The furore over Tony Blair's leadership has been re-ignited by Charles Clarke's criticism of Chancellor Gordon Brown's behaviour. BBC correspondent Robert Peston, who has written a biography about Mr Brown, reflects on the chancellor's role in the events of the past week.
Tony Blair and Gordon Brown have a distorted and hostile view of each other that verges on paranoia. And they also seem to regard each other as possessing almost superhuman powers to foment trouble.
Gordon Brown will be angry that he is being accused of sowing disunity
They will, for example, always deny in public that they take any notice of what commentators in the media say about them.
But in practice they are convinced that certain journalists are fully paid-up Blairites or Brownites, working surreptitiously to further their respective heroes' cause with a zeal redolent of the battle between Bolsheviks and Mensheviks.
And they also believe that many MPs and ministers are simply puppets, whose utterances are controlled either from 10 Downing Street or from the Treasury. The truth, however, is rarely that simple.
The notion that Brown could simply rein in opposition to the prime minister with a "click of his fingers", as suggested by the former home secretary, Charles Clarke, is not quite credible.
None of which is to say that Brown has never - or would never - encourage his supporters to destabilise the prime minister.
But much more characteristic of him is that he turns the Nelsonian eye on guerrilla action against 10 Downing Street by Brownites.
Brown will be seething at the accusation that he alone is sowing disunity and blackmailing the prime minister.
From his point of view, Blair started it (way back in 1994, when Blair nicked the leadership from under his nose, as he saw it, but there really isn't time to go into that now).
If he hasn't been shouting that he wants the prime minister to go on and on - as some would like him to do - that is because there is a limit to how far even he is prepared to stretch the meaning of words in the cause of elusive harmony.
What he has said with tedious regularity over years is that he puts the interests of his party first.
And he does not believe that it is in the interests of his party for the prime minister to delay his departure.
Why not? Because the longest leadership campaign in British political history has now started.
It is unlikely party harmony will prevail at the Labour conference
Rather than governing, cabinet ministers will stake out their claims to succeed Blair (or Prescott, since he is expected to resign as deputy leader when Blair goes). Factionalism could become endemic.
That's why Brown has largely kept his own counsel in the past few days - even while he and Blair risked alienating voters by appearing to squabble privately over the leadership as though it were some chattel in a divorce case.
It's also why, when he broke his silence on Thursday, he simply made a general statement to the effect that he would support the prime minister in whatever decision he makes about the timing of his departure - and that such a decision must be taken in the interests of the party and country, rather than private individuals.
However, what should be putting the fear of impending apocalypse into Blair and Brown is that loyalty - and disloyalty - are habits of mind. The thrill of rebelling for MPs can become addictive.
That an outbreak of civil war should have occurred so close to their party conference - when the temptation for Brownites and Blairites to engage in bloody combat is always at its strongest - is particularly dangerous for them.
It is almost inconceivable that peace and harmony will rein at the annual gathering of the party faithful towards the end of September, when alcohol is plentiful and sleep is a rare commodity.
So here's the great fear for Brown. Even if he is a shoo-in to replace Blair, he may well be inheriting leadership of a party that by then will be unmanageable and ungovernable.
Which would probably make it unelectable too.
Mr Brown is due to be interviewed on Sunday AM with Andrew Marr on BBC One on 10 September at 0900 BST.