What the heck side of the coin are you arguing?
McCain is more likely to beat Clinton. If Clinton did manage to win, she will not be any more liberal in her intentions that Obama, and likely will realize less of her agenda, because there will not be the groundswell of Camelot BS that would surround Obama.
Therefore, we are more likely to win against Clinton, and if we do not win, I believe the damage will be less than with Obama.