Sarah Palin endorsed O'Donnell which may have put the candidate over the top in winning the Republican endorsement.

On the night that she won her primary victory, Rove told Fox News' Sean Hannity that O'Donnell was known for saying "nutty things."

"This is not a race we're going to be able to win," Rove added.

Following O'Donnell's loss in the general election, Rove said, "Look, it gave me no pleasure to say she was unlikely to win."

"This again proves a lesson. This is a candidate right on the issues, but had mishandled a series of questions raised by the press early on in the race about her background and previous statements."

Palin called out Rove by name after O'Donnell's loss. "I look forward to Karl Rove and others looking at...reporting that exit polls are showing that Mike Castle would have even lost to Chris Coons," she said on Fox News. "There was never any guarantee that a hard-core conservative would win in a deep blue state like Delaware."

But Rove's viewpoint may be representative of other establishment Republicans who weren't fond of O'Donnell.

"I think Delaware was a missed opportunity to have a really good United States senator, Mike Castle, and that's why I endorsed him in the primary," New Jersey Gov. Chris Christie said on NBC Sunday.

Rove and Palin also clashed over the former governor's new reality show. Rove told the Telegraph that he failed to see how a reality show helped Palin make a serious run at the presidency in 2012.

"There are high standards that the American people have for [the presidency] and they require a certain level of gravitas, and they want to look at the candidate and say 'that candidate is doing things that gives me confidence that they are up to the most demanding job in the world,'" he said.

The next week, Palin compared herself to another entertainer, President Ronald Reagan, to defend her new show. "Those standards have to be high for someone who would ever want to run for president like, um, wasn't Ronald Reagan an actor? Wasn't he in Bedtime for Bonzo, bozo or something? Ronald Reagan was an actor," she said.

"Now look. I'm not in a reality show. I have eight episodes documenting Alaska's resources, what it is that we can contribute to the rest of U.S. to economically and physically secure our union, and my family comes along for the ride because I am family, family is us, and my family comes along on the ride to document these eight episodes for The Learning Channel. ... So Karl is wrong right there in calling it a reality show," she said.