Rove is afraid of Sarah. If she prospers, he will no longer be one of the most powerful insiders.
I think the problem is bigger than that. The problem is that both parties are strongly influenced by the Globalists. I am not saying there is no difference in the parties, but there was a "fix" prior to the last election and there were those (many) in both parties that were in on it. They are scared to death that someone is going to spoil their little party. Palin is not one of them, yet. Nor are TEA Party supporters.
BINGO!
Rove is also likely working for either Romney or one of the other RINO hacks who want to run for president.