Transcript of Fox News' interview with Defense Secretary Donald Rumsfeld on Special Report With Brit Hume.

HUME: When President Bush makes decisions on building, testing and perhaps eventually deploying a missile defense system, he relies heavily on a man who headed two commissions which studied the need for and viability of missile defense. That man is Mr. Bush's secretary of defense, Donald Rumsfeld, who joins me here now. Welcome, sir.

DONALD RUMSFELD, SECRETARY OF DEFENSE: Thank you very much.

HUME: A big part of the debate to come and the debate past on this issue has been whether such a system, such a missile defense, could work. When you use the word "work," what do you mean?

RUMSFELD: Well, some people mean work 100 percent perfectly everywhere in the world all the time, and I don't. What we really have here is some research-and-development activity, and it's clear that some will work and some won't, and it's unlikely that anything would work perfectly. Most things don't in life.

And so I think that establishing a hurdle that high is kind of unrealistic.

HUME: Well, I don't mean work -- work technologically. But I'm just talking about what's the mission for which you see a missile defense as -- as fulfilling.

RUMSFELD: The mission -- the mission that this administration is interested in is a reflection of the fact that the proliferation of weapons of mass destruction and the ability to deliver them is pervasive in the world, and if a country wants these things, they're going to be able to get them. And it's important, I think, for our country to be able to defend against small numbers, limited numbers of very, very powerful weapons. And that is -- that is what we're about. That is...

HUME: These would be weapons that would be shot -- shot on a missile, on an ICBM, or shot from a submarine, or dropped from an airplane, correct?

RUMSFELD: They -- they -- not from an airplane. They would be ballistic missiles. So, that could be short-range, medium-range or long-range, and they could be shot from land or from the sea, subsurface or on the surface, and unlikely from the air, although it's been done once.

HUME: Right, right. Now -- and this would be a system that would be able to knock them down.

RUMSFELD: Exactly.

HUME: And the highest -- and the highest likelihood of success from what I gather is boost phase: That is before they've even gotten into the atmosphere if it's an ICBM, that you're able to knock it out. That means you've got to forward-deploy this system, correct?

RUMSFELD: Exactly. There's no question but that there are advantages in going after a ballistic missile in the boost phase. The -- it is also possible to go after it midcourse and terminal. But if you think about it, two years ago in Saudi Arabia we lost 24 Americans to a Scud ballistic missile, and during the Iraq invasion of Kuwait. Ten years later, we still don't have the ability to defend against a ballistic missile, notwithstanding the fact that these capabilities are proliferating across the globe.

HUME: All right. Now, what about the argument that, say, China has -- what? -- 16, 18 missiles, something like that.

RUMSFELD: A couple of handfuls.

HUME: All right. And let's assume we're able to build or be on the process of building a system that the Chinese come to think will work at stopping those 18. Won't they, inevitably, as the argument goes, go to 36 or 54, whatever it takes to overwhelm that?

RUMSFELD: The -- the purpose of the system that's being evolved here is -- is to deal with small numbers. The Chinese have already announced that they're increasing their numbers of ballistic missiles.

It's interesting to me: People say, well, if you deploy this, mightn't it cause something else to happen?

HUME: Right.

RUMSFELD: It's also worth thinking about what if you don't deploy it. If you don't deploy it, the reality is, if countries gain these weapons and have them and threaten their use, and we have no defense against them, we only have several choices. One choice is to acquiesce and allow those countries to invade their neighbors or do whatever they want to do, to intimidate us, to be blackmailed.

The other choice is equally unattractive, and that is to pre-empt. That is to say go to a president and say: We do not have the ability to defend against a weapon which could destroy one of our cities or our deployed forces or one of our allies' and friends'. We don't have that ability because we didn't build defenses. Anything you can do is either become isolationist and fall back and go home, or pre-empt. And pre-emption is a very tough call for a president.

HUME: You're talking about a first strike.

RUMSFELD: I am...

HUME: A plane goes in and knock out...

RUMSFELD: You bet. What the Israelis did on Baghdad when they took out the Iraqi nuclear capability many years ago -- and thank goodness they did.

HUME: And you're confident that the technology can be developed that would allow us to defend against small numbers of ICBMs?

RUMSFELD: There is not a doubt in my mind. I have watched the wonderful advances in science and technology over the decades. I think the problem they've had thus far has been basically that the ABM treaty that exists between the United States and the old Soviet Union, two adversaries -- each had the ability to destroy each other in 30 minutes many times over -- inhibits the development of ballistic missile defenses.

HUME: Right.

RUMSFELD: And therefore, no one has done the research that ought to have been done to develop this capability. That needs to be done now and that's what we'll be doing.

HUME: All right. Now, let's -- let's look at another argument and give you a chance to have a go at it that says if Iraq or Iran or someone like that wanted to get the technology, they wouldn't launch it on an ICBM. They'd get it in -- they'd get it somewhere close -- put it on a fishing vessel, slip it near our borders, bring it in a suitcase if they could get it that small -- and make a terrorist attack at us. What do you do to stop that?

RUMSFELD: Well, we're spending -- I don't know what the number is -- but it's over $15 billion a year on counterterrorism activity. And the short answer to your question as to what you do about it is you -- you do a lot of things about it. You protect your forces. You try to have border controls. You try to do all the things you can to dissuade these people from thinking they can be a successful with a terrorist act.

But there are always going to be threats, and they're going to be threats across the spectrum. They may be terrorism, they may be cruise missiles, they may be ballistic missiles. They may be land forces or air forces. And the argument that since you can't protect against everything at everyplace at every moment, therefore, you shouldn't try to protect at all, of course, is not a very good argument.

HUME: Now, the question also is raised about how our allies are likely to respond to this.

RUMSFELD: Yes.

HUME: I mean, President Bush seems unable to say a word that has anything to do with the environment without setting off some sort of paroxysms in Europe...

(LAUGHTER)

... and perhaps elsewhere as well. I know you're going out with missions to important capitals. It's hard to know how this is likely to be received in Moscow. You can guess about Beijing. What about the rest of the Europe? What about London and Paris and those places? Do you expect a warm reception to it?

RUMSFELD: Well, let's take them one at a time. I met with the Australian minister of defense today, and they are quite friendly and open to the idea of missile defense. The president made a number of phone calls this week, including to Mr. Putin in Russia. The consultations are going forward.

HUME: Did he say to Mr. Putin, we are pulling out of the ABM treaty?

RUMSFELD: I was not there for the phone call, but he certainly previewed his speech. And I think his speech is relatively unambiguous, that the treaty is constraining and the United States needs to be able to defend against these kinds of threats.

I think the Europeans will be -- be open to it. I was over in Munich, spoke at the (UNINTELLIGIBLE) Conference in February, and spoke, met with all the various people that come from all over Europe -- indeed, much of the world -- talking about this. And they were -- they were interested in listening. And I don't think there's going to be a -- certainly the Chinese will react negatively, but I think it will work its way through. It takes time to understand it, think about it.

HUME: Secretary Rumsfeld, it's nice to have you. Thank you for your time.

RUMSFELD: Thank you.