This is a rush transcript from "The O'Reilly Factor," April 1, 2009. This copy may not be in its final form and may be updated.

Watch "The O'Reilly Factor" weeknights at 8 p.m. and 11 p.m. ET!

BILL O'REILLY, HOST: in the culture war segment tonight, to celebrate "The Factor's" 100 months at No. 1, I've been doing a lot of media this week. And last night I visited David Letterman. Now, some of you think I'm crazy to go on that program because Dave is a committed liberal, but I like the joust.

Here are some highlights.

(BEGIN VIDEOTAPE)

DAVID LETTERMAN, HOST, CBS'S "THE LATE SHOW WITH DAVID LETTERMAN": When I look at that 100 months, how many years is 100 months?

O'REILLY: Eight and a quarter.

LETTERMAN: Wow. Nice going, No. 1 in cable news, and congratulations. Take us through the history. Were you always news commentary or were you a reporter of hard news?

O'REILLY: I was a reporter. I started in Scranton, Pennsylvania, and worked my way up. Worked at Channel 2 in New York. ABC News, CBS News, and I did "Inside Edition," one of your favorite programs.

And then I went back to school, went to Harvard, got a master's degree in public administration, designed "The Factor" in Cambridge, Massachusetts. Came back, they hired me at FOX. And here we are.

LETTERMAN: When you say working your way up, does that really apply to FOX? Come on.

Let's talk about this. The big thing with Rush Limbaugh, the new face of the Republican Party. Now, how did that happen? Is that a good thing? Is that what they need now? And what's going on there?

O'REILLY: Well, I think it was a Carville, James Carville — you know James? He has been on this program. And somebody else, they said well, let's throw this out there that Rush Limbaugh is running the Republican Party. And the media ran with it, and so there it is.

LETTERMAN: Is he, in fact, the titular head of the Republican Party? Does he represent the constituents?

O'REILLY: I don't believe so. I don't check in with the Republican Party very often, so I don't think so.

LETTERMAN: And what was the deal where the Republican Party in the face and the gesture of Richard [SIC] Steele, offered Rush Limbaugh an apology?

O'REILLY: I don't think they want to offend Rush Limbaugh. He's got 15 hours of air time a week on the radio. So I don't think any Republicans or conservatives want to offend the man. You're making a big deal out of nothing here. I don't think this is an important thing for the folks.

LETTERMAN: I was excited about it. I wanted — I want Rush Limbaugh to be the new face of the Republican Party.

O'REILLY: Why?

LETTERMAN: Well, he's tubby. For a long time, he had his housekeeper buying illegal drugs. And I thought, well, if this is what the Republican Party needs, there you go.

O'REILLY: You're signing up? You're on board. Do you really think it's nice to do that to Limbaugh, though? I mean, really, this is a serious question. The — they set him up as a straw man. Right. Nobody takes this seriously.

LETTERMAN: I think he set himself up, didn't he?

O'REILLY: Why? He's a radio talk show guy. He goes on the radio, just like you go on TV. He does his show. You either like it or you don't. Nobody forces you to watch or listen to you or Limbaugh. Why cheap shot the guy? I mean, why bother?

LETTERMAN: That's a good question. Oh yes? Oh yes? Whatever.

Here's what I've always thought about Rush Limbaugh, yourself, and your buddy Glenn Beck even admitted this.

O'REILLY: You think we're the same, Limbaugh and I are in the same...

LETTERMAN: Please, will you just give me a minute?

I always thought that Rush Limbaugh could have been a TV weatherman, could have done sports. He could have hosted a game show, but somebody said, "Rush, we've got this — we need a right-wing commentary niche."

"Oh, yes, I can do that."

O'REILLY: Do you know him?

LETTERMAN: I've met him a couple of times. He's been on the show.

O'REILLY: Didn't you used to be a TV weatherman?

LETTERMAN: Yes.

O'REILLY: OK.

LETTERMAN: But now I'm not the face of the Republican Party.

O'REILLY: You're not? I thought you were.

LETTERMAN: But it just seems to me like he's too smart to believe what he's saying. And I feel the same way about you. You're too smart to believe what you say.

O'REILLY: Whoa! Wait a minute, wait a minute. Now, hold on.

Don't make me come up there.

LETTERMAN: Yes, don't make him come up there.

O'REILLY: Give me one example of something that I've said that I'm too smart to have said, just one.

LETTERMAN: You're going to — you're going to boycott Sean Penn movies.

O'REILLY: Yes, I don't — that's a good one, Dave. And I appreciate you having a discourse now. It's my 10 bucks, right? I can go see what I want, right? Whoa, let me talk!

All right. Now, this guy runs down to Venezuela and does Lambada with Hugo Chavez. OK? I don't like Hugo Chavez. I think he's a tyrant. So I'm going, "I don't really want to spend 10 bucks on this guy."

If Clark Gable, Dave — and I know you feel the same way — if Clark Gable had cozied up to Francisco Franco in the '30s, I wouldn't have gone to see "Gone with the Wind."

LETTERMAN: But strictly speaking, one of two things. You're boycott of Sean Penn. When is the last Sean Penn movie you saw, period?

O'REILLY: I saw "Mystic River," the Clint Eastwood movie. Excellent film.

LETTERMAN: OK.

O'REILLY: And he's a good actor, by the way. I'm suffering here for my art.

LETTERMAN: Now, let's talk about your buddy Glenn Beck. There was a piece on him in the Times the other day. And he said what I think coalesces this whole deal.

O'REILLY: Which deal is that?

LETTERMAN: Which is you're too smart to say the things you say.

O'REILLY: Everything I say I believe. And I believe everything Beck says he believes.

LETTERMAN: Yes, but do you — what percentage of stuff do you make up?

O'REILLY: None. And if I make anything up, they just rip me up in the New York Times or whatever. I mean, we have a very good research staff, just like your staff. Very good. They find out the facts. We come in, we present them, we give an opinion. We bring on an opposing point of view. That's why we're No. 1, Dave.

(END VIDEOTAPE)

O'REILLY: That's why we're No. 1, Dave. Eighteen-minute segment last night on that show.

Content and Programming Copyright 2009 FOX News Network, LLC. ALL RIGHTS RESERVED. Transcription Copyright 2009 CQ Transcriptions, LLC, which takes sole responsibility for the accuracy of the transcription. ALL RIGHTS RESERVED. No license is granted to the user of this material except for the user's personal or internal use and, in such case, only one copy may be printed, nor shall user use any material for commercial purposes or in any fashion that may infringe upon FOX News Network, LLC'S and CQ Transcriptions, LLC's copyrights or other proprietary rights or interests in the material. This is not a legal transcript for purposes of litigation.