The import of what Mr Jeffrey Donaldson did in resigning the Westminster whip on Monday was a declaration of all-out conflict with Mr David Trimble.
"If you want me out, you will have to force me out," was his effective taunt to the Ulster Unionist leader.
He is still hesitating over directly challenging for the leadership or (same thing) throwing down a no-confidence motion against Mr Trimble at another Ulster Unionist Council.
But what happened on Monday, and what followed at UUP headquarters yesterday, seem to be leading inevitably to that terminal point.
Mr Trimble took up the challenge yesterday by persuading his party officer board to initiate disciplinary proceedings against Mr Donaldson and his fellow rebel MPs, the Rev Martin Smyth and Mr David Burnside.
Mr Trimble granted that it was not "unreasonable speculation" to state that this is what Mr Donaldson wanted him to do. Sources in the Donaldson camp also confirmed that this is part of the plan to dethrone Mr Trimble.
By taking him on Mr Trimble was not falling into the Donaldson trap, however; rather he was doing "what a man's gotta do". To ignore the gauntlet would have been a fatal sign of weakness. He had no other option.
The Donaldson battle plan seems fairly straightforward. If the disciplinary committee under the Enniskillen solicitor, Mr Raymond Ferguson, recommends the expulsion of the three MPs then they are almost certain to appeal that decision to the 110-member UUP executive.
In normal circumstances Mr Trimble has a majority of loyalists on the executive. There is some muttering among party waverers, and Mr Donaldson could swing some previous Trimbleites to his side. Odds at the executive, however, would seem in favour of Mr Trimble holding sway.
There has also been talk of a Gang of Six former Assembly members and other party members striving to find a compromise candidate to unite the party.
Trouble is, as one former MLA aligned with this embryo caucus said, there is no candidate at the moment acceptable to the two groupings. "That could happen later, but first the cloud has to lift on this Donaldson-Trimble business," he said.
The Donaldson bloc will continue to make life difficult for Mr Trimble, operating the process of death by a thousand cuts before seeking to move in with the coup de grâce. An example of that was Mr Donaldson's ally, Ms Arlene Foster, resigning from the 14-member officer board yesterday.
A well-placed source also hinted yesterday that the Orange Order would be shortly entering the fray on Mr Donaldson's behalf, further pressurising Mr Trimble. The purpose of all the manoeuvrings is to shake confidence, if not in Mr Trimble then in his supporters.
If the executive goes against the three MPs then under the party's rules any expulsion or suspension decision cannot be appealed to the 900-member UUC. It would not be difficult, however, for another UUC Donaldson-Trimble showdown to be requisitioned.
A question, which was unanswered yesterday, was whether in such circumstances Mr Donaldson, Mr Smyth and Mr Burnside would be entitled to attend the UUC.
There are issues here that could end up in the courts, again contributing to the sense of imminent implosion within the UUP.
"I suspect the council may have to have a say in this matter before it is over," said Mr Donaldson yesterday.
His hope appears to be that when a UUC meeting is eventually called Mr Trimble will be so weakened by then that enough of the 54 per cent who stuck with him last Monday night week will switch sides.
Mr Trimble, as was evident yesterday, is taking the battle to Mr Donaldson. He spoke of the necessity for speedy action and to that effect the disciplinary committee may meet as early as this morning.
How this concludes is still unpredictable. Mr Trimble has demonstrated again and again that he is no quitter, but this really is his toughest test.
Indeed he may have to leave in the short to mid-term, but if he does he wants to walk away from the field, with Mr Donaldson lying on it, dripping political blood.
If he has to go he wants to go at a time of his choosing, not Mr Donaldson's.
