Analysis: There was cautious optimism about the peace process from British and Irish officials at a sunny Hillsborough yesterday, writes Gerry Moriarty, Northern Editor
From crisp, bright afternoon into freezing dark night the Taoiseach, Mr Ahern, and British Prime Minister, Mr Blair, held court together in one of the splendid drawing rooms of Hillsborough Castle.
Mr Blair faces a possible war on Iraq but, according to his official spokesman, his commitment to breaking the political deadlock in Northern Ireland "speaks for itself".
Outwardly nobody was getting too excited about the Hillsborough encounters. Mr Blair's spokesman was probably on the button when he described the talks as "significant but not decisive". And neither was anybody contradicting him when he added that "nobody was revealing their bottom lines".
This might create the impression that everything remains amorphous and ill-defined. But politics appears to have moved beyond that position. As one senior Irish official put it: "I think the parties have a fair idea now where we are heading." And in broad outline Mr Ahern and Mr Blair are working to the following deal:
• The IRA verifiably demonstrating it has ceased all paramilitary activity.
• A twin-track timetabled programme of IRA decommissioning and British army demilitarisation.
• Sinn Féin endorsing the Police Service of Northern Ireland in return for the devolution of responsibility for policing and criminal justice to the Executive and Assembly.
• Ulster Unionists committing themselves not to collapse the Executive again.
Dublin, London and Washington, after numerous meetings with Mr Gerry Adams and Mr Martin McGuinness, are convinced the republican movement is serious about moving substantially and radically. That's because that is what Sinn Féin is telling the Irish, British and US administrations.
The lingering suspicion, however, is that republican interpretation of what is "historic, bold and imaginative", to use the buzz words of Mr Adams and Mr McGuinness, may not tally with Mr Blair and Mr Ahern's understanding of these words, and may be a far cry from what Mr David Trimble requires to enter into a May election campaign fully behind this potential deal.
Nonetheless, when you speak to British and Irish officials and observe the commitment of Messrs Ahern and Blair, it is clear the British and Irish view is that republicans are serious this time.
The notion of parallel IRA disarmament and British army toppling of its installations over a specific timeframe also makes sense. Sources say that the British generals can live with demilitarisation if there is a corresponding reduction in the IRA's capacity to wreak mayhem.
This also has potential to be sold in the republican heartland. For example, going way back to the start of this process in the early to mid-1990s, Mr Adams often said there could be no "unilateral" IRA decommissioning. A bilateral IRA-British army scaling-down of its arsenals and watchtowers would ensure there could be no claims of victory or surrender by either side. An honourable stalemate after decades of conflict.
Any deal would be virtually unworkable if Sinn Féin did not join the Policing Board. How could there be anything approaching a normal society if Sinn Féin was back in government while refusing to support the force dedicated to protecting that government?
There is still a lot of hard-bargaining to be done here. A commitment, which essentially is already in place, to create a department of justice in Northern Ireland - probably run jointly by unionist and nationalist/republican ministers - could convince Sinn Féin to finally make that historic leap on to the Policing Board.
Sinn Féin and SDLP politicians regularly raise the concern that if republicans finally bite the bullet on difficult issues, which in the past would have resulted in IRA court-martials, that Mr Trimble will say "thank you very much", but still refuse to go back into the Executive with Sinn Féin.
Ulster Unionists such as Sir Reg Empey say if republicans are genuine, then his party "won't be found wanting". Mr Adams would need firmer assurances than that, however.
Here there is concern that while potentially Mr Blair and P. O'Neill can deliver, Mr Trimble, even if he wanted to respond positively, will be held hostage to the Donaldson/Burnside No wing of the UUP, not to mention repetitive Ulster Unionist Council meetings.
According to one British source, this is not insurmountable. "I don't buy that David Trimble can't deliver," he said. "If what the IRA say and do is front-loaded to be of major and obvious significance, then Trimble could sell it to middle unionism."
That's still a tricky issue. There will be many more difficulties around that and the other aforementioned matters. But while it could all fail, the odds remain in favour of a deal. Mr Ahern and Mr Blair plan to return in early March, and while they always travel hopefully, they only travel when agreement is realisable.