive committee would be extremely uncomfortable.
Realism rather than optimism thus leads me to believe that the only remaining potential obstacle to the full implementation of the Agreement - decommissioning - is likely to be removed in the months ahead.
And that will certainly inaugurate a new phase of Irish history.