... (and it's not much) is: he's not as good a liar as Ari Fleischer. Jon Chait in The New Republic gets many hundreds of words out of exploring that premise:

The New Republic Online: Honest Mistake

For Bush's supporters, McClellan's briefings are a source of despair. "At best, Bush's aides respond defensively," lamented an editorial in The Weekly Standard last week. "At worst, their clumsiness turns a minor flap into a prolonged controversy."

For Bush's critics, they offer a ripe comic target... And yet even the most determined Bush haters will find that, as they watch the hapless McClellan beaten about the head almost every day by the White House press corps, their schadenfreude eventually gives way to pity. It doesn't matter whether you think the media's questioning is fully justified or, indeed, long overdue. You can't help but feel compassion for a man so plainly unequal to the competition.

Really? Maybe the New Republic's self-proclaimed 'Bush haters' like Chait are so easily moved to feel for McClellan, but I don't see why they should be. He knows the job he has, and he does it voluntarily (if less than competently). Why does he deserve any consideration, let alone compassion? This is frankly the kind of say-nice-things-about-your-opponent-when-you-needn't nonsense that makes it effective when people paint 'liberals' as weak and unprincipled. Did you feel compassion for Baghdad Bob too, Mr. Chait?

If some sports team is losing a game badly, yes, you may feel for, even honor, the team getting drubbed. Sports don't matter all that much, so you have the luxury -- even the obligation -- of magnanimity.

Do not confuse the appropriate response to the abuse of power by the world's most potent government and the attempts to lie and cover up on its behalf with the behavior code surrounding football games, you unserious schmuck.

Hey, do you think Chait wrote his "I hate Bush" article way back when so he could now pretend to speak for all people who don't like the administration? I wouldn't even call myself a "Bush hater" (my pet slogan: "Nice guy. Saved Christian. BAD President."), but I hold the Bush administration more responsible for its own actions than Chait.

Yes, Scott McClellan is less good at lying than Ari Fleischer. So maybe congratulate his mother. Don't tell me I should feel for him. He's responsible for his own actions.

Chait said worse things about Dean. Some "Bush hater".