AT THE END of Walter Mondale's campaign speeches these days, the ones that hype Jimmy Carter's honesty, compassion, intellect and discipline, the vice president pauses. Like a supplicant, his chin's rounded edge drops onto the uniform blue oxford shirt. He pleads slowly, "Send this good man back." Then, without missing a beat, Mondale sheds the studied tone. "And when you do, guess what else you get," he says, his arms leaving the podium to form a scarecrow arch above his thick, wheat-and-silver hair. Suddenly, Walter Mondale is Steve Martin, the tease and the gestures perfectly timed. "You get the vice president," he says, as the applause and laughter crescendos. "You get Walter Mondale."

Like every display of political burlesque, this one contains a multilayered message: Mondale, the good-natured fellow and loyal campaigner, wants to leave his audience laughing. It's the veiled hint that Mondale, the steady, ambitious politician, wants the audience to look closely because his own turn might be four years away; and it's the pointed reminder by Mondale, the vice president, that he is more than a ceremonial stand-by. "Next to his own family, I think I know this man better than anyone else in the country," he says of Jimmy Carter.

Walter Mondale, along with Rosalynn Carter, has become the principal campaigner for the Carter-Mondale re-election bid. During the last three months of international crisis, while President Carter has opted for the advantage of a capital cloister, Mondale has spent nearly 40 days on the road pushing the administration's record in the early tests of strength as the president's surrogate. Yet this is more than duty work for the boss, more than verbal deposits on four more years of work. This is Walter Mondale, fighting for his own political identity. This is Walter Mondale, battling the insurgent cry that he has lost his liberalism. This is Walter Mondale paving the way for a possible presidency of his own, the temptation of every vice president.

He has been so adept that the morning of the Iowa delegate selection, an NBC reporter called Mondale "Carter's secret weapon." After the State of the Union address the president attended a small, thank-you party at the White House for the Iowa caucus workers. He spoke of Mondale's indispensability, saying, "The people of Iowa feel secure about me because they feel good about Mondale. And they feel confident because if the need ever arose they know Mondale would be a good president." Neither Mondale nor any of his aides were in the room. Heading to Hibbing

"I smell victory in this room" shouts a dark-suited Mondale, vigorous on his last campaign of a 15-hour day, his face flushed. The New Hampshire hotel room is packed with the faithful, the first group of the day that doesn't need a brass band for warm-ups. "So often, as in the past, New Hampshire is going to decide where this nation is going to go. My message for you tonight is one of hope, against over-confidence," says Mondale slowly. A woman halfway back in the room nudges her male companion. "See. I told you he sounded like Dustin Hoffman in 'Little Big Man'."

At this moment, however, Mondale is delivering a warning. In 1978 this state lost a three-term Democratic senator, Thomas J. McIntyre. "Start tonight with every friend you can find, raise the money if you can find it, extend your influence as far as it will go, tell about this fine president we've got and let us make sure that on election night we are not sorry again."

It works. The crowd is souped up. And Mondale needs a full 15 minutes to leave the room. Then he heads into the clear indigo of the New England sky for Minneapolis and real roots.

"When the nails crack in a house, then you know it's cold." This is Mondale reassuring the reporters on his plane who have just braved a light snow in Minneapolis and are heading north to Hibbing where the weather is rumored to be 29 degrees below zero. Never mind. The vice president, his hands tucked into his pants waist, is extolling the virtures of iron ore and taconite, the be-all of Hibbing.

Standing in the aisle, in cracked tennis shoes, Mondale tells the story, perhaps for the sixth time in 10 hours, about the guy who broke his nose during the high school basketball game, an adolescent turning point used as a speech story. "The last time we were in Minnesota the guy showed up. Now he's 300 pounds, wears bib overalls, is a sheep herder and I bet he's a Republican," laughs Mondale through thick overlays of Midwestern by-gollys.

He has a theory about the happy politican. "I think I learned a lot from Hubert Humphrey about the necessity of having fun in politics," says Mondale, over coffee in the forward section of his plane. "There's no sense in being a grind, a scowl, people don't like it.It's no damn fun. It isn't necessary. People want to have a good time. Public happiness is a very important part of leadership and is what makes it worthwhile."

