BUSH: You can't be the president unless you have a firm set of principles to guide you as you sort through all the problems the world faces.
And I would be very hesitant to support somebody who relied upon opinion polls and focus groups to define a way forward for a president.
It is -- and so, my question, if I were asking questions to people running for office, what are the principles that you will stand on, in good times and bad times? What would be the underpinning of your decisions?
(END VIDEO CLIP)
GIBSON: What are the principles, and are they constant?
GIBSON: You all have been questioning, as I've watched you campaign, you've all been questioning your opponents.
And I'm going to ask, Senator McCain, you and Governor Romney, because you two have been going at each other, in interviews and in ads about this, of the constancy of your principles or whether or not you look to opinion polls and focus groups to make up your minds.
So let me have the two of you dialogue with each other about this and answer the president's questions, and then I'll bring the other four in and give them equal time.
MCCAIN: The principles and philosophy that I hold, I have held since I raised my hand at age 17 as a midshipman at the United States Naval Academy to uphold this nation's honor; to serve it; call Americans to sacrifice and serve for their nation and defend the greatest nation in the history of the world.
Now we need to restore trust and confidence in government. Now we are in a titanic, transcendent struggle of the 21st century, which we have been discussing earlier.
MCCAIN: I believe that for the last 20 years, I've been engaged in every major national security issue that has affected this nation. And I have been involved in many of the decisions as to how those are handled.
And I again say that I'm glad to know that now everybody supported the surge.
I said at the time that General Petraeus and his strategy must be employed, and I was criticized by Republicans at that time. And that was a low point, but I stuck to it. I didn't change. I didn't say we needed a secret plan for withdrawal.
I said that we can prevail, and as General Petraeus has said, this is the central front in the battle against radical Islamic extremists. We are succeeding.
And I will believe that if we had done what the Democrats had wanted to do, Al Qaida would be trumpeting to the world that they defeated the United States of America.
So my principles and my philosophy are those embodied in those words that we believe that all of us are created equal and endowed by our creator with certain inalienable rights.
MCCAIN: I will defend those. I believe in them. And I believe America's best days are ahead of us.
ROMNEY: Charlie, when I sat down with my family and had the discussion about whether or not to get into this race, we went around the room and each one of my five sons and five daughters-in-law expressed their views. And it's because of them and because of my concern about the future of America that I'm in this race.
I'm convinced that America is the greatest nation on Earth, that we are a good nation and a strong nation. And we are safe and prosperous in part because of our greatness and our strength.