THE IRA, in typically ruthless fashion, has demonstrated that it runs its own agenda - and that agenda is remorseless war until its enemies agree, genuinely, to sue for peace.
Its pursuit of this path has left Sinn Fein neutered and confounded, its political credibility collapsing and its leaders casting about desperately for ways to reassemble the pan nationalist upon which they had placed so much hope.
In this scenario Mr Gerry Adams finds himself cast in a Humpty Dumpty rescue role. The plain reality is, however, that there is no way that he alone can put the pieces back together.
All of his formidable dialectical skills and personal resilience are already under enormous strain as the situation builds. His task is magnified enormously by the inevitable spread of insidious conspiracy theories, doubts and uncertainties all occasioned by the implacable secrecy and unaccountability of the faceless cabal known as the IRA Army Council.
A leading republican admitted in a private conversation last year that his organisation could not identify with certainty who really controls British policy on Ireland. That was the reason, in the end, that the prolonged secret contacts between British intelligence emissaries and the IRA broke down.
Equally clearly, now, neither the British nor anybody else know who really runs IRA policy and whether or not Sinn Fein has any meaningful influence on it.
For several years now, the development of Sinn Fein into a sophisticated political machine, with an increasingly accessible public persona, has led governments and public alike to develop a "working assumption" that the party represented an accountable core of republicanism that could be engaged with on a businesslike basis.
This was certainly true, within limits which have now been exposed. Mr Adams and a number of his senior colleagues spoke authoritatively and readily, and offered a reasoned exposition of the concerns, the needs and the aspirations of the broad republican community which they represent and which plainly endorsed their leadership.
Most people remained acutely aware that a tail was still attached somewhere to the dog, but they had begun to assume that it was merely a necessary, but non vital, appendage.
On Friday night, the tail wagged with a vengeance, forcing people once again to regard the animal as a whole. For the political leaders (not including the unionists and only half heartedly including some levels of the British establishment) who aspired to do business with Sinn Fein, the party's relationship with the IRA has again become a major issue.
Just as republican representatives finally discovered that the British emissaries they talked to could not, in the end, be accepted as speaking directly and authoritatively on behalf of the British government, those who have been speaking to Mr Adams now find themselves in a similar quandary.
There is considerable force in the argument that things might have been different if the principal figures on both sides (at least, those who were publicly seen as the principals) had got together. If the British Prime Minister, Mr John Major, had engaged directly with Mr Adams, the capacity of each to deliver a genuine deal would at least have been tested.
Now, as the fall out from the London bombing settles on Mr Adams's broad shoulders he has also been undermined by his own side. In effect, the IRA has enacted a military coup on the republican political establishment.
That may please elements of Mr Major's government as well as the unionists, but their more serious political advisers and assessors are probably privately aghast already at the chaotic prospect it unfolds.
In the republican arena Mr Adams - with the assistance of Mr John Hume and Mr Albert Reynolds - demonstrated that he could deliver the goods primarily desired by everybody: a prolonged, open ended ceasefire.
He complained yesterday, with considerable justification, that he was then left in the lurch - with everybody from President Clinton to John Major to the European Commission climbing on the bandwagon of a qualified cessation of violence that crucially required the cement of political accord to build it into permanent peace.
Senator George Mitchell, late in the day, offered a formula by which the possibility of deconstruction of the military paraphernalia of the IRA (and, by extension, of the IRA itself) could at least have been tested. That, however, was not to be, and now John Major has found himself at the wrong end of the dog.
If the worst happens, and conflict escalates, he may have to deal with a new quantity - a devil he does not know. Mr Adams's credibility has now been thrown into question, not just among outsiders, but in certain republican quarters also.
People are asking, half openly, if there is a conspiracy to depose or demote him. If not, how could it be that he could have been kept unaware - at least in general terms - of the Army Council's drastic intentions? Could it be that he did know, and opposed them, and was overruled and now must make the best of it? These hypotheses and questions, however wild, will generate uncertainty and confusion while they remain unanswered.
The wide consensus of opinion in political circles for the moment is that the Sinn Fein president was genuinely kept in the dark. That still leaves many disturbing questions and gravely damages his effectiveness and authority at the high political levels where he has come to command great influence.
Mr Adams's status in the republican community at large, however, is so high that it is questionable whether the IRA could sideline him and still hope to continue to operate as freely as before.
As British analysts have acknowledged, the IRA's effectiveness has depended heavily upon an uneasy sufferance of its activities by the communities among and within which it operates - in other words, that ordinary people should continue to turn a blind eye.
That sufferance has, in turn, only persisted because of the repressive presence and activities of a massive British military machine, an armed and unaccepted RUC and - most crucially - the perceived threat of loyalist sectarian attacks.
The attitude of ordinary people to the IRA has already been shaken severely by the merciless punishment beatings and shootings of alleged drug dealers. In spite of the cruel sanctions it has available and has readily employed, it could hardly risk an open manifestation of contempt for the Sinn Fein representatives and councillors who live and work in the midst of the communities.
But the IRA, almost certainly, has also calculated that Sinn Fein has no alternative but to continue trying to rationalise and justify whatever military type operations are mounted. Or, rather, that any other course by Mr Adams and his colleagues would almost certainly generate that worst of all scenarios for republicans - a bitter split in the movement.
Aware that the Sinn Fein leadership could not risk such a disastrous development, the militarists within the IRA's highest ranks will continue to hold the whip hand over both strategy and tactics.
What seems inevitably in prospect is a renewed and bloody clash of wills between them and the very highest ranks of British political power, with the ordinary nationalist people - and now also Sinn Fein and the British public caught in between.
This is the "eyeball to eyeball" confrontation so vividly warned of by the Sinn Fein president a year ago and recalled by him grimly yesterday. Could it be, in the irony of history, that Mr Adams will turn out to have been the greatest asset that the British Prime Minister never had?