New details began to emerge yesterday of the blueprint for progress in the peace process presented to the Northern parties by the British and Irish governments this week.
As the parties study the unpublished document, disagreement between Sinn Féin and the DUP over linking IRA decommissioning to the formation of a shadow Executive and Assembly is one of the main obstacles to restoring devolution, according to informed sources.
Republicans in particular are concerned that in the initial stages of what the governments hope will be a sequenced deal Sinn Féin and the IRA will be seen to be taking too much of the "pain" while the DUP will be making the "gain", The Irish Times has learned.
A key difficulty here is that as well as being required to make firm commitments to decommission fully and end activity the IRA is expected to allow independent Catholic and Protestant Church witnesses oversee IRA disarmament and provide future visual evidence of it.
Republicans want a more "balanced" sequencing arrangement whereby the IRA would begin but not complete decommissioning and thereafter the DUP would agree to nominate ministers to a shadow Northern Executive, it is understood.
In turn, the IRA would be expected to make a commitment to complete decommissioning before full devolution is restored, possibly by the end of the year or in January, to allow for the formal restoration of the Executive and Assembly by February or March.
Republicans argue that it is necessary that the DUP should agree to the creation of a shadow Executive before disarmament is completed so that it is clear that the DUP and republicans are demonstrating their bona fides to each other, sources said.
The main question is whether the DUP can be persuaded to join a shadow Executive before decommissioning is concluded.
"The problem is centred around both parties building up mutual trust, and at the moment Sinn Féin is arguing that initially at least, in terms of movement, it is one-way traffic in the DUP's favour," explained one source.
Another significant difficulty is the DUP requirement for some future photographic evidence of decommissioning. The governments believe this is necessary to persuade the DUP leader, the Rev Ian Paisley, to sign off on a deal.
Dublin and London are examining a number of possibilities that would meet the DUP requirement but would not be seen as an attempt to humiliate republicans.
One possibility is that the photographic evidence would only be produced in private to a limited number of unionists, and only after it was clear that the DUP was fully committed to power-sharing.
Republicans have rejected this request, it is understood, although Dublin and London hope they will change their mind. The republican offer of allowing a Protestant and Catholic Church representative to join decommissioning chief, Gen John de Chaste-lain, in overseeing future acts of disarmament still holds, it is believed.
There are also problems over how and when responsibility for policing and criminal justice would be devolved to the Executive and Assembly.
While there is continuing talk of slippage in these discussions beyond next Friday's effective deadline for agreement, senior sources said the governments were determined not to allow this process become bogged down in interminable bickering over clarification.
In the coming days of intensive discussions Sinn Féin and the DUP will be seeking clarification from Dublin and London on these and other issues.
Sinn Féin leaders such as Mr Gerry Adams and Mr Martin McGuinness briefed TDs, Assembly members and senior party officers on the Irish-British paper in Dublin and Belfast yesterday while Dr Paisley consulted with his Assembly members at Stormont.
Mr Ahern refused to say if he was optimistic or pessimistic. "I would be hoping we at least get to conclusions. I would hope they would be positive."