Whatever made Andrew Mitchell think he could hang on?
The moment he denied calling a Downing Street police officer a “pleb”, while being mysteriously unable to confirm exactly what he did say, his fate was sealed.
As usual in politics, the truth is only occasionally helpful. More important is perception, and as far as many voters are concerned, Andrew Mitchell insulted a policeman, and then tried to wriggle out of it.
He tried an apology. It didn’t work. And that’s when he should have quit.
But instead he tried to cling on, like so many doomed Cabinet ministers – both Labour and Conservative. And like most of them, it was never going to work.
Yet in the end it wasn’t public anger, or police fury, that finished off the now former Chief Whip. It was the reaction of his fellow Tory MPs.
Away from the Commons, Mr Mitchell felt he could tough it out. Returning to Westminster, he found few friends among the backbenchers he was paid to keep in line.
They were left wondering how to explain that the party of law and order was represented by a man who thought the police were “plebs” who should “learn their place”.
If only Mr Mitchell had come to the same conclusion a couple of weeks earlier. He wouldn’t have had the humiliation of announcing he’d stay away from the Tory conference, and he wouldn’t have forced David Cameron into another public show of support.
The Prime Minister rejected Ed Miliband’s claim, that his Chief Whip was “toast”. Forty-eight hours later that’s exactly what he was.
But David Cameron has mishandled the affair just as much as Andrew Mitchell. He should have realised he was doomed, and walked away. But Mr Cameron should have realised it too, and should have acted on it.
And it’s given the Prime Minister a real problem. Labour has struggled to find a consistent, successful way to attack the Tories.
But Plebgate has brought back that old idea of the Tory toff, out of touch, looking down his nose at ordinary people.
It doesn’t help when the Chancellor’s caught in a train’s 1st class carriage with a standard ticket, nor when a Defence Minister’s accused of trying to have protesting veterans thrown out of Parliament.
While ministers repeatedly chant “we’re all in this together”, they send a very different message.
In a way, they’re victims of their own ham-fisted attempts to look normal. If George Osborne had got into a limo rather than onto a train he’d never have had that embarrassing meeting with a ticket inspector.
And if Andrew Mitchell had done the same instead of trying to cycle through the Downing Street gates, he’d still be Chief Whip.
Meanwhile, I’m sure the timing of his resignation, an hour or so after the Chancellor’s embarrassing arrival at Euston, was a complete coincidence.