John Gardner, at 65, is the ideal public man. His face has set in the American mind like the plaster of Paris for a pantheon bust, his years as head of the Carnegie Foundation, that finally passes for charm in a lot of politicians.

Amid plaques and busts and cartoons from his years as head of Carnegie Foundation. HEW, the Urban Coalition and Common Cause, John Gardner has his feet on his desk.

He is modest - one hole in the left shoe, two in the right. A touch vain - he has stretched hair across a long run of wide, bald head.And worried - brow lines cluster eccentrically over one eyebrow, the right.

He is worried about everything, it seems.

But what about? His new book, a new-Emersonian testament titled "Morale," stands solemnly above "the grim world around us," warning that "the worst is yet to come" and saying that "with luck, this could be a time of rebirth." This last would seem to imply that all our conscious efforts will not be enough. Gloomy stuff indeed.

Fortunately, Gardner doesn't frighten the reader further by getting specific.

The "crypto-Utopians." for instance. Gardner is very down on their "bitterness and defeatism." Who are they?

"I wouldn't want to try to nail someone to the mat as a specimen," he says, his hands floating through the air with tai chi slowness and a slight tremble.

How about a dead crypto-Utopian then, take your pick from history?

"I'd have to think about that," Gardner says.

Well, if you can't say something nice about somebody . . . And Gardner wasn't in politics all those years for nothing.

"If you look at my record," he says, "you'll see a lot more energy and willingness to take risks than is evident when you sit across the desk from me. There's no doubt that I have seemed to many people who've interviewed me to be rather bland.

Fascinating: the more you listen to Gardner, the more you wonder how he's won his niche as white knight without portfolio. Elliot Richardson's sole rival in reassuring us that decent, handsome men can survive the corrosions of Washington.

"It's just possible," he says, "that you fare beter in this town if you have a bit of the outsider in you. This town envelopes you, it tries to capture you."

Gardner was bred for his role of insider's outsider - one of the more romantic roles the upper classes have to offer.He had an intellectual and sophisticated mother who raised him on books and world travel when they weren't at home in the then-rural village of Beverly Hills, Calif. (His British father had died when he was a year old.)

He dropped out of high school to tour "what we called the Orient, back then" with his maternal grandparents. He dropped out of Stanford to write "the great American novel," which he didn't. He swam a championship free-style on the swimming team, and shunned fraternities. "I'm not an immensely gregarious type, and that's putting it mildly."

After getting his Ph.D. in psychology, with a dissertation called "Levels of Aspiration." Gardner headed East to teach at Connecticut College for Women and Mt. Holyoke. Having married a Guatemalan woman, when the war broke out, he came to Washington in an intelligence post, monitoring Spanish-language radio broadcasts.

He ended up getting a commission in the Marine Corps - "I've always liked small, high-morale organizations" - and a post in Europe with the OSS, precursor of the CIA, and funnel for so many bright, well-bred young men who otherwise might have ended up bored and vestigial.

"There wasn't that much glamor to it," he says, confounding three decades of espionage legend, and thereby demonstrating his modesty or his opacity or both. "It was a lot of work. Very interesting, but very frustrating, sometimes."

Anyhow, an OSS superior's recommendation got him into the philanthropy business with the Carnegie Corporation in 1946. By the mid-'50s, he was its president, a job that gave him impeccable credentials.

In 1965, Lyndon Johnson made him both his secretary at HEW and his token Republican. Gardner left in 1958, reportedly in conflict with Vietnam policy, but retained Johnson's favor as head of the Urban Coalition.

Frustrated with the system, Gardner startled Washington by founding what seemed to be a pin-striped protest group, a lobby for upper-middle-class liberals - Common Cause. The jury will always be out on the effect Common Cause had on all the policies it tried to shape. But it's given credit as a major force behind reform of the House seniority system, the opening of congressional bill-drafting sessions, and the full disclosure of campaign contributions.

Along the way, Gardner has written six books with titles like "Excellence," or "Self-Renewal," and "The Recovery of Confidence." All have been praised for their thoughtfulness, and blamed for being "sermonizing," or "vague."

"You can't be anchored to any absolute. You're just in there trying. I've been in a lot of cities, and you see people fighting for what they want striving . . ."

For no definable reason?

"That's right," Gardner says, without pause.

Is he an existentialist, then?

"I should say that along with man's problem-solving desires is a need for meaning, too," Gardner says.

What meaning?

For Gardner himself, the main touchstone, even since his "Levels of Aspiration" dissertation days, has been "the worth and dignity of the person," he says. "I've been concerned with the fulfillment of potentiality, with renewal, and with morale." This is as specific as he will get. And his books are equally general.

"It's very easy to sit down and say what your values are," Gardner says, "but I wanted to reach a very broad readership."

Surely, though, there have to be good and bad values in the world."

"Absolutely," Gardner says.

How do you tell the difference?

"That's a good question for a philosopher or an anthropologist," he says.

So the former chief of the enormous Department of Health, Education and Welfare leans back in his chair, fiddles with a paper clip, and lolls in these abstractions. An ex-spook! An ex-marine! Can anything rile him into proving his points, snapping out the facts like a Robert MacNamara, a Henry Kissinger?

Then again, at his age and reputation, he doubtless feels little urge to prove anything to anyone.

That confidence is a benefit of his class, of course. You can see it in the nose that vectors nicely over the close but graceful mouth, hear it in the cool grate of his voice as he says: "When you get into the world of action, you find that people have to act day in, day out without conclusive proof of the rightness of their actions."

His actions these days are still considerable. "I'm involved in a dozen projects now that the book is finished," he says. "I consult with Common Cause, the United Way and Aspen Institute. I do a lot of speaking. I'm chairman of the President's Commission on White House Fellows. I'm on the board of Stanford."

He rises from his desk and ducks over to a cabinet. He pulls out a book titled "Know or Listen to Those Who Know," a collection of aphorisms he compiled with Francesca, one of his two daughters. He tosses it on the desk, with only big grin of the last hour.

"You're gonna enjoy that book," he says. "It's the only diverting book I ever had anything to do with."

One of the aphorisms, from Samuel Johnson, reads: "He was so generally civil that nobody thanked him for it."