• This is a rush transcript from "Your World with Neil Cavuto," December 17, 2007. This copy may not be in its final form and may be updated.

    NEIL CAVUTO, HOST: Senator Joe Lieberman crossing party lines today to endorse Republican Senator John McCain for president, McCain crisscrossing New Hampshire as we speak. The latest FOX News poll shows that he is running second in that pivotal state.

    Why is my next guest trying to help him over that hump?

    With us now, independent Democrat Joe Lieberman from Connecticut.

    Senator, thank you for joining us.

    SEN. JOSEPH LIEBERMAN, I-CONN.: Thank you, Neil.

    CAVUTO: Do you think he's really running for independent, that he's not running for the Republican nomination?

    LIEBERMAN: No. He's definitely running for the Republican nomination.

    I think that nomination is wide open now. He's got some momentum in New Hampshire. And I think he could win it in New Hampshire. And, if he does, I honestly, think he will go on and be the nominee. And that's why I chose to get involved. I have been saying all along that I would wait until both parties had their nominees and then choose which person was — I thought capable of being the best president for the country, because I think this election is too important. We have got too much at stake at home and abroad to decide based on party lines.

    CAVUTO: But let me ask you this, Senator. I mean, he said a lot of good things about Michael Bloomberg in the last debate.

    Michael Bloomberg will be a special guest of mine, by the way, tonight on Fox Business Network.

    But he had also sung your praises. So, he has not been afraid to sort of ruffle core Republican feathers, which makes me think that maybe this isn't about the Republican nomination.

    LIEBERMAN: Well, I can tell you, Neil, that's an interesting theory. But John and I have never talked in those terms. He called me. Why did I do the endorsement today? He called me about two weeks ago. We are very close friends. We have worked together on a host of different issues, particularly national security. We traveled around the world a lot together.

    And he said: You know, I think you can really help me in New Hampshire. If I can win New Hampshire, I can go on and get the nomination. Please think about it.

    And I called him back last week and I said: John, you know, in my opinion, you're best qualified to unite the country to defeat the Islamist terrorist threat and to bring the country together in the way it used to be on foreign policy. And, so, I'm going to help you.

    That's really how it happened. And I...

    CAVUTO: But, as you know, Senator, there's been frustration with the Democratic Party — you, of course, are living proof of that — and within the Republican Party and outside the Republican Party.

    Could you conceivably see a situation next year where a third-party independent candidate, whoever he or she is out there, could do well?

    LIEBERMAN: Well, it's possible.

    And I will tell you why. It's exactly the same reason. I don't think it will happen if John McCain is the Republican nominee, because I think he has tremendous appeal to independents, obviously core support among Republicans. And he will pick up some Democratic support.

    In fact, now on the public opinion polls, he seems to be the strongest Republican candidate in the November election. But the people of this country are fed up with the partisanship. Parties are important, but they're not as important as the country is, the public interest. That's why I said this morning I'm endorsing John McCain, because it's time to put America first again and put the parties second or third.

    But, if you get two candidates for the two major parties who are extremely partisan, and the American people see nothing but gridlock coming ahead, it's possible that a third-party candidate might have a better chance than third-party candidates had generally in American history.

    But my hope is that John McCain wins this party's nomination. And then I think he can go on to unite the country and give us the change and leadership that we need.

    CAVUTO: Would you be his secretary of state?

    LIEBERMAN: I'm happy to — I would do this for any — honestly, I went through so much to get to continue to be a senator.

    CAVUTO: All right.

    LIEBERMAN: That's all I want to do. And I look forward to supporting...

    CAVUTO: Thank you, Senator.

    THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

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