Add to this exuberance a megaton of loyalty. This is a loyal vice president, a loyal surrogate, a trait that though the times, the policies and the presidents have dramaticaly changed, echo his mentor Humphrey in many ways. This unabashment might endanger a solo act four years from now. "Mondale is too loyal, even Hubert rolled his eyes once in a while," says long-time Mondale watcher and editorial writer William Sumner of St. Paul. And while Mondale is trying to have it both ways -- serve the president and please his traditional constituencies -- he tells a friend privately, "Sometimes you have to swallow your pride."

For Mondale's part, he seems to thrive on the campaigning, particularly the niceties. And that's a sign of growth and accommodation from a man who, during his first year as Minnesota attorney general 20 years ago, decided a serious politican didn't smile. Now he's an anecdote machine. This is a politician who dropped out of his nascent presidential try in 1974 because he didn't like the rigors. Now he fairly bounces out of Air Force Two, handshake and quip ready. While he blasts through speeches, telling the worn story about his primary teacher, who told him he would never be second to anybody, evoking Humphrey's name to undergird his progressive reputation, rattling off the administration's achievements, he looks content. Even in the privacy of his plane, when he occasionally bemoans a testy question, he never loses his enthusiasm for the crowds. "I've always thought you could learn more from two days of campaigning than a $20,000 opinion poll." y

What he doesn't enjoy about campaigning, he simply doesn't do. Or does with obvious reluctance. Thus the criticism of his boss' principal opponent, Sen. Edward Kennedy, a former Senate ally of Mondale's, has been selective. There isn't the jugular lancing one would expect with such high stakes. "I've never run a negative campaign in my life. I hate to mention my opponent's name. I think he ought to pay for his own advertising," says Mondale. "People don't like negative campaigners. They want to know what you're doing."

He is also well-aware that too harsh criticism of Kennedy might alienate Mondale's traditional constituency of liberals. But this personal strategy feeds new ammunition to his detractors, who for years have been accusing him of having no guts. Before he tested the presidential waters five years ago, Mondale was known as a strong busing proponent. A friend asked how he could be so staunch when other liberals were waffling. "They are all trying to be president, they are all cutting corners," said Mondale. Later when his views were modified the friend brought it up and Mondale replied, "When you are running for president people listen to you more.'

How much of a liberal Mondale is is the question dogging his heels right now. In the Senate he was considered a champion of the underdog. His credentials included his placement on Richard Nixon's enemies list but were marred by his late opposition to the Vietnam War. But the skeptics, who regard the Carter White House as conservative, even nonideological, wonder how much Mondale has compromised. "A vice president is not a free man. I wouldn't sum up Fritz' liberalism based on the last two or three years. If he was the top, he would be different, he would be the old Mondale," says Steven Schlossberg of the United Auto Workers, a Kennedy supporter.

"They will say that but they are wrong," Mondale says. The harsh, Midwest staccato speeds up. "And not only are they wrong, but if the only way you can be a progressive is to oppose adequate national defense, there will be no progressive movement left in America . . . The most basic progressive need is a free society and a stable and secure society. With the Russians pulling their little games, building up, we have to respond. I regret we have to spend that money but on the other hand the realities of life are such that we have to." Coming Back to the Fray

While his liberal credentials are under the microscope, so are the dynamics and influence of his vice presidency. In his relationship with President Carter, Mondale has been described as a "private catalytic agent rather than a public power broker." In that capacity over recent weeks he brought back to the Oval Office, according to White House insiders, the opinion that the farmers wouldn't abandon the administration over the grain embargo and that inclusion of women in the draft registration would be an asset to the administration's stand on the ERA.

While Mondale's self-defense is fervent, he refuses to discuss specifics, suggesting that anonymity is one of a vice president's pains. "I believe if I am going to be the confidential advisor of the president . . . I don't believe I can keep a win/loss record and go out and say so," says Mondale. Yet wouldn't some evidence of his victories and disagreements still his detractors? "That's a cross I have to bear," he says evenly, "and gladly."

