There were some clues that he was lying, Clare

The reaction of many people to Clare Short's resignation must be the same as when a woman leaves a dreadful bloke. She's crying "He never listens to me" and everyone else is thinking: "We told you that all along, you idiot." Then, when she blubbers "He promised he'd involve me in rebuilding Iraq", you almost feel like patting her on the head and saying "We told you he didn't mean it you silly girl".

Now she's managed to have supported a war that was opposed by most of the world but resigned over who gets to rebuild the place after the bombing she backed. It would be like someone leaving the mafia, saying: "It's not fair, you said I could decide who cleared up the rest of the horse."

For the eagle-eyed, there were one or two clues that the promise of UN involvement in post-war Iraq was a fib. Inspector Morse might have said: "Hang on, Lewis, if they want the UN to run the place why the hell have they stopped them having any say in whether there's a war in the first place? And this dossier about Saddam's weapons is a student thesis. And this claim about links with Bin Laden is entirely made up. You know what, Lewis, I'm beginning to wonder whether this all adds up to Blair not entirely telling the truth."

Which is why her resignation appears to have been made over an issue of principle, the principle being that she was about to be sacked, which she found morally unacceptable. It also seems a little odd, given that she was about to be sacked and that her replacement was lined up to take over 10 minutes after she left, that she claims Blair "begged me to stay". She's turning into David Brent from The Office. Her original press statement probably read: "He's gutted, Blair, gutted. But in life – you have to go on, and I'm basically a shark, and sharks have to keep moving. He's in tears, Prescott, but I've told him – new horizons, John, horizons."

She also says she suspected trouble shortly after Labour were first elected, at a cabinet meeting in which everybody opposed the Dome. Then Blair went straight to the press to announce they were going ahead with it. So at that point she must have made the decision that the only way to exert influence on the government was to hang on in there and be ignored.

In response to Robin Cook, who's said she should have resigned along with him before the war, some supporters of Short have said the impact has been greater this way, with two separate and staggered resignations. Which is like saying the huge march against the war would have had more effect if, instead of all one and a half million going on the same day, we'd have gone three at a time for 500,000 days.

Despite being a discredited figure, one of her main points is hard to dispute, which is that the reasons Blair originally gave to justify the war have now been abandoned. In particular, the search for weapons of mass destruction, which was the whole reason for the thing, has been virtually called off, with the inspectors sent home. All year they screamed about these bloody weapons, how the war had to be fought because Saddam was hiding them and threatening the planet and Hans Blix would never find them; and now they go: "Oh, they don't really matter do they?" It would be like if the wily coyote finally caught the roadrunner and said: "To tell you the truth, I'm not that hungry".

Many supporters of the war who yelled daily about the weapons of mass destruction are now saying that the lack of these weapons is of no importance. There's probably someone in the Senate saying: "Weapons were never the issue. The point is, we've destroyed those ghastly paintings in his palace, and for that the world should be grateful."

Blair is now acting as if the millions who opposed this war have forgotten all this. But their resentment filters through in a variety of ways so that, instead of wallowing in the glory of a victorious war, his election results get worse and his party more divided. In some ways he's in a similar position to Thatcher in the months after the poll tax riot, when she appeared to be safe but had reached a degree of unpopularity that made her vulnerable to an assault from her enemies on her own side.

In the meantime, Blair prides himself on his groundbreaking act of replacing Clare Short with the first black woman in the cabinet, a gesture slightly tempered by t he fact she's a black unelected baroness. From the way some Blair supporters have claimed this as groundbreaking and radical, you'd think he'd appointed a 16-year-old black girl from the top of a bus, whose maiden speech would be: "If the party opposite disses the euro once more, I swear I'll give them such a wicked beating. But not Kenneth Clarke 'cos he is fit."

But by now Clare Short has probably already rung Blair a couple of times to say: "All right Tony, I'll come back – just this once, but this is the last time. Please."