The Taoiseach is ready to deploy large numbers of extra security personnel in Border areas as part of any agreement on further British demilitarisation in Northern Ireland.
This became clear last night as Dublin and London continued intensive efforts to avert a full-blown crisis in Northern Ireland's political process in the aftermath of President Clinton's three-day visit to Ireland and the United Kingdom.
Mr Ahern and the British Prime Minister, Mr Blair, are expected to meet to review progress in the ongoing negotiations within the next few days.
Irish sources last night confirmed the Taoiseach's determination to finally break the continuing deadlock on the inter-related issues of demilitarisation and IRA decommissioning, policing and Mr David Trimble's ban on Sinn Fein participation in meetings of the North-South Ministerial Council.
The joint purpose of both governments is to secure a lasting resolution of all outstanding issues of concern to unionists, nationalists and republicans, and so "fireproof" the Belfast Agreement against further attack and break the cycle of challenges to Mr David Trimble's authority at the Ulster Unionist Council.
At the same time it emerged that initial consideration has been given to "freezing" the political institutions established under the agreement if the parties fail to resolve matters well in advance of next year's expected British general election.
The London-Dublin negotiations have assumed added urgency with Sinn Fein's legal challenge to Mr Trimble's ban due to begin in the High Court in Belfast this morning and with a judgment anticipated early next month at the latest.
Well-placed sources in London and Dublin believe the British government is strongly disposed to make a major move on demilitarisation, which the Taoiseach believes should secure a package of measures resulting in the lifting of Mr Trimble's exclusion of Sinn Fein from North-South meetings and in putting IRA weapons "beyond use".
One option being widely canvassed in both capitals is for the IRA to agree to concrete over arms dumps which have already been opened to the international inspectors.
Sources yesterday confirmed that any "concrete" deal which would successfully take the process over the impasse and beyond the expected meeting of the UUC in January would have to involve SDLP endorsement of the new policing dispensation following the implementation of the Patten reforms.
However, Mr Blair is understood to be facing strong opposition from his security chiefs to any proposal to dismantle army watchtowers along the south Armagh hills. Security objections are twofold.
They say the observation posts provide essential cover for forces on the ground and that any reduction would be premature and dangerous - not least politically for Mr Blair - at a time when the British government has warned Londoners to be alert to the possibility of a pre-Christmas offensive by the "Real IRA".
The suggestion that large numbers of Irish security personnel be deployed along the Border springs from the Government's recognition that any "security gap" resulting from high-profile demilitarisation moves would have to be closed.