Donald Macintyre: Now the IRA must show that it means business

'What is needed is some concrete sign of good faith beyond inspections on the decommissioning of arms'

Wearily, warily, and with virtually no hope of some dramatic 11th-hour breakthrough, Tony Blair and the Irish Taoiseach fly to Belfast once more today. The marching season looms, with the annual stand-off at Drumcree only 10 days away. Ugly street violence continues to flare between Catholics and Protestants in north Belfast and elsewhere. And now it seems inevitable that all this will take place in the shadow of a political event whose significance it would be dangerous to underestimate: the resignation, this weekend, as First Minister of David Trimble, the architect of the peace process on the Unionist side, and one of that small, select group without whom a lasting political settlement for Northern Ireland would never even have been in sight.

No one now seriously believes this won't happen. Officials caution against expecting some make or break moment of the sort that has happened so often in the past, and speak only of the high-profile prime ministerial visit being to "initiate a talks process" which will continue into next week. Indeed it is even possible that the Northern Ireland institutions could unravel a good deal faster than it seemed even a week ago.

It has hitherto been thought that Mr Trimble's resignation would leave a breathing space of six weeks, the period allotted by the Northern Ireland Act under which the assembly can try to agree on the appointment of a successor. There have now been ominous hints that Mr Trimble's resignation could be followed after a short period by other unionist ministers, thus collapsing the executive altogether, which would begin to make suspension of the institutions by the Northern Ireland Secretary – the second in 16 months – a distinct possibility. The difference then was that the suspension prevented Mr Trimble's resignation. This time, barring a miracle, nothing looks capable of preventing it.

Nor is Mr Trimble likely to go gently into that good night. He doesn't want to go, but he is unlikely to mince his words when he does. He is angry with many people, the British government included, for leaving him to take the heat and make the leaps of faith so often in the past. But he will surely reserve his strongest words for the republicans for failing to carry out what he was persuaded in May last year was a firm commitment to start putting their arms "beyond use".

And he will be right. The time to mince words has long past. For all the logic-chopping from Sinn Fein about the British Government failing to fulfil every dot and comma of their obligations under the agreement, the republicans have made enormous, tangible gains since the Good Friday Agreement of 1998.

The once unimaginable prospect of two Sinn Fein ministers sitting in government with the other parties has come to pass. IRA prisoners have been released from jail in their hundreds long before their sentences were completed. Not only has British Army patrolling been significantly reduced, but 40 per cent of army bases have been closed. And whatever the detailed complaints by republicans about the implementation of the Patten report, there has been dramatic reform of policing that has already seen a significant increase in Catholic recruits and would see an even more significant one if Sinn Fein and the nationalist SDLP did not continue to withhold their backing. In return, not a single rusty revolver, let alone the huge and sophisticated arms cache held by the IRA, has been decommissioned. What's more, every party, including the British government, has made it clear that further concessions are possible – but only if the IRA starts to fulfil its part of the bargain. This is why there has never been more unanimity, across a spectrum including the Irish government, the Dublin press and all the sane parts of Irish America, that it is now the IRA's turn.

Whether the IRA will see it that way in the coming tense and difficult weeks remains to be seen. I may have been over-optimistic to the point of naivety when I wrote last week that the logic of the republicans' position would surely save the political process. It's entirely true that if Sinn Fein are to build on their electoral success to the point of being brought into coalition government in the Irish Republic, on the strength of, say, six or seven seats in the next general election there, they will have to disarm.

It is also true that their gains in Northern Ireland – where the Sinn Fein-voting nationalist youth is about the only socio-political group in the UK increasing its turn-out – have given them a huge mandate to face down their own militarists and do just that. And it is true that they cannot ideally want to collapse a Northern Ireland executive in which they have two prominent ministers.

But Sinn Fein's electoral success unfortunately cuts both ways. It also proves that you can win elections without decommissioning arms; that the Armalite, provided at least that it is silent, can still combine with the ballot box – especially if helped here and there by a little good old-fashioned intimidation. And if, as some observers believe, the republicans' strategy is not actually to get into government in the Irish Republic in the short to medium term but simply to gain seats, then it may well be able to do so without much significance in the way of putting arms beyond use. Indeed, one fear is that the republicans would actually like a temporary dissolution of the assembly so that the Secretary of State is impelled to call elections and they can consolidate their strength in the assembly as they did in the Westminster elections – a prospect which makes suspension of the executive an altogether more attractive proposition.

For which, if it happens, the IRA/Sinn Fein should, and surely will, take the blame, internationally as well as in Northern Ireland. There is actually considerable legalistic confusion over the exact period which would follow Mr Trimble's resignation and in which further negotiations can take place.

But given that Mr Trimble has publicly referred to the breathing space after he goes, it would be odd if his colleagues quickly walked out too and precipitated even more of a crisis than there will, in any case, be. The conventional view is that talks could go on until mid-August; on the other hand, the fact that the assembly's summer recess is imminent could just possibly prolong it further. But that doesn't alter the basic question: is the IRA ready to play its part in keeping the agreement on the road?

The fact that Sinn Fein complains that the British government has "only" implemented about 90 per cent of the Patten report, or that, faced with a powerful and active threat from the Real IRA, the Army isn't prepared to dismantle every installation in South Armagh should be seen, at last, in context. Not only is further movement possible on these points if, and only if, the IRA plays its part, but nobody is actually expecting it to decommission 100 per cent of its arms. What is needed is some concrete sign of good faith beyond inspections that they mean business about decommissioning. In the past it has been the IRA's habit under maximum pressure to produce the minimum required. There is no sign as yet that they are even prepared to do that. And if they are not, let the full obloquy that they deserve, international as well as national, fall on them.

d.macintyre@independent.co.uk