The Ulster Unionist Party in Fermanagh/South Tyrone has chosen a pro-Agreement candidate to fight the upcoming general election.
Trimble loyalist James Cooper narrowly beat off the challenge of Arlene Foster, a close ally of dissident MP Jeffrey Donaldson, by a mere nine votes.
Had Ms Foster won last night, it would have precipitated an immediate crisis for Mr Trimble. His opponents within the party would have pressed for him to pull out of the power-sharing executive and demanded a new Ulster Unionist Council meeting.
Mr Cooper said the message of last night's vote is that unionists have given all they can and it is time to force republicans to deliver on decommissioning.
Ms Foster said that while she would support Mr Cooper, the vote showed the depth of disquiet amongst the grass roots at the lack of progress on arms.