The Ulster Unionist resignations from the fledgling Belfast administration mean that only a large-scale act of IRA weapons decommissioning can rescue devolution from temporary and perhaps permanent oblivion.
The heartening fact for those who support the administration, and the peace process in general, is that the signs have never been more favourable that something substantial from the IRA is on the cards.
As things stand, the message from a range of sources – security, political and republican – is strikingly and unusually in accord. The word is that a major move on guns is eminently possible.
Stretching back over the past seven years, Irish and British newspapers have printed scores of stories predicting that decommissioning was about to happen. This time, finally, they could be right.
Sources who advised against optimism in the past are now saying that things could be different. People on the security side say the IRA seems to be gearing up for some move, and looks prepared to act if the conditions are right.
People on the political side say that Sinn Fein is locked in negotiations involving London, Dublin and the Unionist party, with the republicans seeking concessions on policing, demilitarisation and the future stability of the assembly. These are only likely in exchange for republican movement on guns.
Republicans say the Sinn Fein president, Gerry Adams, is involved in intensive contacts. Sinn Fein, which is normally reticent on such points, is signalling that a historic move is possible if the terms are right.
On past experience, any breakthrough would automatically be hailed by London and Dublin as significant. The question is how even a dramatic move by the IRA would be viewed within the Protestant and Unionist community.
That community has clearly lost much of its faith in the Good Friday Agreement over the past year and more, plaintively complaining that republicans and nationalists have made huge political gains at its expense.
In political terms, David Trimble would have to be so impressed by the move that he would be prepared to try to sell it to his party. Many regard the initial endorsement of the accord as a mistake, and will not be easily persuaded to give it another chance.
Even a decommissioning act, in other words, will not guarantee that the Agreement will, after its years of instability, finally be put on a firm footing. It is more likely to open a new phase with almost as much uncertainty.