why you need economists

You can see why Marc Ambinder is a good pundit with his post-mortem on the Obama - Clinton debate:

Keeping the score card, there's no way Obama could fared worse. Nearly 45 minutes of relentless political scrutiny from the ABC anchors and from Hillary Clinton, followed by an issues-and-answers session in which his anger carried over and sort of neutered him. But Hillary Clinton has a Reverse-Teflon problem: her negatives are up, and when she's perceived as the attacker, the attacks never seem to settle on Obama and always seem to boomerang back on her. So it would be unwise to declare that Hillary "won" the debate in the dynamic sense just yet. (How much money will Obama raise off this debate? $3 million? $4 million?)
A lot of stuff that Obama doesn't [want] Pennsylvanians to think about were the subject of fairly detailed questions. Obama's supporters are already blaming the "establishment" -- that is, the powerful institution of the mainstream media -- for the tone of the debate. This sets up a blowback scenario wherein his supporters will rally to his defense and lash out at the media very loudly. ...

A fine analysis. But look at his live blog wire:

0908 [PM EST]: Charlie asks Obama about the capital gains tax and its inverse relationship to revenue. "Why raise it at all?" Obama: "I would look at raising the capital gains tax for the purposes of fairness." So -- doesn't matter if it brings in more money to the Treasury, he's going to raise the tax for reasons of distributive justice?

Ambinder makes a perfectly sound point. But it needs to be noted here that ABC News moderator Charlie Gibson is repeating a Republican talking point that has been debunked. A capital gains tax will not bring in MORE money to the Treasury. Rather, it will partly pay for itself, and because it is on capital income a good part will pay for itself. But that's still just a part: there is no "inverse relationship".

In any case, this was still an example of Obama's weakness on policy. He's putting liberal ideology ahead of what economists say is efficient (although McCain's gas tax cut idea is even worse).

One of the best articles I've seen on Obamania generally is this one from Rolling Stone, published in February.