Another thing to keep in mind about primary vrs general vulnerabilities is that you're both running against different people and courting a different electorate in the General.

On the experience issue, people can reasonably claim that Hillary only really has her six years in the senate as true experience. Even if you claim her First Lady years as experience, it has a distinctly murky feel to it. Edwards, what has he done, aside from being Kerry's VP, and son of a millworker? The people he's running against just don't have all that much experience

McCain, on the other hand, has been around the band more than a few times. You can argue that he's been around the wrong barn, or went around barns the wrong way, but you simply cannot argue that he hasn't been around barns at all. McCain's been in the public eye for, what, fifty-odd years now? That's a far cry from two terms in the senate.

Different people, different field, different battle.