Those questions about Mondale's integrity and influence drive him up the wall. Last fall he exploded over a James Reston column that accused him of selling out for political expendiency. Since he first worked for Hubert Humphrey's election as U.S. senator in 1948 and wore a "William O. Douglas For President" button, Mondale has been involved with the progressive movement. The son of a Minnesota farmer, Theodore Mondale, who had a religious experience when he was plowing and turned to a itinerant ministry, Mondale grew up in a politically-aware, hard-working, loving and poor family. In high school, where his football skills earned him the nickname "Crazylegs," Mondale formed a political group named the Republicrats, a signpost of his future compromise skills. Because funds were scarce, Mondale dropped out of Macalester College in St. Paul after two years and later finished undergraduate school and law school at the University of Minnesota. In 1960, at age 32, Mondale left his law practice to accept an appointment to become the state's attorney general. Four years later he was appointed to Humphrey's seat in the U.S. Senate.

From the inception of his national political career, Mondale worked valiantly on consumer, hunger, poverty, civil rights, education and children's issues. He led the hard battle on the Child Development Bill which Richard Nixon vetoed. "He really pushed very hard and was viewed as a champion of children's needs," says Marian Wright Edelman of the Children's Defense Fund. Now she views the administration as "foot-dragging" on these same issues. When his own bid for the presidency seemed futile, he learned to joke about having one percent recognition and challenged "don't know" to a debate. But he tagged his campaign trips "death marches" and to the surprise of most of his friends, after 15 months pounding the country's byways, dropped out. Then he wrote a book called the "Accountability of Power," his reaction to Watergate-injected disillusions of politics and led a successful revision of the filibuster laws in the Senate and lost an effort to scrap the Space Shuttle. When he first went to Plains to meet with Jimmy Carter, he took his book and Carter's "Why Not the Best" and compared them. He decided compatible grounds were present. But Mondale was nervous right up to the telephone call from Carter, checking to make sure his telephone was not dead.

The friends who have known him since he was appointed Minnesota attorney general insist he hasn't changed and is as diligent and cautious as always. The detractors point out he hasn't been tested, since each election to a post followed an appointment.

When he relaxes, the serious and the light side tug at one another. What the lean, ruddy face, the crystalline blue eyes, the lines that mark his 52 years show is his stamina. Relaxed, in his tennis shoes, a glass of wine and a cigar, and occasionally a pizza for the travelers, he talks about power, noting he doesn't know if he will keep coming back to the fray, like Gerald Ford, or discusses the lessons of the French Revolution for today's Iran.

"Don't let anybody tell you he's a lightweight," says speechwriter Marty Kaplan. "Once he told me, 'Put in that quote about Mazzini and Cavour that appears in Trevelyan's biography of Garibaldi.' I just looked at him." His reading lists are influenced by historian Barbara Tuchman. "What I like is that our conversations indicate he understands, not just reads," says Tuchman. "I have popped into his office once or twice. We disagree on my theory that the president should have only one six-year term. He believes re-election demands accountability but I think the presidency should be restructured, It's too much for one person to do and do it intellectually." Mondale sent her a photograph of the president reading her history of Palestine, "Bible of the Sword," with an inscription, "We always read our leader for breakfast." But some feel the down-home ease with the public, and especially the press, is all calculated, the cosmetic baggage of a striver. After the staff pumped a reporter with glowing stories about Mondale's interest in water projects, the reporter asked him about it in an interview. Mondale looked blank, finally says, "give me a clue." Some have heard him turn down invitations saying "it wouldn't be vice-presidential." In the Sparring Role

Within days of the inauguration of Richard Nixon in 1969, the new administration moved to ease the affirmative action guidelines in the textile industry. Mondale, recalls one staffer "went berserk." He called for hearings and Ted Kennedy held them. That's the way it used to work: not the best of friends but the most dependable of allies.

Now, one of the interesting scenarios of the campaign, starting with the opening shots at the Democratic Mini-Convention in 1978 in Memphis, has been the byplay between Mondale and Kennedy. Months ago, when the press signaled out Mondale for the Kennedy sparring-partner role, he got outraged and pretty much has stuck to the soft-pedal. Mondale assiduously refuses to discuss Chappaquiddick. He says Kennedy is a friend. And only near the wire of a primary, will he sharpen his rebukes. A friend of both says, "It's fascinating to watch because the things Fritz would naturally espouse have been taken by Teddy."

