I don't think, since the proportional system was put into place in 1970, the race has ever been close enough for superdelegates to make a difference.
I realize that. I also don't think the super delegates would be foolish enough to overturn the clear will of the voters.
It's not set up for conflict like that. I think its set up, so that the establishment - through money, influence and media - can strongly influence which candidate gets picked. Lets' not pretend that voters don't respond to hype, media, and money, as much as they do to issues. I really don't think it's mere coincidence that someone like John Edwards has a hard time raising money and getting media coverage. It's related to a lot of factors, but the fact that he has nowhere near as much establishment support as Clinton or Obama isn't unrelated.