The Ulster Unionist Party's 110-member executive meets in Belfast this evening ahead of Monday week's Ulster Unionist Council (UUC) showdown between Mr David Trimble and Mr Jeffrey Donaldson.
The Ulster Unionist leader is this evening due to put down a motion for the UUC meeting demanding that the home element of the Royal Irish Regiment, numbering 3,000 troops, is retained in the event of full demilitarisation.
Mr Donaldson, MP for Lagan Valley, may also elaborate at the executive today why UUC members should support his motion calling for a total rejection of the Hillsborough Joint Declaration.
Mr Donaldson has signalled that he may leave the Ulster Unionist Party if his motion is rejected. This is interpreted as an effective challenge to Mr Trimble's leadership and the UUP leader must decide how to resist that threat.
Trimble supporters however said that he would not be revealing today what strategy he would employ to try to finesse Mr Donaldson on Monday week.
One source said tactically it was too early for Mr Trimble to declare how he would approach the UUC meeting. "This executive meeting is just a warm-up," he said.
The executive meeting nonetheless could be a tense affair with Trimble and Donaldson supporters rehearsing some of the arguments which will be employed by both sides at the UUC.
