would never entertain Hillary as the VP is because it negates his key argument about judgement regarding the Iraq war. He's positioned himself against Hillary and McCain this way and a key part of his strategy against McCain's tactic of painting him as inexperienced is to counter him the same way he's countered Hillary. If he has Hillary as a running partner, he can't quite use that argument anymore as Hillary will be "a heartbeat away" from the big chair.

Hillary on the other hand if she were to win could select Obama since an inexperienced VP is not a major impediment to election (Quayle), it is even seen as a "seasoning" position, a place to plan dynastic succession to some.