You must address America in its entirety, not as a sliver or a series of slivers but as a full and whole entity, a great nation trying to hold together. When you don't, when you play only to your little piece, you contribute to its fracturing.
In the end the Palin candidacy is a symptom and expression of a new vulgarization in American politics. It's no good, not for conservatism and not for the country. And yes, it is a mark against John McCain, against his judgment and idealism.
That's it. And regardless of the basic philosophical value of the conservative platform, it is, at this point, not the same as the platform of the Republican party. And even if it were, there is no one at the helm who appears competent to bring it forward.
To me, that is the greatest argument against their side. Policy is made of compromise, but leadership is made of character. I can let policy differences and disagreements slide, if I know there is an opposition to help clarify and modify them into workable actions; but I want and expect leadership to be apparent in the great task of trying to achieve and implement those actions.