Barack Obama is perhaps the only presidential candidate who could have wrested the nomination from the once-inevitable Senator Clinton -- who was supposed to make history by being the first female to win a major party nomination. He's young, eloquent and an even more dramatic "first" than she would have been.
In turn, Hillary Clinton is almost the only active politician in the Democrat Party who can't be overtly bullied and pushed from the race to clear the field for Barack, now that it's obvious to just about everyone that she doesn't really have a shot at winning. That's owing to her status as the wife of a former president.
It's remarkable to see how the "firsts" in the race have been playing out, often to the detriment of both sides.