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This is a RUSH transcript from "The O'Reilly Factor," September 16, 2010. This copy may not be in its final form and may be updated.

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BILL O'REILLY, HOST: In the "Impact" segment tonight: This is obviously a wild political season, and Democrats are on the ropes all over the country because the economy is not getting any better despite the massive spending of the Obama administration. But the Republican Party is split between the traditional GOP people and the Tea Party activists, as we know.

Now watching all this from his perch in Washington, D.C., is Fox News political analyst Charles Krauthammer. So you heard Laura Ingraham and my "Talking Points" on Ms. O'Donnell, Mr. Coons. How do you see this? Who would you vote for if you were in Delaware?

CHARLES KRAUTHAMMER, FOX NEWS CONTRIBUTOR: I'd vote Republican but, you see, I think what Laura is missing the point that what's at stake here is control of the Senate. This is not an ordinary year. This is not an ordinary Democratic administration. This is a Democratic administration with a very ambitious social Democratic agenda. They want to change America. They've had 18 months. They have passed, for example, Obamacare, which will change America structurally and in a way that will not be reversible. Now they have ambitions to do the same with energy, with education, with taxation. They're going to appoint Supreme Court justices.

The paramount objective of any Republican and conservative today is to gain control of one or other of the Houses and stop it, and that's why what's important is winning seats. I think it's a huge mistake to jeopardize a seat in Delaware which was absolutely in the pocket without almost any contention and to jeopardize it with a much weaker candidate, who may or may not win, and I think is overwhelmingly likely to lose.

You know, in ordinary years, sure, you can go by ideology. But Bill Buckley had a rule, which was always support the candidate, the most conservative candidate who was electable. And in this year, that's particularly important.

O'REILLY: OK. But Castle was a guy -- and he was the one that Christine O'Donnell defeated -- who really alienated a lot of conservatives, particularly the Tea Party people because he was so socially liberal and kind of wishy-washy on a lot of the Tea Party issues. And then Sarah Palin came in. So Palin on the program last night, the governor said hey, we would rather have people who are sincere, people who are going to promote what we think the country needs than guys like Castle who really aren't. And, you know, he - they don't trust Castle. They think that he even might go with Obama on a vote or two. So that's why it happened.

KRAUTHAMMER: Look, if he goes with Obama on a vote or two, that's one thing. But you aren't going to have anybody if you support O'Donnell and she loses. It's a completely illogical argument. You're either going to have…

O'REILLY: They don't think she's going to lose.

KRAUTHAMMER: Well, look, but the odds are Castle has run 12 times in Delaware and he's won. She has run twice and lost each time. The Bidens, who own that state, had to groom the son of a vice president to inherit the president's seat, and he flinched. He didn't run.

You know why? Because Mike Castle was the guy that was going to win and he didn't want to be tainted. If the Bidens thought, and they know that state much more than you or I or Sarah Palin, with all due respect, that Castle was unbeatable, I think that's pretty good evidence.

O'REILLY: All right. So that's why Karl Rove was so disappointed.

KRAUTHAMMER: And the fact is this: The only important to vote in the Senate now is the first one who gains control. Do the Republicans get 51 and Mitch McConnell is in charge? Or do you want the Democrats with 50 and with Harry Reid or Chuck Schumer in charge? That's what's at stake here, Bill. It's not a vote or two on the side issue. Of course Castle is a moderate or liberal. What do you expect in the Northeast? That's what you're going to get. You're not going to get a Southern Republican.

O'REILLY: But O'Donnell is a dyed-in-the-wool conservative, and the Tea Party say she can win.

KRAUTHAMMER: Well, let's see it. I'd like to see DeMint, Palin now go down to Delaware and spend a couple of weeks and elect her now. You tell her that she is electable, OK. You got her elected as the nominee; get her elected as the senator. I hope I'm wrong on this. I'd like to see Delaware have a Republican senator and the Republicans have a majority in the Senate. So I hope I'm wrong. Now show me.

O'REILLY: All right. Odds that she wins?

KRAUTHAMMER: 1 in 10.

O'REILLY: Wow. All right, Charles. Thanks very much. We appreciate it.

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