It was probably unrealistic to think that the final stage of the 10-year-old peace process could be carried through in a mere 30-hour negotiating session presided over by the two prime ministers, writes Garret FitzGerald.
Deep unionist divisions continue to bedevil this tortuous process, so that even at the point when McGuinness and Adams appear to have brought their followers finally to accept the abandonment of violence, decommissioning, and involvement in policing, David Trimble has felt it necessary to have these moves backed by an inevitably controversial system of monitoring, verification and possible sanctions.
By Thursday it was being reported that the two Governments will incorporate something like this into their non-negotiable proposals for a final settlement. Apparently the existing legal provision for unilateral action by the British government to suspend the Assembly, and thus the Executive, is to be repealed. Instead there is to be an Independent Monitoring Body, two of the members of which will be appointed by Britain, (one with cross-community support in Northern Ireland), one by Ireland, and one by the United States.
While details of these arrangements remain to be worked out, it seems likely that any proposed sanction for a body or individual found to be in breach would then be referred to the existing implementation body for the agreement.
At this stage Sinn Féin is expressing opposition to any arrangement that might involve sanctions. But Gerry Adams's words seem to leave some room for further reflection by Sinn Féin/IRA. He said Sinn Féin was not against parties or party members being held to account if they were in breach of commitments or pledges of office or house rules. What it could not accept was "the government stepping outside the Good Friday agreement to bring in sanctions which are aimed at us for something another organisation may or may not be responsible for".
This wording could be a further attempt to distinguish between Sinn Féin and the IRA - the former not to be held responsible in the political forum for anything that the latter might do in the shape of paramilitary action. But Sinn Féin also has an interest in not being blamed for the actions of dissident paramilitaries. They may also have an interest in having a public guarantee against any future British government - possibly of a different political complexion - going back on the deal now being worked out.
Most of us know that this would not happen, but Adams and McGuinness have to convince their suspicious hardliners of this.
And as Sinn Féin also seeks the abolition of the British government's unilateral power to suspend the Assembly, its abolition - and the substitution of an alternative method of guaranteeing the integrity of the process that would involve representatives of the Irish and US governments - may have positive elements from their point of view.
For Sinn Féin, the de facto transfer to an international body of British sovereignty over the working of the system of government of Northern Ireland must surely have some attractions.
It could be presented to their supporters as an important step towards their objective of ending British sovereignty over the North. Moreover, it is difficult to see much likelihood of Sinn Féin losing anything by accepting these proposed arrangements. For, having destroyed their arms and explosives, having announced an end to paramilitary violence, and having joined in the running of policing in Northern Ireland policing - which is what Sinn Féin/IRA at last seem ready to do - that organisation can have no interest in repudiating its commitment to the democratic process by reverting to violence.
To do so would fatally undermine its political credibility, built up painstakingly over the past 10 years, and would seriously weaken its capacity to win votes for Sinn Féin either North or South.
To take this view is not to be naïve about Sinn Féin, but rather to be brutally realistic. The last 10 years have shown us that its leaders are clever politicians who have a clear vision of where they want to go. They are much too astute to mess all that up by reverting to violence - although we can, of course, expect some tough political tactics to be employed by them in both parts of our island, including populist wooing of the disillusioned and of those disadvantaged people who do not perceive the established parties as committed to their interests.
All this won't be pretty, but it won't be war. I trust Sinn Féin in one way only: to pursue ruthlessly what it has identified as its political interest, as it has clearly been doing unremittingly for the past 10 years. These interests, most obviously, do not lie in a reversion to a murder campaign. Of course many unionists will be hard to convince on this matter. Most will probably be persuaded only by an actual experience of peace over a number of years.
David Trimble's problem, however, is that in order to survive in the immediate future he has to convince a lot of his party members, and some at least of the wider unionist family, of this reality now, well before they have a chance to see it all for themselves. The adoption of this proposal for a monitoring body could help him achieve this.
There is, however, another aspect to this arrangement to which I suspect Trimble may not have given sufficient thought. Frank Millar, an astute observer of events in Northern Ireland, commented in this paper last Wednesday that in seeking a "sanctions" regime that would have to be based upon an adjudication of feared IRA future actions by an independent body, Trimble is effectively seeking a transfer of the ultimate authority over Northern Ireland's form of government from the British government to that outside body.
It is remarkable that unionists should be led by their distrust of and hostility towards British governments - particularly towards one they apparently perceive as "soft" on the IRA - to demand that decisions on Sinn Féin/IRA's commitment to peace be transferred to such an international body, where half the membership would apparently come from outside the UK.
Politics in Northern Ireland certainly takes some curious twists.