Obama wasn't ready to be beholden to Hillary
And any of her buddies in Washington.
Hillary had been bought and paid for by the very same people Bush and Cheney have been working for. It wouldn't have been any different if he'd picked her. There would have been no change.
And she's a ballsy lady.
Imagine saying "no" to Hillary in time of crisis?
He doesn't need the headache (or the emasculation).