The weeks and months of negotiations between the Ulster Unionists and Sinn Fein, and the efforts senior government officials devoted to them, are testimony to the sense that the forthcoming assembly elections could prove crucial in determining which leaders speak for Northern Ireland's unionist community.
The political architecture constructed by the Good Friday Agreement requires any power-sharing executive to be supported by a majority of both the nationalist and unionist communities.
That's why London and Dublin are so concerned about the possibility that Ian Paisley could topple David Trimble.
When the dust settled after the 1998 assembly election campaign, Mr Trimble emerged with a clear, if narrow, lead within unionism. The UUP took 28 seats, well ahead of Ian Paisley's DUP, which held 20 seats.
The DUP suffered from a splintering of the anti-Agreement unionist vote. Bob McCartney's UK Unionists notched up five assembly members, and three independent unionists were also returned - all of them sceptical about the Good Friday Agreement.
However, David Trimble's position was bolstered by the presence of two members of the Progressive Unionist Party.
Although linked to the paramilitary UVF, the Progressive Unionists were staunch in their support of both the Agreement and Mr Trimble's participation in the powersharing executive.
This complex picture gave pro-Agreement unionism a 30 to 28 lead over anti-Agreement forces.
However, Mr Trimble's lead was eventually eroded by the defection to the anti-Agreement cause of two of his assembly members, Pauline Armitage and Peter Weir.
DUP has benefited from internal UUP divisions
Their refusal to support Mr Trimble led to the bizarre manouvreing when members of the 'middle-of-the-road' Alliance and Women's Coalition redesignated themselves as temporary unionists in order to sustain the Stormont Executive.
The gains made by the DUP in the 2001 Westminster election, coupled with a sense that many unionist voters are increasingly disillusioned with the Agreement, have created an expectation that the DUP could be on the verge of becoming the biggest unionist party.
The DUP has benefited from the continuing bitter internal divisions within the Ulster Unionists and a belief that the smaller anti-Agreement unionist groups could wither away.
The DUP newcomers to Westminster are generally younger than the Ulster Unionists they replaced and have been stealing Sinn Fein's clothes in operating efficient constituency offices lobbying on bread and butter issues.
DUP strategists were rubbing their hands when they watched the planned Hillsborough deal implode.
The British and Irish Governments had hoped the deal would provide the Ulster Unionists with a platform to fight an energetic pro-Agreement campaign.
Instead, the failure of the deal has left the Ulster Unionists with no alternative but to move on to more sceptical terrain.
For the DUP, this is like playing a football match on your home ground.
Before announcing that David Trimble's days are numbered, however, any commentator would be wise to take stock.
Mr Trimble is nothing if not a survivor, and reports of his political demise have proved greatly exaggerated in the past.
Some Ulster Unionists argue that their leader's resolution in putting the Hillsborough deal on hold will have won him approval from his party's grassroots.
'Control the balance'
Once again, they say, he will be perceived as the man who stood up to the IRA. The perception that the Ulster Unionists' majority may be in doubt could also persuade those "lapsed" moderate unionists who have been reluctant to vote to go to the polls.
They might cast their ballots as much to stop Paisley as to back Trimble.
Moreover, the assembly elections will be fought on the PR "single transferable vote" basis, rather than first past the post.
This system has always tended to help bolster the political centreground, as voters don't tend to give later preferences to parties on either extreme.
Mr Trimble "is nothing if not a survivor"
All this means that the battle within unionism appears too close to call.
If the two main unionist parties emerged from the elections neck-and-neck, the future of any assembly could depend on the internal divisions within Ulster Unionism.
Three anti-Agreement members within the UUP, for example, could control the balance within unionism just as Peter Weir and Pauline Armitage did before them.
Given that a power-sharing executive is not likely to be reformed, this might all seem academic.
However, fresh negotiations are certain and the outcome of the election will govern the say each of the parties have at any review of the Good Friday Agreement.
So even if Stormont is not revived, for unionist politicians every vote will count.