It was not for nothing that the Tory high command sent Oliver Letwin to a retreat during the last general election. Some naive commentators may say that the shadow chancellor has started a "mature" debate over tax and spend but the problem is the voters won't have a clue what he's on about.
Talk about percentages of GDP does not make for election-winning slogans. They will now know he wants to make savage cuts in public spending. They will know how much, because Labour will tell them.
Letwin's problems aren't just that his sums don't add up. He is the problem. What on earth was he doing debating with a Labour MP on the Today programme? Can you imagine Gordon Brown, even in opposition, going on the radio to talk about his tax plans and discussing them with a Tory? On Newsnight, Letwin also had to face the Lib Dems. Hasn't he got the clout to demand a one-to-one interview?
One of the problems with Letwin is that he's too honest for his own good. He told the media that the right would say he was being too weak and the left would accuse him of "slash and burn". The Telegraph did say he was not cutting enough, but the phrase that he himself used, "slash and burn", will come back to haunt him.
Tony Blair was desperate for the political agenda to move on, and he's certainly got his wish. The dividing lines will now be drawn, even if they hardly exist, and Brown will inevitably savage Letwin every time he opens his mouth. The Chancellor spent years devising his economic policy. Letwin did it in just 100 days and it shows. A pint of Guinness in the Press Gallery bar for anyone who can name all the shadow chancellors Gordon Brown has seen off!