As reported in Monday's Irish Times, British ministers were already voicing private fears that a bad result for Mr David Trimble's Ulster Unionists could force a second suspension of the institutions established under the Good Friday accord. Their assumption, of course, was that the power-sharing Executive would at least survive the campaign itself.
That assumption may be about to be seriously tested by the bombshell announcement Mr Trimble dropped on the British Prime Minister, Mr Tony Blair, yesterday, shortly before he journeyed to Buckingham Palace for his audience with Queen Elizabeth, seeking the dissolution of the 1997 parliament.
Now Sinn Fein ministers are being told their continued presence in government - indeed the survival of the Executive itself - is contingent on the IRA undertaking substantial decommissioning of weapons by the end of next month. As they prepare to face their own electorate, it remains unclear precisely how the Sinn Fein leadership will respond.
While the British and Irish governments nervously monitored Sinn Fein's initial response, however, there was no disguising the relief and delight in Ulster Unionist circles last night. Extensive consultations apparently preceded yesterday's shock announcement of a second post-dated letter of resignation. And Trimble loyalists forecast that the tactic - which forced the first suspension of the Executive in February last year - would now enable pro-and anti-Agreement candidates to coalesce around a common UUP manifesto, and put Dr Paisley's DUP firmly "on the back foot".
The immediate and obvious charge courted by Mr Trimble is that he has put party before the agreement and country. That will be attended, moreover, by the suspicion that he has acted out of desperation in face of the DUP's victory in last September's South Antrim by-election, and its vigorous challenge now in three previously rock-solid UUP seats - Strangford, North Belfast and East Londonderry. In fact, Mr Trimble, for some time now, has given a pretty convincing impression of one wholly unconvinced by predictions of electoral gloom and doom. He is aware that, even among close supporters, there have been whispered conversations about what might happen should the election results oblige him to fall on his sword. A Jeffrey Donaldson-Reg Empey "dream ticket" has been touted in some quarters as a possible means of unifying the UUP should anti-agreement forces gain an undisputed upper hand.
The UUP leader is said to be sanguine about such backstage intrigues. Apparently buoyed by private opinion poll evidence, he told the BBC's Newsnight programme last Thursday that his party was going to fare surprisingly well.
By most immediate assessments, Mr Trimble has strengthened the prospects of his party's most endangered candidates. Which his allies say contains the whole point: the UUP leader and First Minister has acted to force a showdown over decommissioning. After the trauma of the first suspension, Mr Trimble was fond of saying he had shown he had "a bottom line" and that it hadn't gone away. London and Dublin were last night left grasping the clearest indication that he meant it.