I would agree that Hillary! could never win a conventional election. The more people see of her, the less they like her. Therefore, her only hope is to be named the candidate with only a few weeks to go before the election.
By late September, the negatives on both George W. Bush and John F'n Kerry are going to be through the roof. If Hillary! can replace Kerry at that point, she will pick up all of his remaining support, all of the Clintonista vote, all of the people who want to "make history" and all of the people who are repulsed by both Kerry and Bush at that point. All of these added together is at least half the vote.
Not even Hillary! could screw it up. The only way to stop it is to prevent it from happening.