A four-week battle for the future of Mr David Trimble, the UUP leader, and the Belfast Agreement begins in earnest today when pro and anti-agreement unionists gather in the Waterfront Hall, Belfast, for the annual conference of the Ulster Unionist Party.
Mr Trimble was last night putting the final touches to his conference speech, which must serve as a rallying cry for his supporters, while Mr Jeffrey Donaldson and the No wing of Ulster Unionism maintained their assault on the First Minister and the agreement.
The scene has been set for a bitter internal unionist squabble in the weeks ahead. Mr Trimble and Mr Donaldson used local newspapers and the Northern Ireland airwaves to put their conflicting cases yesterday.
Over 400 people are expected at today's annual UUP conference. The organisers have been taking measures to try to prevent any unruly scenes from No unionists during Mr Trimble's keynote address this morning, prompting claims that the conference is being packed with Yes unionists.
Both sides have acknowledged that the real test for Mr Trimble will be at the Ulster Unionist Council meeting expected to take place either at the end of this month or, more likely, on November 4th. Then Mr Donaldson will try to tie Mr Trimble to a policy of withdrawing from the executive if the IRA does not disarm, potentially forcing Mr Trimble's resignation.
Mr Trimble, in a series of interviews yesterday, indicated that while he would today highlight issues such as policing and IRA decommissioning, he was still prepared to stand by the Belfast Agreement. His supporters are hoping that he can deliver an invigorating speech today to boost confidence and strengthen his position for the challenges ahead.
The Taoiseach, Mr Ahern, and the British Prime Minister, Mr Blair, who are due to meet next Tuesday to discuss the political situation, are also hoping Mr Trimble can convince wavering unionists that the agreement is the only way forward.
Mr Trimble's message that there was no alternative to the agreement was encapsulated in a full-page article by him in yesterday's Belfast Telegraph where he singled out Mr Donaldson and warned there was no future in pursuing the agenda of anti-agreement unionists.
"We know that a marginalised unionism is a losing unionism. That is the lesson of the sterile decades before the imposition of the Anglo-Irish Agreement of 1985 and the wilderness years that followed. But I have a message for unionists: the bulk of the pain is behind us, not in front of us," he wrote.
"If we throw away the agreement - as Jeffrey Donaldson seems to want - we lose all its ongoing positive benefits; not only the Assembly but a greater credibility for unionism within the United Kingdom than at any time in a generation," added Mr Trimble.
Mr Donaldson accused Mr Trimble and other Yes Ulster Unionists of attacking him personally. "I very much regret the decision that has obviously been taken by David Trimble and his team to target me specifically. It's clear now that they want to personalise this debate. They've lost the argument and they want to concern themselves with personalities. I think that's very sad," he said.
Mr Donaldson said the planned Ulster Unionist Council meeting was not a direct challenge to Mr Trimble's leadership. However, he did not rule himself out from a future challenge and said that if the vote at the council went against Mr Trimble it would be up to the UUP leader to decide whether or not to resign.
The South Belfast MP, the Rev Martin Smyth, who failed in his bid to oust Mr Trimble as leader in March, re-entered the frame yesterday. He too refused to rule himself out from another tilt at the leadership.
Nationalist and republican politicians last night urged Ulster Unionists to maintain support for the agreement. The Sinn Fein Minister of Health, Ms Bairbre de Brun, said: "It is now vital that those unionists who genuinely want to see the agreement implemented begin to speak up and have their voices heard. The unionist pro-agreement message has gone by default for too long."
The SDLP Assembly member Mr P.J. Bradley said there was no alternative to the agreement other than a likely return to violence and instability.
Follow the latest developments at today's Ulster Unionist Party conference on The Irish Times website in Breaking News at www.ireland.com