To the casual observer or even those who should know better the current difficulties in the Irish peace process appear simple enough. It is all down to why the IRA has not decommissioned by now. This has been the hypnotic, all-pervasive drumbeat now rising to deafening loudness and drowning out all other logic.

As everyone knows, in the review of the process, chaired by Senator George Mitchell, certain agreements were made which led to an unprecedented move by the IRA to engage with the Independent International Commission on Decommissioning, and the Ulster Unionist Party participating in institutions which they had boycotted since the Good Friday agreement in May 1998.

The Mitchell review was actually set up because the unionists, in a bizarre but successful attempt to face down the British government, boycotted the new Assembly in July last year when London triggered the mechanism by which ministers could be appointed. By their actions and their rejection of what was a Sinn Fein initiative the unionists successfully scuttled yet another effort by us and others to implement the Good Friday agreement.

It is not surprising therefore that there was a huge welcome when, as a result of the Mitchell review, the unionists were eventually persuaded, 18 months late, to go into the institutions. David Trimble did the right thing. But as always, like the cow that gives the good milk and then kicks over the bucket, the UUP, at the last minute, and totally outside the terms of the Mitchell review, announced its own unilateral deadline for IRA disarmament.

So what's it all about? There are undoubtedly problems within unionism, which finds it difficult to come to terms with the changes that are required if the Good Friday agreement is to become a reality and if a transformation of the political landscape here is to be achieved.

Some of those within unionist activism have opted for the rejectionist anti-agreement demand for the Good Friday agreement to be scrapped. These include the DUP which, despite its rhetoric of outright opposition, has none the less taken up ministries and committee chairs and is working within the Assembly and the institutions and with the other pro-agreement parties.

The anti-agreement clique also includes elements within Mr Trimble's UUP. In my opinion, and despite the opposition within his own party, David Trimble's leadership would have won majority support in the UUP for participation in the institutions at any time in the last 18 months if he had put such a proposition.

The truth is David Trimble never put such a proposition because his tactical approach to the agreement, unlike the rejectionists, was to constantly renegotiate it, to whittle it down, to minimise and to protract the process. It wasn't Sinn Fein which persuaded the UUP leadership to enter into the institutions in December. We tried and failed. It was the British government, and particularly Peter Mandelson, which persuaded the UUP leadership to do the right thing.

On Remembrance Sunday weekend, at the end of the Mitchell review, Mr Mandelson conducted an intensive lobby of the UUP. This followed the rejection by David Trimble of propositions contained in the Mitchell review.

The result of this work, and of persuasive arguments by others, including President Bill Clinton, was that the institutions came to life. Now Mr Trimble is saying that Sinn Fein is in default of that review because the IRA did not decommission by January 31st.

Mr Trimble is wrong and he knows it. I can provide chapter and verse of the detail of Sinn Fein's position and it is the same position we have argued publicly and privately with successive British and Irish governments and others, including the unionists, for almost as long as I can remember. So, I repudiate absolutely any accusation of bad faith by us. On the contrary, we acted in good faith and we continue to do so.

Even now at the time of writing, as Mr Trimble threatens to resign his position unless the British government pulls down the institutions, Sinn Fein is working away trying to save the process. We are in intensive discussions with all sides to avert disaster. In my view the whole issue of arms can be satisfactorily resolved and I am committed to resolving it. But proving that politics does not work is not the way to persuade armed groups. In other words this issue can be resolved and in my view will be resolved but only if all play their part in a constructive and positive way.

The IRA cessation has lasted five years. At that time the UUP leader, James Molyneaux, described it as the most destabilising thing to have taken place in 70 years. The demand for decommissioning came after this cessation and was no part of it. It has been used to cripple and retard, and may indeed eventually hole this process below the water line.

Of course it would be simpler if armed groups would just do what is demanded of them, but it was never going to be that easy. Yet there are positives. On Tuesday the IRA, in an effort to reassure unionism, said that it was committed to the peace process and that there was no threat to the process from it.

So guns that are silent, that are out of commission for five years, which belong to an organisation whose representative is engaged with the decommissioning body, are going to be the reason or the excuse to tear down institutions which are barely eight weeks old. Why?

Could it be that this is not about decommissioning at all?

Could it be that the unionists want a different agreement? That they imagine they have some shortterm advantage over Sinn Fein? That they can bring down this agreement and renegotiate another one more satisfactory and acceptable to them? Could it be Peter Mandelson will facilitate them in this?

One thing is certain: within the next 24 hours or so the process can be saved. The de Chastelain report - essentially a progress report - will be published by then. There is no reason why it cannot be a positive report and why it cannot be taken up positively by the British government and by the UUP. That way the full implementation of all aspects of the agreement is guaranteed.

There's another thing for certain. If the unionist game plan spooks the British government into suspending or collapsing the institutions - and there is no difference between suspending and collapsing - then like Humpty-Dumpty all of this will be very difficult to put together again, and decommissioning, which the unionists make such a great fuss about, is unlikely ever to be achieved.

Some political leaders see this peace process as about winners and losers. There will be no winners, and the only losers will be the plain people of Ireland and our friends and supporters throughout the world. I say there will be no winners. That's wrong. Because of course the anti-agreement clique, those who are against the change, the reactionary bigots, will have succeeded in dragging unionism back to their agenda.