Hardliners, alarmed about Unionist participation in talks with Sinn Fein, are discussing plans to stand against Mr Trimble at a party meeting in less than two weeks.
Last year, because of the impending general election, the party waived the normal rule which requires the party leader to be re-elected at the annual Ulster Unionist Council.
Because of that, Mr Trimble will need endorsement at this year's meeting on 21 March. Any developments in the peace process may provoke a challenge from one of the party's disgruntled MPs, or a stalking horse.Adding to the pressure, a right-wing slate may be put up to contest eight senior party positions. A senior source said: "I would be confident that David Trimble will be re-elected; I would not be confident he'll get a clear run."
Another source said: "The general view is that the British, Irish and US governments think Trimble is going to do a deal." Several MPs have reservations about the direction the process is taking, including Willie Ross, Willie Thompson, Rev Martin Smyth and Cecil Walker.
The prospect of a challenge to Mr Trimble could paralyse the process for the next two weeks. Sinn Fein's top negotiators say they will not rejoin talks until they have seen Tony Blair. That meeting is due for Thursday, just before many talks participants leave for St Patrick's Day celebrations in the US.
The next round of serious talks is unlikely to take place until the week of 23 March - after the Ulster Unionist Council. Mr Trimble, aware of the head of steam behind the hardliners, is planning a protest when Sinn Fein returns to the talks, possibly involving a demand that the delegations sit in separate rooms.
Editorial, Section 2, page 4