This is a partial transcript of "Special Report with Brit Hume", March 30, 2004 that has been edited for clarity.

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(BEGIN VIDEO CLIP)

NATIONAL SECURITY ADVISER CONDOLEEZZA RICE: Nothing would be better, from my point of view, than to be able to testify. I would really like to do that. But there's an important principle involved here. It is a long-standing principle that sitting national security advisers do not testify before the Congress.

(END VIDEO CLIP)

BRIT HUME, HOST: The important principle Condoleezza Rice (search) was talking about with Ed Bradley falls under the heading of what's called "executive privilege." What is it? And what is it supposed to protect?

For answers we turn to our favorite law professor, Jonathan Turley of George Washington University.

So what is executive privilege? What is she talking about here?

JONATHAN TURLEY, LAW PROFESSOR, GWU: Well, courts have spent a lot of time trying to figure out that same question. You could trace executive privilege all the way back to George Washington?

As soon as this Republic was formed with three branches, they immediately started to fight with one another. And that created questions of what could be withheld from one branch or the other.

Executive privilege is really about a comfort zone for the president. It's about protecting a comfort zone where he can speak openly and honestly; bluntly with his closest advisers and not that they will be called to testify before Congress.

HUME: Well, isn't it also about, for them to feel that they can speak candidly to him as well?

TURLEY: Absolutely. And as early as George Washington, presidents were complaining about intrusions. And then with Richard Nixon, we have the modern executive privilege created in litigation, where the court said we recognize a constitutional privilege here of executive privilege. But it is not absolute. It's limited.

HUME: It is something that derives from the concept of the separation of powers?

TURLEY: That's right. And the president's inherent...

HUME: So there's no place in the Constitution where you look up article this or that mentions executive privilege?

TURLEY: Right. It's not mentioned.

HUME: It's a doctrine derived from the basic concept of the Constitution separation of powers.

TURLEY: It's part of that penumbra that surrounds the president.

HUME: Penumbra, huh?

TURLEY: Well, I thought it was a nice term.

HUME: That is a disreputable term and you know it.

(LAUGHTER)

HUME: Anyway, a penumbra is a -- is surround -- is an idea that it is sort of an overall idea?

TURLEY: That's right.

HUME: All right. So the idea is, therefore, that if you -- now this doesn't apply to cabinet officers, right?

TURLEY: That's right, I mean there's...

HUME: Why not?

TURLEY: ... different set of rules. That is there has been a surge in the Clinton administration of this type of privilege for cabinet officers. But generally it is limited to the president. That's where it was designed...

HUME: For the office of the president.

TURLEY: Right.

HUME: That is to say the president and his -- the people he hires who are not, for example, approved by the Senate or don't have to be approved by the Senate?

TURLEY: That's right. And the president has a rather large presidential staff. But there's a distinction between people who go through a confirmation process in the Senate. And people that work for president are not subject to confirmation.

They include the national security adviser. And the national security adviser is really sort of ground zero of executive privilege, because someone like Condi Rice is up to her neck in highly sensitive material and information, from our diplomatic relations with other countries to our priority in terrorism.

And these are all areas that presidents are particularly sensitive about. And sensitive about how the public should learn about it, our enemies might learn about it, or our allies might learn about it.

HUME: Now, there are circumstances under which executive privilege has been overridden by the courts. What are they?

TURLEY: Well, generally, it's overridden on the balancing, that is the courts do not accept the generalized claim of privilege, particularly in the face of an overriding interest in Congress.

So, for example, in investigating crimes, and criminal conduct, the president has found his privilege trumped.

In the Clinton administration, they lost a series of privilege fights, some of which because they were trying really to protect personal matters with this executive privilege.

HUME: In other words, aides were being called to testify about things that happened in the president's personal conduct not policy deliberations.

TURLEY: That's right. And also in some past cases they're being called, for example, to talk about Watergate and criminal conduct. In some cases, aides have been called because they were personally involved in a lobbying scandal. Those were areas where privilege either was waived or it was trumped in court.

You know, presidents hold the privilege. It is an executive privilege. And executive refers to one. It is one executive who holds the privilege and can waive it.

HUME: So she is actually -- as a matter of law, Condoleezza Rice is said to be the one who says to be refuses, when the fact is, it is the president who is not permitting her.

TURLEY: That's absolutely right.

HUME: And theory of it is, one assumes, therefore, is that if she and others like her were able to be questioned in Congress or in other forums, under oath about what they said to the president and then perhaps what he has said to them, that the presidents and those around them in the future would fear making candid, and perhaps politically incorrect, or controversial statements in the deliberations with the president, for fear they'll be spread out on public record before all is said and done.

TURLEY: That's right. And actually, George Bush has a long-standing position on executive privilege.

The view when he came into office, and shared by academics like me, was that executive privilege suffers huge losses under the Clinton presidency. And George Bush came to office with the intention to repair those losses. Even as a governor in Texas...

HUME: In what sense? Now, you said he lost -- that President Clinton lost a bunch of cases on executive privilege. What was the nature of those cases? Is that what he means by the losses?

TURLEY: Right, by the losses because the Clinton administration litigated privilege to a far greater degree than prior presidents. And they lost many of those. They asserted with the first lady and lost it. They asserted it in terms of independent counsels and lost some of the fights. But President Bush actually, back to governor of Texas, he asserted a very strong executive privilege.

HUME: Well, now at the end of the day, if this matter were litigated in court about Condoleezza Rice before this independent commission created by Congress and the president, is he on solid legal ground or not?

TURLEY: I think he is. I think he would win that type of fight. I mean part of the problem is also not just the losses in the Clinton administration; it's books, like Richard Clarke's.

I mean putting aside the merits of Clarke's book and how important those stuff are and it's important, and we'll debate it. But these tell-all books by insiders are creating another front here that is eroding the comfort zone for presidents.

HUME: And inhibiting candid discussion with the president of ideas that may be controversial if they come out later.

TURLEY: That's right. You don't want a president sitting there thinking I'm talking to Brit Hume, I wonder in five years if I'm going to find a tell-all book about what we're discussing now. That's not healthy when you're dealing with lives.

HUME: Particularly in this case when it wasn't five years, it was like two years.

TURLEY: Right. It was a quick turn around.

HUME: All right, Jonathan, thanks for coming. Nice to see you.

TURLEY: Thanks, Brit.

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