Carville isn't stupid. He sees that Webb and Tester got elected, he sees how powerful the netroots and grassroots have become. He knows we're a huge financial resource for '08 races. He also knows that we're extremely loyal to Dean.
If Dean were to run for president in '08, he'd get a huge percentage of netroots/grassroots contributions and energy, far more than any other candidate, even Obama. Carville knows this. He also knows that his own candidates of choice need that grassroots/netroots money. He doesn't respect us, but he wants our money.
Finally, he knows that the grassroots/netroots aren't exactly subtle. We're a blunt instrument, not exactly Machiavellian.
It's not that difficult to come up with a plan. Call for Dean to be replaced. Let's just say that Dean was already considering leaving. The call to replace Dean would make the netroots/grassroots defend Dean
and reinforce his position of head of DNC. It would make the various state DNC members defend him. It would make it more difficult for Dean to leave. If Dean leaves anyway, Carville can claim it's because he was right about Dean - Dean would appear politically weakened, undercutting any chances of a future run - plus, Carville could then still pound home Dean's promise not to run in '08.
The truth is that the '06 results were a complete and utter vindication of Dean's '04 message, and Carville knows that. Dean would get a lot further with netroots support than he did last time. That scares the hell out of Carville. This isn't about Carville trying to get Ford into the DNC, it's about Carville trying to keep Dean from running in '08.
(Don't say I'm forgetting about Dean's promise - seriously, all Dean would have to do is put up a poll asking the people he made the promise to whether they would like to let him run. It would politically insulate him, and he's done it before.)
And now that I think of it, I think Howard Dean running in '08 is a great idea. Thanks, James Carville! We need to start the call to ask Howard Dean to run for president NOW. Dean has made his point and is vindicated. He could endorse someone that would follow Dean's DNC plan. If Dean wants to keep his promise to stay as DNC chair, he can. But if he could reconsider, then he'd be leaving due to our call, and not because of some irrelevant pundit's caterwauling.