Well, obviously it's because he was the source of the Plame leak, as Kos figured out way back in 2004:

We haven't seen logic that air-tight since we helped this kid in a sophomore year Intro To Metaphysics class. It's almost a shock that it turned out to be spectacularly wrong. And when you consider the intellectual maturity of the Kos comments section, the pieces really begin to fall into place, don't they?

One of the comments from that post talked about how Bush was going to do something crazy to appease the Jews. Firing Cheney was the specific suggestion, but honestly when you're that far gone do the details really matter any more? Regardless, logic on the march.

Anyway, Scooter Libby still hasn't been pardoned by the President, even though Libby was the victim of a politicized witch-hunt aimed at destroying... the President. This seems like a good plan, because the best way to get allies is to abandon them when the enemies they make in your name attack them.

References:
* It was Libby [DKos]

Previously:
* Does Kos Just Get to Make Things Up Now?
MR Has A Question For Democratic Jews: Are You Fucking Retarded?
The Democratic Base Is Proud Of Their Spineless Congresspeople Fighting Nonexistent - But Very Dark - Rovian Plots