The choice weighed heavily with the UUP man. A Trimble loyalist and a firm supporter of the Belfast Agreement, he also unhappily had believed the party's "no guns, no government" policy had meant precisely that.
There was real agony in the indecision. "I don't know, I just don't know," he sighed. "If I believe Adams and McGuinness, then it's good. In fact the stuff in the Sinn Fein statement would be very good indeed. If I was convinced about them, then we really could have a deal. I don't know. We're that close, it's just a millimetre away. Yet in the end it could as easily be a mile."
Mr Trimble's friend knew which side he had to be on. He cordially detests his party's leading rejectionists and could never contemplate making common cause with them. He'd sooner leave the party and quit politics altogether, but his heart wasn't in it. He feared the republican talent to use language as a substitute for movement.
He had wanted sight of that first delivery date. He knew it wasn't there. Hell, in truth there wasn't even the firm promise of it. And he sensed that the delegates to the Ulster Unionist Council - plain-speaking, literal-minded folk - would not be prepared to take decommissioning on trust.
For all that, when the collection of the heads finally came on Thursday, he gave Mr Trimble the nod. Despite an extraordinary display of evasion and disinformation later that night, The Irish Times established that a clear majority of Mr Trimble's colleagues had similarly obliged.
As seven or eight Assembly members ruefully shook their heads, Mr Trimble doubtless wondered which of them he could gladly live without and which of them he might hive off further down the line. But there was one without whom Mr Trimble had decided he would not travel. For the moment at least, Mr John Taylor's Nay had clinched it.
Mr Taylor, still notionally Mr Trimble's deputy, had been kept in constant touch with developments as the negotiation with Sinn Fein progressed. And an article in the Belfast News Letter earlier in the week insisting that the IRA would have to endorse any Sinn Fein position emerging from the review was eagerly seized upon by British government officials as evidence that the Strangford MP was back on-side.
There was altogether less certainty on Wednesday night, when Mr Taylor missed his flight and failed to reach Belfast as expected. When the meeting with Mr Trimble finally took place on Thursday morning, Mr Taylor bluntly told him the deal was not acceptable and any attempt to force it through would tear the party apart.
Much merriment attends Mr Taylor and the famous "barge pole" with which he has, from time to time, assessed the improving or faltering prospects for agreement. He is not revered among colleagues as a model of consistency and has doubtless used the barge pole on occasion as an instrument of tactical evasion. Seasoned correspondents certainly know he is not always to be taken at face value and that sometimes he quite simply enjoys the sport.
However, there has in fact been a consistent and deadly serious theme to Mr Taylor's analysis of the unfolding political situation in Northern Ireland since at least the early summer. Nor has he made any secret of it.
Simply put, Mr Taylor concluded some time ago that the Belfast Agreement could not work; that the IRA had no intention of decommissioning; that without it the Ulster Unionists could not break their manifesto pledge and enter government with Sinn Fein; and that any decision by Mr Trimble to do so, under pressure from the British government, would take the UUP on to the rocks.
John Taylor, the great survivor of unionist politics, has vivid recall of the events which saw the once-monolithic Glengall Street machine shattered on the rock of Sunningdale. He has told friends he would not be prepared to see the party torn and divided in that way again. They in turn credit him (like others such as Ken Maginnis and Lord Molyneaux) with "a sense of party" they suspect Mr Trimble has never altogether shared.
There now seems little doubt that Mr Trimble is prepared to see his party split, and seriously, in his quest to save the Good Friday accord. Having concluded his negotiation with Sinn Fein under Senator Mitchell's chairmanship, that is unquestionably what the British and Irish governments expect of him.
Almost certainly yesterday's brief adjournment of the review - before the now inevitable conclusion one way or the other - is about one thing: giving Mr Trimble time to make up his mind to do it. Senior unionists on both sides of the argument suspect his decision is already made, and expect the party's ruling council to meet in emergency session within two weeks.
Some well-meaning supporters will be urging him on, telling him he has nothing to lose in any event; the "back-me-or-sack-me" tendency augmenting their case with the assurance (dangerously tempting in the case of Mr Trimble) that, should he fail, there is a life beyond politics.
However, the fact of his slightly semidetached relationship with Ulster Unionism does not mean Mr Trimble is without his own "sense of party". It is unlikely he would see the UUP implode just for the hell of it, or in some brave-if-doomed act of personal justification. Mr Trimble's cool calculation will be whether he can incur the split and survive it to purpose and effect.
That means not simply winning a vote at the Ulster Unionist Council, but winning it well enough to claim back enough of his Assembly dissidents to deny the anti-agreement forces the wrecking 60 per cent share of the total unionist bloc at Stormont.
Is it to be 1974 all over again? Not for the first time in this process, David Trimble must wonder if he will ultimately suffer the same fate as Brian Faulkner. And as he plots his path this weekend, the irony certainly will not be lost on him: that the man who moved the motion against Faulkner at that fateful meeting of the Ulster Unionist Council 25 years ago was one John David Taylor.