In July 1971 Brian Faulkner, then prime minister of Northern Ireland, announced a political initiative that was greeted with almost unrestrained welcome by several members of the SDLP. The initiative was the establishment of parliamentary committees in the Stormont parliament, some of which would be chaired by nationalists. One SDLP member - I think it was Paddy Devlin - described the announcement as Brian Faulkner's "finest hour".
Although the reaction of some SDLP members - John Hume for one was far more restrained - seemed excessive even at the time, that initiative seemed to herald a new era in Northern politics. An era that might lead to an accommodation between nationalism and unionism and an end to the then escalating violence.
Four days later the SDLP had withdrawn entirely from Stormont. The withdrawal was prompted by John Hume who, in turn, was reacting to events in his own constituency in Derry. Two Derry youths had been shot dead by the British army and an independent inquiry into the killings had been refused both by Brian Faulkner and the British government.
The disappointed hopes of that initiative are now almost entirely forgotten. So too are the disappointed hopes that arose from a litany of other initiatives - the O'Neill reforms of 1968 and 1969; the Downing Street Declaration of August 1969 (it talked of "equality of treatment and freedom from discrimination"); the prorogation of Stormont in March 1972; the Anglo-Irish Agreement of 1985 which was intended to stifle conflict with institutional kindness.
It is almost universally believed that the success (so far) of the "peace process" and the triumph of the Good Friday agreement guarantee an inexorable, if difficult, passage towards lasting peace. Our optimism should be tempered by recollection of past disappointments. The fact is that this peace process could go wrong, badly wrong.
Its core has been the drawing of the republican movement away from "armed struggle" into "unarmed struggle" through the political process. The achievement, so far, has been the success of this effort at a price that has done no damage to democracy. The principle of consent has been established and an outline of future government agreed.
But it could all unravel.
The IRA was coaxed into a ceasefire in August 1994 by the promise that its political arm, Sinn Fein, would be in all-party talks on a settlement once the guns went silent. Immediately after it had agreed to that, a new condition was introduced, decommissioning. No involvement in talks until decommissioning began.
From the IRA's perspective, the ground rules were changed after it had agreed to a ceasefire. The ceasefire broke down in February 1996. When the decommissioning obstacle was removed the ceasefire was reinstated in July 1997 and a settlement agreed in April 1998.
Now there is an attempt again to change the ground rules and again on the issue of decommissioning. Participation by Sinn Fein was not a precondition in the Good Friday agreement to Sinn Fein's participation in an executive. Now it is being made so and not just by the unionists, but, it seems, by the British and Irish governments as well.
If solemn agreements democratically entered into by governments and parties, along with Sinn Fein, are abandoned, then how can it be said that the "unarmed struggle" can work?
The republican movement was given an object lesson in the selective deployment of "armed struggle" in February 1996. Immediately after the murderous bombing of Canary Wharf, the Irish and British governments reversed the previous insistence on decommissioning before talks could be started.
Might not another "armed struggle" nudge do the same now in removing the decommissioning roadblock again? It would not be surprising if some people in the IRA were thinking this and if these same people were oblivious to the danger that such a "nudge" could propel Northern Ireland back into uncontrollable civil conflict.
The "uncontrollability" of events is much underestimated by politicians and, more so, by paramilitaries. We simply do not know what the outcome may be of the murder of Rosemary Nelson on Monday, of the escalated schedule of Orange marches at Drumcree over the coming months, of the breakdown of talks on the establishment of an executive.
Still less does anyone know the outcome there would be of a "tactical" deployment of "armed struggle" by the IRA to "nudge" things along.
Neither, of course, do we know what the outcome would be of David Trimble being coerced into an executive or indeed to David Trimble joining an executive now in defiance of his repeated undertakings not to do so without a start to decommissioning.
Decommissioning essentially is a synonym for unionist apprehension over the authenticity of Sinn Fein's commitment to peace. In itself decommissioning doesn't amount to much, for who could say that a start to decommissioning would mean there would be a continuation of it? What matters is the genuineness of the republican movement's commitment to peace.
That can be established by mechanisms other than decommissioning, or at least it can be indicated.
The most important indication is the absence of violence, and the reality is that the war has been over since July 1997: 21 months. This is not a long time admittedly, especially given that the last IRA ceasefire broke down after 18 months.
But the absence of war is in itself a reassurance, though hardly enough, given what went on for 24 years. The best reassurance is how the republican movement has locked itself into this peace agreement. It accepted the principle of consent, in contradiction to what it said it had been fighting for for over a quarter of a century. It agreed to participate in new governmental structures and to make them work.
But obviously this is not enough reassurance.
What might work would be the following.
First, an unequivocal statement by the leadership of Sinn Fein (and, clearly, that should do, given that the unionists believe that the leadership of Sinn Fein and the IRA are the same thing) that the war was over.
Yes, Gerry Adams said something like this a few months ago but there was a qualification in what he said: he said he hoped this would be so. Now let him say it without the qualification and let him say it explicitly in response to the understandable anxieties of unionists.
Second, a statement by the British and Irish governments and the SDLP, saying that if it ever emerged that the associates of Sinn Fein were engaged in war in any sense, or were preparing for war, then they would all move to have Sinn Fein excluded from the executive forthwith.
But one way or another the current impasse cannot be allowed to persist. We cannot afford the disappointment of our current hopes.