Like the poor, decommissioning is always with us. This reporter was chatting to a senior loyalist politician at Stormont yesterday when another senior loyalist approached. Without even being told, he knew we were talking about the D-word.
Even Clinton jokes take second place to decommissioning as a topic of conversation here. There is a sense of gradually building towards a crisis, with the usual uncertainty about getting through to the other side of it in one piece.
Senior Northern Ireland Office figures were philosophical. True, Mr Trimble and Mr Adams were "hardballing" on the issue, but that was always going to happen. Accentuate the positive was the feisty message from NIO insiders: at least Mr Trimble and Mr Adams were now meeting face to face and in private. This, allied with all the other developments, such as the reduction in troop levels and the release of prisoners, amounted to a series of plus-points and reasons to be cheerful.
By contrast, dissidents inside the Ulster Unionist Party struck an ominous note. As they saw it, the choreography was being devised, by the two governments and others, for leading the parties towards another fudge. If that happened, the dissidents warned, there would be hell to pay inside the UUP.
Senior loyalists were categorical: decommissioning wasn't on. The same message came from senior republicans. But UUP leadership sources were flatly insisting that it must happen.
It is understood Sinn Fein could live with a statement from Gen de Chastelain asserting his confidence that all parties to the process were genuine and sincere in their efforts to achieve decommissioning within the agreed two-year period. But the UUP wants "product", whether it is left outside the gates of Stormont, blown up under supervision in a country field or handed in at a police station on either side of the Border.
Thus we have reached a classic impasse. Senior unionists were insisting that Mr Trimble had not retreated from a demand for immediate "hardware" to the more measured position of wanting to know when that hardware would be forthcoming. Sinn Fein said it could deliver neither, but the change in Mr Trimble's language can hardly have escaped the party's notice.
Publicly, however, Sinn Fein was expressing concern about Mr Trimble's suggestions that (a) the executive could be formed without Sinn Fein, and (b) prisoner releases should be slowed down.
Despite its public tut-tutting, Sinn Fein must know as well as the rest of us that forming an executive without it is not politically possible for the SDLP, even if the main nationalist party wished to be involved in such an enterprise. The release of prisoners is proceeding and, realistically, the only way it can be halted or delayed is if some paramilitary, intoxicated by his new-found freedom, perpetrates a very serious crime which shocks Northern Ireland.
Nevertheless, it is smart politics for Mr Trimble to make a fuss about issues that are disturbing the peace of mind of ordinary unionists at the moment. It is equally clever of Sinn Fein to be publicly appalled by Mr Trimble's comments on these issues, rather than adverting to the possibility of a change of tack by the UUP leader on the core issue of guns on the table.
"It's no longer a question of if decommissioning is going to take place, it's a question of when," chimed Dr Mo Mowlam after her meeting with the Taoiseach in Dublin.
This new focus on the timing for the handover or supervised destruction of arms may yield a solution to the current imbroglio. Mr Ahern is at his best in these last-minute negotiations where he can draw on his years of experience as an industrial mediator, narrowing down the differences and striking a deal which leaves both parties more or less satisfied.
Even NIO sources were adamant that the removal of troops from Belfast's streets and the scaling down of the overall British army presence were elements of the agreement which must be implemented regardless of progress on decommissioning. Thus it would be wrong-headed to expect that even the dismantling of British army bases in south Armagh would lead to reciprocal gestures on weapons from the IRA.
What is required, according to republican sources, is movement all across the board. Republican activists have what one source called a "show me the money" attitude. The major institution set up under the agreement so far is the Northern Ireland Assembly, which is seen by republicans as a concession to unionists. Until republicans see the establishment of the North-South bodies with Sinn Fein ministers taking part, as well as the implementation of other aspects of the agreement, there is little hope they will even start to consider handing over or otherwise disposing of arms.
In retrospect, nationalist negotiators may feel they made a mistake in the talks by not pinning down the terms of the agreement to a more precise timetable for the formation of the "shadow" executive. In this context, the only relevant date in the agreement is the October 31st deadline for identifying and agreeing areas for North-South co-operation.
In principle, this decommissioning saga could drag on into the new year and might even delay the formal transfer of powers to the Assembly, which was originally expected to take place in early February.
Inevitably, much of the burden of resolving the impasse is falling on the two governments. Dublin has been at the end of its tether trying to come up with a formula. Republicans claim London has not been jogging Mr Trimble's elbow enough of late.
There is a note emerging from Sinn Fein quarters recently which betrays a feeling that they have been taken for granted. As far as they are concerned, they moved mountains by persuading their followers and associates that non-violence was the best option. At the same time, in the Sinn Fein worldview, the unionists were sitting on their hands and refusing to budge.
This perspective is somewhat unfair to unionists. For example, who could have imagined a unionist leader, even two months ago, daring to hold private conversations with the political leader of Irish republicanism?
Mr Adams refused to be drawn yesterday on whether he had initiated a telephone call to Mr Blair. "We phoned each other," he quipped. But coming so soon after his conversation with Mr Trimble, it may well be that the Sinn Fein leader was appealing to the Prime Minister to step in, exert his authority and prevent a drama turning into a crisis.
By all accounts, Mr Blair and Mr Trimble are close and get on well, so the Prime Minister will be reluctant to twist the UUP leader's arm. At the same time, the prospect of appearing before next week's Labour gathering in Blackpool with a freshly minted solution to a seemingly insoluble problem must have considerable appeal to Mr Blair.
He went very far out on a limb to reassure unionists on decommissioning before the May referendum. Now he has to come up with a down-to-earth solution which, in the nature of all compromises, will leave nobody completely happy. Politics is the art of the possible, but how good an artist is Mr Blair?