Is David Trimble bluffing? Would the First Minister Designate really see the Belfast Agreement collapse on the issue of IRA decommissioning? And, if push came to shove, would the two governments choose "the political process" or "the peace"?
We may be sure Mr Ahern and Mr Blair have no disposition to have the questions and choices confronting them rehearsed or defined in such terms. Indeed one can imagine Mo Mowlam's disdainful dismissal of such a line of questioning.
With a good deal of justification, the Secretary of State would scorn the sceptic with the evidence of the amazing progress already made against the general expectation. She knows, too, that the crucial compromises and accommodations at the heart of the Belfast Agreement were struck by politicians who seem to find liberation only in the looming deadline, the pressure-cooker of the late-night negotiation, and after a ritual glance over the edge of the abyss.
As it was before, so Dr Mowlam hopes it will prove again. Battling to give the process momentum, she has called "the finishing line" into view and proclaimed March 10th "Devolution Day". Her projected timetable sets out clearly and simply the steps necessary to prepare the way for the creation of the shadow executive and the consequent transfer of power to the Assembly. However, as she and the parties are acutely aware, it also clears the way for a showdown on the one issue which retains the capacity to derail the entire process.
The hope that that showdown could be avoided has nose-dived, if not altogether disappeared, this weekend. Following through the logic of his previously declared position, Mr Trimble has made his intentions quite explicit. If IRA decommissioning has not started at the point of the formal transfer of powers, he will seek Sinn Fein's exclusion from the executive and will also seek to have the entire process "parked".
Gerry Adams's response was swift and direct. If Mr Trimble was serious, he said, he "should do the decent thing and resign now".
The eternal optimists will argue that this is how a negotiation works. And time may again prove them right. But there are many others, including dedicated supporters of the agreement, who fear the brinkmanship carried to the point where it is hard to see how either man might move without incurring serious, and possibly fatal, political costs.
Certainly it is hard to see how Mr Trimble could effect a U-turn now, even if he wished. Moreover, and this would seem to be the crucial point, all the evidence is that he does not so wish.
True, he has surprised before. And some of his "rejectionist" critics believe, or at any rate maintain, he will abandon his position when confronted with the British and Irish government view, and at core it is their view, that IRA decommissioning is not a precondition to Sinn Fein's entry to the executive.
Jeffrey Donaldson last week warned the Ulster Unionist Party would "fall apart" if it entered into the executive with Sinn Fein without its decommissioning demand being met. Trimble loyalists, however, have always insisted it would never come to that. As early as last June, in the middle of the Assembly election, Reg Empey dismissed this journalist's inquiries about the likely breaking point within the UUP Assembly party.
Yes, he acknowledged, there would be intransigence in the Assembly party on the arms issue. The mistake was to assume people like him would not be part of it. Unconvinced that the war really was over, Mr Empey insisted Sinn Fein would not gain entry to government until the IRA paid the price.
Mr Empey would doubtless say it is his line, and not that of Mr Donaldson, which has held. And it has been echoed in the last few days by Mr Trimble's assertion that he believes he has taken the process as far as he can.
That is made explicit, too, in the "background briefing note" circulated by his office on Friday night. The document says that by March 10th, when the Privy Council is due to meet, the UUP "will have discharged all its obligations under the Agreement needed to form an executive".
Without "a credible start made" to decommissioning, the document makes clear, the UUP "will move to exclude" Sinn Fein from the d'Hondt process for the allocation of ministerial posts. And it asserts: "David Trimble will have taken the unionist people farther towards partnership government and lasting peace with their nationalist neighbours than any other unionist leader this century. He must therefore have reciprocation if he is to continue to bring unionism with him. He must be given credit for what he has done."
In a clear attempt to stay Dr Mowlam's hand, the note also warns that any attempt by her to establish the executive without decommissioning "will undoubtedly blow the Agreement and all the progress we have made to pieces". In a further elaboration of his thinking on Saturday, Mr Trimble told the BBC's Inside Politics programme he would seek to ensure "a soft landing" for the process, by which he seems to envisage a return to negotiation mode for the duration of a protracted standoff, at the end of which the IRA will be forced to concede.
But what if it does not? The Ulster Unionist Party leader is hardly blind to the dangers ahead. With their tails briefly up during the early stage of last year's referendum campaign, Mr Trimble and his colleagues actually told unionists the one guaranteed way to ensure no decommissioning was to bring down the agreement.
They seemingly found no merit in Seamus Mallon's guarantee to support Sinn Fein's exclusion if the IRA had not decommissioned at the end of the two-year period. And they are hardly unaware that some republicans might actually calculate benefit and potential in Mr Trimble's fall, and the disarray and division, revisions and realignments within unionism which would inevitably result.
Mr Trimble will also know that many will readily blame him for any failure; that failure would inflame the natural antipathy of many on Mr Blair's back benches to unionism generally; and that in any event, given the disposition of both governments and the expectations of the broad nationalist community, the failure of this "solution" would ultimately mean only that the quest for a solution would go on.
The UUP leader has not addressed these questions, and the hope will be that he never has to. Indeed, some will dismiss such bothersome speculation, confident in the belief that ambition and the judgment of history, the investment already made and the absence of any obvious alternative will eventually dictate a compromise.
Yet David Trimble has struck many as a curiously "unpolitical" sort of politician. Over dinner, just a short time after his election, it was startling to hear him speculate about the point at which he might vacate the recently-acquired leadership. Not for him the long years of Jim Molyneaux's rule, he vowed; there was a life beyond politics, a sentiment to which he gave voice again during a recent Channel 4 documentary. Might he conceivably be embracing it sooner than even he would have anticipated?
Mr Trimble shows no willingness to countenance the possibility. He remains insistent that the IRA will decommission, because the republican movement in his view has no alternative, and that he will be leading a fully-inclusive power-sharing administration later this year.
Nor, of course, does he accept that, should he be wrong, the exclusion of Sinn Fein would mean the end of the line. The briefing note spells out the expectation that, if there is no decommissioning, the Northern Ireland Office and the SDLP "will co-operate" with the UUP "to achieve a safe way forward for the political process".
This has been a recurring UUP theme. But its constant repetition does not make its achievement any the more likely. Sinn Fein sources dismiss the possibility out of hand. "If the agreement is not up and running by May then you have no agreement" is the straightforward view of one insider.
Whatever the argument about precisely how long the agreement could endure the standoff, few would disagree with his general sentiment. Few, either, believe that, short of the IRA resuming its war, there is any serious possibility of the SDLP entering the executive without Sinn Fein.
If the reality is that Mr Trimble is not bluffing, this is the other reality with which he and his party have still to contend. Both governments remain determined that a way through the impasse can be found and are doubtless bending their energies to that end. They will also be aware that, far from threatening six or seven weeks down the line, the crisis is upon them.
