This is exciting for the politics buff because no-one can predict the next move, the one after that, or the likely outcome for the Government.
Neither player is bound to take it further. Pundits claim they have to bring it to a head, but it's in their interests to say that. In reality Howard and Costello have lived with the tension this long and there is still plenty of room for them to say 'we strongly disagree as to the exact nature of that discussion, but won't be taking it further for now'.
Either could bring on a fight. But Bishop was wrong when on Lateline she put the ball entirely in Costello's court.
If Costello is telling the truth, and I think most people believe he is, then he has every right to stand back and say 'No, I'm just going to continue to assert the truth, let John decide whether he wants to do anything about it'.
The idea that he doesn't have a point because any such deal would still have been subject to party room approval is wrong. It misunderstands the nature of the alleged promise. It would be obvious to those present that such a handover would not be a fait accompli. What Howard was allegedly promising was that he would stand aside and give his support in the party room to Costello.
That is not an unreasonable promise, it makes sense in the world of politics.
And the number of years that have passed does not diminish the wrong. It makes it worse. Costello has waited in the wings and given largely loyal support ever since. He has been shafted.
The timing of Costello's attack is difficult to fathom, however, and suggests a man at the end of his tether. He could have played down MacLachlan's note while endorsing it, let the issue slide a little for now.
I think there was a real chance that Howard was considering retiring before Christmas. Given uncertain polls over IR, an issue owned by Costello, the temptation to walk out on top and leave the mess to his deputy must have been stronger now than at any point in the past 10 years. I actually felt in my gut that it might happen, I haven't felt this before.
Now, if he goes voluntarily, it will look like he's bowed to the pressure or tacitly conceded to Costello's version of events. He won't be keen on that.
And the Liberal Party, if it comes down to a challenge? Anything is possible but they've shown many times over that they value winning more than integrity. Costello has ridden the wave for 10 years, he should know the score.
After all, the issue of whether Howard broke a promise is not the same as the question of who is more likely to win the next election for the Liberals.
Meanwhile, excitement ripples across the poliblogs: Fits celebrates good times, Mark Bahnisch says maybe nothing's going to happen at all, and Tim Dunlop says Howard:
hubristically and arrogantly, according to his own assessment, tried to organise the leadership for himself on the basis of a deal rather than a straight-out voteand asks
does anyone seriously think that he would’ve done this without offering something in return?
We wait. We drink coffee. We wait some more.