The current impasse at Stormont brings to mind Benjamin Franklin's words at the signing of the US Declaration of Independence: "We must indeed all hang together, or, most assuredly, we shall all hang separately."

This applies to the Ulster Unionist and Sinn Fein leaderships. They may not particularly like each other, but they "most assuredly" need each other at this point.

If there is no deal on decommissioning, the peace process will effectively be put on hold for several months, fuelling concerns that it will suffer a slow and agonising death. That scenario would be curtains for the leadership of Mr David Trimble, who staked his all when he said Yes last Good Friday.

Likewise, if the Sinn Fein leaders make the wrong call over the coming days, they too are destined for the dustbin of history. They need to reach out to one another: the historic compromise starts here.

Initial reports of yesterday's hour-long meeting between the UUP and Sinn Fein leaderships do not suggest a meeting of minds. Insiders said the UUP asked what Mr Adams meant last week when he spoke of "stretching the republican constituency" and was treated to a "mantra" about the inability of Sinn Fein's leaders to deliver decommissioning in the terms demanded by unionists. There is now a cynical view in some unionist circles that Mr Adams's phrase was just a rhetorical flourish aimed at getting Bill Clinton off his back.

Likewise, Mr Gerry Kelly's visit to republican prisoners at the Maze on Monday is being dismissed by unionists as a "stunt" aimed at providing political cover for Sinn Fein's hardline stance on weapons. They based their judgment solely on the comments made by Mr Kelly after he had spent six hours with the prisoners rather than on a full report of the discussions which are thought to have been much more wide-ranging than a mere reiteration of republican policy on decommissioning.

It is understood Mr Trimble spelt out to Mr Adams that he required not one but several decommissioning "events": the first to be followed by another shortly afterwards with the amount of armaments increasing each time.

It was not clear whether he was putting the bar higher because he did not want a deal or was taking a more hardline position as a tactic, with the ultimate intention of accepting a compromise.

Speculation that the British Prime Minister and the Taoiseach will have to travel to Stormont on Saturday is intensifying, but there is a proviso: if there is no chance of success, Mr Blair and Mr Ahern won't travel. Sceptics in the unionist family are distinctly wary of the current "mood music". Their memories of last Good Friday are still fresh: that was a wake-up call like they had never had before and they are on their guard for another dramatic move by "Nimble Trimble".

This promises to be a fateful weekend in Northern Ireland's history. Ideally, from the two governments' viewpoint, the Assembly should be in a position to meet on Monday to allocate ministerial posts so that the transfer of power can be approved at Westminster in time for Easter.

Whatever about stretching their constituencies, Northern politicians have shown their ability to stretch deadlines. Nobody will complain if a few extra days are required to put a deal in place, but at the very most there can only be 10 days to a fortnight's life left in this stage of the peace process.

The indications last night were that the positions of both unionists and republicans had hardened over recent days. The intervention by the British Home Secretary, Mr Jack Straw, in the prisoner release scheme soured the republican mood considerably. In the fullness of time it may turn out to be a tactical master stroke which put pressure on republicans to ease their stance on arms, but insiders were last night bemoaning it as an ill-timed lapse of judgment, a serious setback to conciliation efforts and an unnecessary source of annoyance to Dublin and Sinn Fein.

All is not entirely lost. Amid all the sound bites and the grandstanding there is an underlying sense that both sides are beginning to recognise the need to make some fundamental shift - although the precise nature of that shift may not even be discernible at this stage to the participants.

At times like these, politicians and officials put on their lateral thinking caps and a fair amount of attention is being given to the possibility that a middle way could be found between the concept of weapons being "decommissioned" or simply "out of commission". Bright ideas are being floated about burying the guns 30 feet in the ground, with Gen de Chastelain and his commission acting as honest brokers who will watch the entombment of the Armalites.

But after such knowledge, what forgiveness? Can constitutional governments permit arms dumps at known sites to continue in existence like a political version of a toxic time bomb?

There was an interesting hint of the way forward from a senior Dublin politician who said an acceptable assurance of the republican movement's peaceful intent was worth far more than a token consignment of arms which could be easily replaced. That would not square with the position of the Ulster Unionists, who demand "product" rather than words. But it may be all that is on offer. As with old age, the unionists may not like it, but it may be preferable to the alternative.