Now comes the big question for nationalists: can the deal be sold to the grassroots? There are two answers at this stage: probably and maybe, the first applying to the SDLP, the latter to Sinn Fein. This is where Hume-Adams may have to re-enter centre-stage.
A member of the Irish Government talks team posed the question a different way, directing it to unionists and nationalists: "Is this agreement going to be an anchor or a depth charge?"
Certainly in the overall context of nationalism, republicans more than SDLP politicians will experience turbulence before finding calm waters.
As Mr Hume and Mr Adams separately drove out of Castle Buildings, Stormont, yesterday evening they might have been musing on how the long, weary, dangerous route to this important moment in Irish history was charted. It began in 1988, a year in which Mr Hume consistently challenged republicans to accept that IRA violence was self-defeating and counterproductive.
Mr Adams in turn challenged Mr Hume to provide the movement with an alternative to violence.
There was no meeting of minds, the IRA killing machine continued, but vitally it was the genesis of the Hume-Adams relationship. That relationship had to find its way past many minefields in the subsequent 10 years, but it was crucial in promoting the IRA ceasefires and in aiding Sinn Fein's coming out of the political cold. That relationship may also be crucial in keeping, to use a unionist phrase, "the greater number" of republicans on board.
Mr Adams is 49. Mr Hume is 61. Mr Hume has dedicated his political life to resolving this problem. Equally Mr Adams, in the latter part of his career, has invested great energy in winning a deal he can sell to the bulk of the republican movement. Having come this far, is it all going to be scuppered?
One of the problems in finding an answer is that the broad unionist and nationalist parties have embarked on this process from different ports. For unionists, it is a case of getting a deal that will secure the Union, bring relative peace and sideline Sinn Fein: for nationalists, it is a case of achieving an Irish dimension to a settlement, bringing relative peace and keeping Sinn Fein on board in order to keep the IRA on board.
So, must it always be a case of what's good for unionists must be bad for Sinn Fein, and vice versa? Can this deal simultaneously satisfy and annoy the main antagonists? There were great difficulties with the initial Mitchell synthesis paper for the UUP. Now, with the overhaul of that document in an attempt to comfort unionists, can Sinn Fein tolerate it?
The SDLP can wear this compromise settlement, although as with every other party it will have misgivings. Mr Hume, the party leader, will be anxious to calm any troubled waters on which Sinn Fein must sail. He will be to the forefront in trying to thwart any unionist attempts to prevent them getting close to the centre of power of this proposed new political dispensation. Mr Adams and his colleagues will need all the help they can get.
As the deal was being done, Republican Sinn Fein, in a mirror image of the DUP's reaction, was completing its media faxes denouncing the deal as a sell-out. The 32 County Sovereignty Committee will push the same line, that Sinn Fein is not a "true republican" party. The Continuity IRA group, with elements sympathetic to the views of the Sovereignty Committee, and the INLA may be planning further paramilitary actions to try to sink this deal. As is obvious, they all have the power, and perhaps the inclination, to damage, bomb, kill and destroy. In the cold light of print on paper, other republicans, loyal to the Provisional movement, may be getting queasy about what they are being asked to subscribe to. They have the choice of signing up reluctantly, signing off from the movement, or signing up with the dissident paramilitarists.
Sinn Fein, conscious of this, has been "weeding out" dissident members from the organisation, in advance of the party's crucial ardfheis next Saturday. What is significant is that these expulsions were executed without notable discord within the broad Provisional movement.
Nonetheless, some degree of metaphorical bloodletting must take place at the ardfheis. Certainly Mr Adams and Mr McGuinness will be able to argue with conviction that no other republican would have got a better deal from the talks.
There is much emphasis on whether Sinn Fein will accept or acquiesce in this settlement. Mr Trimble's hope, it seems, was that it would acquiesce; acquiesce being, in this case, a synonym for tolerating any settlement. Acceptance, however, could mean Sinn Fein seeking executive positions on the proposed new Assembly, which would undermine unionist desires to isolate Sinn Fein. This would require constitutional change within Sinn Fein itself, but it is a possibility; a case of Sinn Fein calling the unionist bluff.
On Monday night it seemed Sinn Fein might embrace the deal, which must have caused great alarm among unionists who could not wear the idea of Mr Adams or Mr McGuinness serving on an Assembly executive or cabinet-type body. Mr Trimble's raising of the decommissioning issue yesterday was a reflection of that concern to keep Sinn Fein out, or sidelined. After the redrafting of the Mitchell document, Sinn Fein will take stock before deciding on its final position.
It's a pretty good bet despite all the anxiety among republicans that, if Mr Adams and Mr McGuinness want to sell the deal, they will sell it. A senior republican source commented recently: "If Adams can get 70 per cent of the movement behind a deal he will go for it."
The mood music yesterday evening was that Mr Adams and Mr McGuinness will partially sell it, i.e. sign up to the document in a "semi-detached way". "We will give it a fair wind," Mr McGuinness said.
Mr Adams and Mr McGuinness have worked hard to teach the republican constituency that there is not going to be a united Ireland in the short term. For several months they have been citing the Framework Document as the bottom line, which with its reference to North-South bodies with executive powers is a long way from the ultimate republican goal.
Equally, in various meetings and carefully choreographed media statements or interviews, they have been preparing the faithful for a compromise deal. They have, in fact, been doing what Seamus Mallon for years urged them to do: tell republicans what was possible, and what was not possible.
The focus has been on "transitional" arrangements and the "equality agenda", policing and prisoners. These issues are substantially addressed in the document. Mr McGuinness has said that republicans "can say with considerable legitimacy that British rule in the North of Ireland is losing its grip". That argument will become a mantra in the days ahead.
The Continuity IRA, and similar groups, will accuse Mr Adams and Mr McGuinness of selling the republican birthright. But the Sinn Fein leaders know that, particularly in the North, most republicans want the war to end, providing they can argue that an agreement is a staging post to a united Ireland. Inevitably there must be some form of split, but at the moment it is a split the republican movement believes it can handle.
Mr McGuinness recently expressed his absolute confidence that the Provisional movement was solidly behind the leadership, despite the verbal broadsides from republican opponents. Most trust Mr Adams and Mr McGuinness, and it will be for them to decide whether or not Sinn Fein will anchor itself in this deal or blow it out of the water.