I think what they (MSM diptards) are really afraid of is not necessarily that Palin could not step in if McCain could not continue and or finish his term. I think they see the groundswell of support for this hot outsider that electrifies the GOP base and because of her age could be the female Reagan for the 21st century. Only time will tell but I think Palin could be a serious contender. A successful term as VP and a one term McCain could position her pretty well.
I think you've hit the nail on the head. - By picking Palin, McCain has captured the White House for the next 16 years. It is theirs to lose, but the wackos are out of the election at this point.