IN A RARE SHOW of incisive analysis, Senate candidate John Warner - vainly attempting to quash part of a television interview he'd done for WJLA-TV here - is quoted as saying, "I think I've made a terrible mistake. It could cost me the election. It could mean two years down the drain." That he did - and that it could. More accurately, it wasn't just one mistake; it was a series of revisions and clarifications of his original views as secretary of the navy on the question of how fast efforts to integrate the Navy should proceed:

Reporter Jim Clarke asked the Republican candidate, "Do you think you have black support, and why should black voters support you?" Mr. warner replied ". . . I think it's essential that Virginia's next United States senator represent all Virginians, and I am confident I will receive a substantial amount of the black vote, because if you go back in my record . . . particularly . . . in the Department of the Navy . . . we adopted new policies which made it possible for blacks to, I think, have a greater measure of freedom and job opportunity than ever in the 197-year history of the Navy."

Fine so far. "But," said reporter Clarke, "Adm. Zumwalt says you slowed his efforts to integrate the Navy" - to which Mr. Warner replied:

"No question about it. I don't deny that."

"You did?"

"I think, let's say that we had a clash on the subject, quite clearly. He wanted to go much faster. But if you look at the track record of achievement during that period of five years, I think that it was a very major step forward. . . . It's a very traditional outfit, and you just don't take a hard right or hard left. You sort of move it along and gradually change it, certainly in peacetime."

The next mistake, of course, was Mr. Warner's escalation of this affair when he asked the station to undo the taped damage before broadcasting the show. Not content to leave bad enough alone, the candidate went on to offer a filmsy and doubtful explanation of it all during a supper for 3,500 people held at his estate: "I misunderstood the question. I missed the word "integrate." If you believe that, you have to wonder why he answered the question - and never mind why he answered it the way he did. Richard Lobb, a member of Mr. Warner's press staff, has an explanation that also doesn't bear close scrutiny: It had been a long, fast-moving day, so the candidate "was not as sharp as he normally is, perhaps." His schedule, as released to the press, indicated only one event. Then yesterday Mr. Warner had yet another explanation, to the effect that he really was talking about affirmative-action programs, not integration.

With each revised and extended remark, John Warner sounds more and more like the man he seeks to succeed in the Senate: Virginia's own William L. Scott. And that can't be anything but comfort to Mr. Warner's Democratic opponent, Andrew P. Miller.