Big two risk serious reputational damage if they fail this time
The chances are Stormont will trundle towards a deal over the next week or so - but will it last? And will it be comprehensive?
The two governments, the DUP and Sinn Fein now all probably have more to lose if it fails than if it succeeds.
The British and Irish governments can't afford to let Northern Ireland seem ungovernable.
If Sinn Fein lose devolution and give power back to London, it will look like their policy of political engagement was botched.
And the DUP know that, even with increased representation at Westminster, their influence will wane without Stormont. Thirty years ago the Anglo Irish Agreement showed what happens when talks fail; the two governments step in.
The 1985 deal guaranteed that Northern Ireland's status could not be changed without the consent of people here. Mrs Thatcher, who signed the Agreement with Garret Fitzgerald, thought that would satisfy unionists.
In return, the Irish government got a secretariat here and a right to make recommendations on behalf of nationalists. Mrs Thatcher's intention was to bring the Irish on board for a clampdown on the IRA, which would isolate them.
Mr Fitzgerald also wanted to isolate republicans, but his method was to strengthen the SDLP and address nationalist grievances.
Mrs Thatcher had a worse relationship with unionist leaders after the agreement. In her autobiography she introduces a story about a meeting with UUP leader Jim Molyneaux and the DUP's Ian Paisley by revealing: "I was also confirmed in my impression that one of the problems of Northern Irish politics was that it no longer attracted enough people of high calibre."
That is the sort of outcome you get from opposing something the two governments have adopted, and the big parties won't want it.
The problem for them will be sustaining it in the face of more Tory cuts. Chancellor George Osborne has already got four departments (transport, local government and environment departments, plus the Treasury) to agree to 30% cuts and intends taking £30bn out of welfare.
Will our local parties be able to handle that without another breakdown in a year or two?
The big two can't count on the UUP or the SDLP. The latter have their conference and leadership election on Saturday and it will be tempting to wait until that is over to decide.
This time, the big two will have to hold their nerve in the face of opposition if any deal is to survive.