I'll blame him for attacking the Republican candidate immediately following her primary win, and for quite some time thereafter. The Republican voters of Delaware had spoken. His fit of pique will cost him down the road. He's verging on anathema and deservedly so.
Rove can suck it.
Yeah, but that's not the view of Christine O'Donnell, who didn't support the GOP nominee after she came in 3rd place in the primary. She ran a separate campaign in the general.
So it's not like she had much room for criticism.