I don't understand the approach some Democrats are taking in bringing up McCain's age and as a corollary Palin's (purported) lack of experience. It seems to me that this is a tacit admission on their part that the McCain of today is not the problem; the problem is the McCain of tomorrow, the McCain whose "length of days" might push him down a spiral of some form of dementia or other. Or say McCain's mental faculties don't degenerate, say he dies -- still, the concern is over Palin and her lack of experience than over McCain. Implicit in this objection is a validation of the McCain of today. Apparently, he's ready to lead. Though God forbid anything happen to him while he's leading! We'd be in trouble if something were to happen to the competent, coherent McCain of today.
BTW, I don't have a problem with Palin taking the helm should something happen to McCain. While I'm not hot on the idea of a woman president, my political pragmatism trumps my tentatively-held political principles. Palin's conservatism, however untested she herself may be at this level, topples the liberal alternatives no matter what their experience.
An "evil king" is an evil king. Much of the wicked kings of Israel (and Judah) in the Old Testament were dynastic successors to the throne and thus began their rule with vast experience under their belts. But I'd more readily elect Bristol Palin (given, of course, that she'd fall in line with her mother's policies) than say, King Ahaz.