The Ulster Unionist Party and Sinn Fein are due to lock themselves in critical talks at Stormont today amid waning expectations of a satisfactory outcome to Senator George Mitchell's review of the Belfast Agreement.
Senior British, Irish and pro-agreement talks sources acknowledged last night that Sinn Fein and the UUP must moderate their fixed positions on "guns and government" if the review is to break the political deadlock.
There were no indications of any imminent shift from either side last night. But amid increasing pessimism about the chances of the review succeeding, both the UUP and Sinn Fein were anxious to state that all was not yet lost.
Despite widespread predictions that the review would end in failure this weekend, a leading politician at the heart of the process insisted last night that a conclusion this week was "by no means certain."
Other well-informed sources agreed that, as one put it, "options between total success and absolute failure are clearly being considered."
While no party is predicting a deal to break the devolution-decommissioning deadlock at this time, the great unknown in all the speculation is the personal disposition of Senator George Mitchell.
Parties across the spectrum acknowledged that the senator could conclude his mission is impossible and return to the United States. However, there is a widespread belief that he will not readily pronounce his review a complete failure.
Some of those wishing to retain Senator Mitchell's role are suggesting that he might issue an interim report this weekend, return to the US to consider his conclusions and return, possibly in November, with a set of specific proposals for the parties to consider.
In that context there is gathering interest in a proposal, understood to originate from the Women's Coalition, that a shadow administration might be established as an interim development of the process, with ministers-designate heading Assembly committees in an initial scrutiny role, pending the eventual devolution of powers.
Gen John de Chastelain, the head the international body on decommissioning, has said that it is still possible paramilitary decommissioning will be achieved by May next year, the date for IRA and loyalist paramilitary disarmament in the Belfast Agreement.
Gen de Chastelain told BBC Radio Ulster last night he hoped, and expected, there would be decommissioning by that date. The general said he hoped he was not being "unrealistically optimistic" in his assessment.
Castle Buildings, Stormont is the venue for the final push to end the stalemate. If there is no movement over these coming 48 hours it is expected that Senator Mitchell will prepare a final report for the two governments and the political parties and then make his travel arrangements to return to the US.
"Nobody is being wildly optimistic, I can assure you, but we've been down this road before - remember the deadlock just before the Good Friday agreement - so there is still some hope left," said one British government source.
In the event of the review failing, the two governments would stress that the Belfast Agreement is still in place, and attempt to maintain elements of it which do not necessarily flow from the formation of an executive.
That would speedily open up a new battle over the continued existence of the Assembly and the implementation of the Patten Report. The Sinn Fein chairman, Mr Mitchel McLaughlin, said that the "talking shop" Assembly should fold if the review failed.
A senior UUP negotiator, Mr Dermot Nesbitt, said the Assembly must be allowed continue in existence. "Why should the Assembly close because the IRA would not decommission? That would be ludicrous," he said.