Excerpts from the exchange yesterday between Sen. Sam Nunn (D-Ga.) and former national security adviser John M. Poindexter.

Nunn:

"Admiral, you've used the term during the course of the last four or five days a good many times, the term 'plausible deniability.' "

Poindexter:

"Correct."

Nunn:

"Everybody I've talked to in the intelligence community and around town . . . tells me that the definition of that term is that when you set up plausible deniability for someone . . . they know the facts in question, but they can deny the knowledge, and that the denial is believable. Now, would you tell us whether that is your definition or whether you have some other definition in mind?"

Poindexter:

". . . {In} my {private} testimony on May the 2nd when this issue first came up, I used the term 'deniability' that I wanted to provide the president deniability and insulate him from the decision. Since that testimony, the terminology has been raised in these hearings of plausible deniability, and I have gone along with that definition . . . . It simply is a concept. I think it's open to interpretation. And my interpretation of it is . . . the ability of the president to deny knowing anything about it and be very truthful in that process. He didn't know anything about it."

Nunn:

"That's what Ollie {Lt. Col. Oliver L. North} called absolute deniability. If you don't know, it's not only plausible, it just didn't happen. Is that what you mean, then?"

Poindexter:

"Absolute deniability would be a more accurate description . . . . But because deniability, plausible deniability or absolute deniability are not defined in statute any place, it's obviously open to interpretation."