The review can succeed, but it's still 50-50, according to talks sources. "Everything is right now to get a deal . . . but that does not mean a deal will be got," was how one politician locked inside Castle Buildings, Stormont, put it last night.
That's rather having it both ways, although it must be said the spin here was more on the positive than the negative. The quote did capture a sense of where we are. Maybe/maybe not remains the position.
These 48 hours should tell whether Senator George Mitchell will be flying home tomorrow or the next day, leaving behind headlines heralding him as the saviour of the Belfast Agreement.
As David Trimble and Gerry Adams searched for a way out of the decommissioning/devolution logjam at Castle Buildings, 15 miles away in Hillsborough anti-agreement unionists were warning that any deviation from "no guns, no government" could spell the end of the line for the North's First Minister-designate.
Mr Willie Ross, the UUP MP for East Derry, believed Mr Trimble was shaping up for a compromise on that very principle, but predicted that his party leader would not survive such a risk.
Yet Mr Trimble emerged from Castle Buildings yesterday with words suggesting he is a man about to take a calculated gamble.
"Sooner or later this will succeed," he said. He hoped this final stage of the review would be fruitful. "We are addressing the central issue now," he added. That must mean guns, because for unionists that is the central issue.
"Sooner or later" was another interesting line here. It tallies with a suggestion from one senior talks source that the nature of a solution will revolve around a particular form of sequencing first alluded to during the failed "Way Forward" discussions here last June and July.
That solution involves a step-by-step building of trust, which would also lock republicans and the UUP into a process that would be difficult to abandon while it was in train.
It could involve a parallel process whereby the IRA appoints an interlocutor to Gen John de Chastelain's decommissioning body and the UUP accepts nominations to a shadow executive.
This could be followed by the IRA sorting out with the general how decommissioning might take place (the modalities), with perhaps the executive being formally set up.
Next would come a timetable for decommissioning, or actual decommissioning itself, with the creation of the North-South bodies and the other institutions.
It would be an incremental initiative, and not necessarily in that order. The key would be step-by-step reciprocation between Sinn Fein (and the IRA) and the UUP that would build confidence, according to this talks source.
He could not put a timescale on this process, but he added: "It won't mean an executive on Monday." And neither could he say that the two sides would sign up to it. Nonetheless, he said, the idea was being seriously examined by Sinn Fein and the UUP.
Behind all this the central question of which comes first, guns or government, remains to be answered. Such a scenario, however, could create the conditions whereby it could be justifiably argued that the "process of decommissioning" (e.g. IRA interlocutor, then modalities, then a time-frame for disarmament) had started, and that therefore the executive could be formed ahead of actual product being delivered.
"But we have still a way to go in terms of trust," this source emphasised.
British, Irish, Sinn Fein and UUP sources have all highlighted the sense of politicians strenuously trying to do business.
"Last week in London was creating the right ambience for the talks. This week is about creating real engagement, and we've done that," said one insider.
"There is expectancy, but also anxiety," he added, referring to the apparently genuine will to strike an agreement, and the attendant concern that if the balance of risk is not perfect, it could all collapse.
Senator Mitchell has still not produced any paper on what might constitute a deal. Talks sources repeat he will only do that if agreement is realisable. Neither party has so far spelt out its so-called bottom line on how much it can gamble.
This is a high-stakes game, but at some stage over this weekend Sinn Fein and the UUP must show their cards.