Why do most of the parties to the Belfast Agreement speak and behave as though the calendar were stuck at April 9th, 1998? Nine months ago, the world stopped to wonder at the achievement of Good Friday.
After several days in the hothouse of negotiation, the parties emerged into the light to announce, to a sustained fanfare, that an agreement had been reached and was about to be signed.
With the exception of the usual unionist rump, none of those involved gave the slightest impression - by, for example, refusing the acclaim of the watching world - that the agreement was conditional or half-baked. It was, we were told, a "historic" agreement, which was taken to mean a previously unimagined breakthrough in the conflict.
Nine months later, it appears the leader of the Ulster Unionist Party is unaware of the content of the agreement he signed. Repeatedly, in interviews and statements, Mr David Trimble interprets the agreement in contradiction of the document itself. More worryingly, he does this without serious objection from most of the other parties to the agreement.
Last week, for example, Mr Trimble said that if the IRA did not hand over its weapons, the executive could be formed without Sinn Fein, which would have to remain in "opposition" until decommissioning is achieved.
Mr Trimble explained he did not believe Sinn Fein had "tried its hardest" to get the IRA to disarm. "Either they haven't used their best efforts or these have proved fruitless, and I don't think anyone believes the latter," he said.
Mr Trimble also said he welcomed a recent article written for two Belfast morning newspapers by the British Prime Minister, in which Mr Blair described decommissioning as a "key confidence-building step".
What Mr Blair writes in newspaper articles may be interesting, or elucidatory, or even occasionally helpful in persuading one or other of the parties to go a little further down the road, and such statements should, of course, be given full consideration by all parties. But they cannot, any more than IRA statements, be considered part of the Belfast Agreement.
The Belfast Agreement makes no mention of "confidence-building steps". What it says in relation to decommissioning is: "All participants accordingly reaffirm their commitments to the total disarmament of all paramilitary organisations. They also confirm their intention to continue to work constructively and in good faith with the Independent Commission, and to use any influence they may have, to achieve the decommissioning of all paramilitary arms within two years following endorsement in referendums North and South of the agreement and in the context of the overall settlement".
Mr Trimble may be right in suggesting that Sinn Fein's efforts to persuade the IRA have not been vigorous enough. But it is unclear what this has to do with the content of the Belfast Agreement, which makes no provision for any definitive judgment on decommissioning before May 23rd, 2000. Also, the agreement most certainly does not allow for conclusive judgment on this issue in advance of the setting up of the executive.
Why, now, does Mr Trimble pretend not to understand the agreement he signed up to last April? (And why, incidentally, when such statements of his are reported in the media, is Mr Trimble invariably described as "First Minister", when he has not the authority to make such statements in this capacity?)
And why do the Taoiseach and the Prime Minister, instead of telling Mr Trimble to go home and study the agreement, repeatedly create further confusion by implying Mr Trimble may be right?
Mr Blair has several times made statements which, for all their good intentions, have fed the Ulster Unionist Party's attempt to rewrite the agreement.
But at least Mr Blair has been consistent, which cannot be said of Mr Ahern, who has in recent months said that the IRA should decommission; the IRA should express support for decommissioning within two years; we shouldn't get bogged down in the decommissioning issue; republicans had more room for compromise than Mr Trimble; decommissioning was never meant to be a precondition of Sinn Fein's participation in the executive; there is unlikely to be decommissioning "in the immediate future"; he could not see an executive being formed in the absence of decommissioning; the executive would have to be formed before decommissioning could begin; the Government would insist on the agreement being adhered to and that Sinn Fein was complying fully with its obligations.
If you can work out what the Taoiseach thinks from this list of highlights of his pronouncements, your name is probably Martin Mansergh.
Two reasons are advanced to justify the continuing high tolerance of Mr Trimble's antics. One is that decommissioning is central to the spirit of the agreement, which seeks to replace war with politics. Thus, the argument goes, careful scrutiny of the letter of the agreement, and a literal approach to what it says, are arid and futile. This is a persuasive argument, in as far as it is true that the spirit of the agreement clearly envisages decommissioning at some stage.
But it is also true that the spirit of the agreement, as well as the letter of the document, proposes a strategy whereby this objective might be achieved, and that this involves a complex, interlocking mechanism which allows for progress in various areas to be made in a series of steps - thus the phrase "in the context of the overall settlement".
In other words, the logic of the agreement, both in word and spirit, is that the entire apparatus of the process, including the decommissioning aspect, is predicated on the detail of the agreement being implemented to the letter. That is why the agreement took so long to negotiate. It is also, presumably, why it was met so euphorically.
The other argument for indulging David Trimble has to do with what is called the realpolitik of his position, by which is meant the presence of a rump of disgruntled grassroots party members waiting to swoop if he "gives in".
Even if this were a real possibility, it is not a reason for rewriting the agreement, which is a solemn undertaking by a majority of the people of this island to move forward in peace. Are we to allow the agreement to fall in order to protect Mr Trimble's position as leader of the UUP; and, if so, why?
The time for thinking about realpolitik was in the early hours of last Good Friday morning. It is Mr Trimble's job as a political leader to lead his own people along the road he has embarked upon. By signing the agreement, he committed himself, his party and its followers to a specific course, and he should either stick to that course or leave politics, hand back the £300,000 peace prize and go off to grow chrysanthemums.
