Mr David Trimble may put forward a high-risk, hardline proposal at today's meeting of the Ulster Unionist Council in order to resist the threat to his leadership from the sceptical wing of his party.
The First Minister was last night considering a move which would be distinctive but may be seen as just as uncompromising as the strategy being pursued by Mr Jeffrey Donaldson.
Anti-Belfast Agreement Ulster Unionists, and even some of his supporters, believe Mr Trimble could be fatally damaged at today's meeting of the 900-member Ulster Unionist Council, although last night the UUP leader appeared determined to resist the challenge from Mr Donaldson.
The reason the British and Irish governments are concerned is that in order to survive as leader Mr Trimble may feel compelled to move to the uncompromising territory occupied by Mr Donaldson.
This could involve some form of proposal which would threaten the future of the power-sharing Executive and Assembly.
"Don't write off David Trimble yet; he could still produce a rabbit from the hat," said a Trimble supporter last night.
Mr Trimble hinted on BBC and UTV last night that, in the absence of a last-minute Trimble/Donaldson compromise motion, his proposal would focus on a demand that the IRA fully disband.
"Some people in the republican movement believe that a ceasefire is enough. It is not," he said.
He said paramilitaries had failed to live up to the Mitchell Principles on operating by totally peaceful and democratic means. "Those means require that we see an end to paramilitarism in all its forms."
He also indicated that while he might move some distance into the Donaldson camp, he is anxious to ensure that he is seen to be dictating policy.
He was also critical of his internal opponents. "The only regret I have about the (council) meeting is that it distracts attention from the failure of republicans and makes it look as if there are unionists who want to destroy the progress that has already been made," said Mr Trimble.
Any demand for the IRA to disband would cause great concern to the British and Irish governments, who believe that the last way to achieve such an objective is by unionist diktats.
Mr Trimble and Mr Donaldson met at Hillsborough for almost two hours yesterday, but could not agree on a compromise motion to unite the Yes and No wings of the council today.
Mr Donaldson appeared determined to persist with a hardline motion which seeks the phased expulsion of Sinn Féin ministers Mr Martin McGuinness and Ms Bairbre de Brún from the Executive.
Previously, the Donaldson/Burnside wing of the party failed to win the support of the council because its proposals were viewed as unachievable. However this time Mr Donaldson believes he has fashioned a motion which will prompt enough waverers on the council to support him.
Meanwhile, the Taoiseach said yesterday he hoped the Ulster Unionist Party and unionist community would see the benefits of continuing to implement the Belfast Agreement, writes Mark Brennock, Political Correspondent.
Asked what would happen if Mr Trimble was replaced by an anti-agreement UUP leader, he said: "I'm not sure how the Executive could survive in those circumstances, and that would be very bad for the whole peace process. I prefer to think positively and hope it doesn't happen."
He emphasised that the agreement had brought benefits for the unionist community.