With his Dail majority down to one, after two by-election defeats last month, Ahern knows a peace deal may be vital to his government's survival. But for that to happen, he must convince his own party critics and a volatile republican rank and file that the final package can keep a united Ireland on the horizon.
Fears that it will simply enshrine partition accelerated IRA defections to violent splinter groups. Evidence of their growing organisation was shown by the huge car bomb discovered at Dun Laoghaire on Thursday.
Mr Ahern's suggestion last week of five-yearly referenda on Northern Ireland's constitutional status was floated to help slow IRA defections. Amid Unionist ire, he later softened this, saying he only saw such polls happening "in time". There would be no point in a poll "unless there was a prospect of change".
This was also pitched to doubters in and around his own Fianna Fail (FF) party, which complain trading Articles 2 and 3 of the Republic's Constitution compromises their "core values".
If Sinn Fein find a Blair-Ahern compromise too soft to placate their foot-soldiers the party may opt for an uneasy half-in half-out stance, allowing them to play a full part in a referendum campaign while withholding endorsement of the entire package.
The only leeway Dublin might have to offer to unlock the impasse is, Dail Opposition sources suggest, in varying the form that a "legislative base" for North-South bodies takes. This could be through an international agreement, rather than a direct parliamentary basis.Reuse content