This reflects, I believe, an incredibly damaging mindset that's been crippling the Democratic Party for years and the prospect of excising this mindset is the single most appealing thing about the prospect of Obama being the nominee. Clinton's "street cred" on national security consists, of course, of being massively wrong on the most important national security issue of her career. Paradoxically, a lot of folks find her massive wrongness on this hugely important issue reassuring because they and their friends were also wrong and they view having made the right call to be a suspicious quality. After all, the Iraq War may have led to thousands of U.S. deaths, tens of thousands of U.S. casualties, hundreds of thousands of Iraqi deaths, and millions of Iraqi refugees all at a cost of over $1 trillion and in ways that's damaged the strategic position of the United States, but war opponents were all a bunch of hippies.
Seriously, who thinks this would be a good idea, except Republicans, the few pro-war Dems left out there, and the corporate media?
Hillary rightly or wrongly galvanizes the right-wingers in this country, and would bring them out in droves. She would also undermine the message of change. I strongly believe that an Obama/Clinton ticket would be weaker than virtually any other combination.
Pick someone else without the baggage and negatives. (h/t Atrios)
UPDATE: The Observer also has a piece on whether Obama can afford to eschew Clinton and a so-called "Unity Ticket". The upshot? Yes he can!