But Mondale's self-instituted Operation Hold-Off has been derailed several times. In Iowa the two crossed words over patriotism. When Kennedy announced he wasn't supporting the grain embargo, Mondale said support of the move "was the patriotic thing to do." Everyone read that as a slap against Kennedy since Mondale wouldn't clarify the suggestion. A very upset Kennedy said, "I have too high a regard for Vice President Mondale to question his decency or his patriotism . . . I don't think that I or the members of my family need a lecture by Mr. Mondale or anyone else about patriotism."

By the time of their face-to-face showdown in Waterloo, Iowa, both teams had decided to play the episode lightly. With their respective camps from the Black Hawk County Democrats cheering, Kennedy gave Mondale a red jersey of the New England Patriots. "I present it as one good patriot to another," said Kennedy. They laughed publicly. Last weekend both men addressed the leadership of the AFSCME union. Kennedy was wildly cheered, observed Jerry Wurf explainng, "then Mondale came on talking about those who want power and those who have it. And asked the leaders if they always had the support of their rank and file. It was a terrific approach." Taking the Gamble

At the Mondale home, at the time his name was a vice-presidential possibility, the people around the kitchen took a vote.Four to two against Mondale taking on the job. Mondale voted against.

In the past the vice presidencies were passages of waiting, exercises in wounded egos, lessons in anguish. But, as soon as his name was floated, Mondale, the steady climber and pragmatist, sat down to map out a strategy. Yet he remained skeptical. But the Mondale and Carter insiders say the plan has worked. Says Frank Moore, the chief congressional liasion, Mondale is in and out of everything, everyday. In the meetings the president always checks with him last." When a constituent sent Mondale a tape with vice-presidential song, Mondale played it so loud, the president came in from the Oval Office. He sat down, listening and wearing another gift of Mondale's, a tri-cornered Spanish policeman's hat.

Perhaps it was his intellectual curiosity, sparked by a conversation with his Minnesota elder and former vice president Hubert Humphrey that made him take the gamble. "In the spring of 1976 we sat down with Humphrey in the Senate dining room. And Mondale asked him, 'Is this something I should be interested in?' And Humphrey said for all the difficulties, for all the abuse, it was the most enriching experience," recalls Richard Moe, Mondale's chief of Staff. "Mondale was very moved because most of us had the view if Humphrey had never been vice president, he would have been president. We had looked at it as a step backwards."

Sometimes Mondale, say the political observers, has been a full partner and on other occasions a silent partner. On domestic issues, for starters, his staff says, he argued for a forceful administration brief in the Bakke case, fought during the 1980 budget process for Head Start, Legal Services and helped win union support for the bail-out of Chrysler Corporation.And Joseph Califano, a good friend, says that elementary and secondary education programs received a 40 percent budget increase because "Mondale fought for it every inch of the way."

In foreign affairs, a relatively new mission for Mondale, talks with Israeli Prime Minister Begin and Egyptian President Anwar Sadat in July 1978 have been credited by Begin as an important start for the eventual Camp David accords. In early 1977 Mondale sat down with the testy John Vorster, then prime minister of South Africa, and articulated the adminstration's innovative policies toward Southern Africa. In answer to a press conference question at the conclusion of the discussions, Mondale was asked if the United States position was "one man, one vote," and he said yes. Mondale viewed that remark as one of his public mistakes. "That was used by the opponents of reform very effectively. I didn't mean it that way. Our basic recommendation was that you meet with the blacks and whites internally and work together." Critics of Mondale see that retreat as an example of lack of courage.

Repeatedly the men and women around Mondale say that Mondale the vice president operates like Mondale the Senator, which didn't change from Mondale the attorney general.Which is to say, Mondale works like a lawyer. m"Mondale has always burned out staff people," says one, explaining his work method. "He's one of those people who press the edge, love information, look at each policy issue like a case. He studies the problem, the chance it has, how to win the problem. He is interested in how others think but somewhere along the line he makes up his own mind." The Best of Times

In many ways, these are the best of times for the Mondales.He is making more money than before, "$75,000 compared to $44,476 in the Senate with perks such as the mansion and a limousine." Their oldest son, Teddy Mondale, is on a path of education and politics his father approves of. "For years he was into motorcycles and didn't do too well in school. Now he's studying political science. He showed up today in a three-piece suit. It's amazing," said Mondale.

In a candid moment, the vice president also says his wife's lifelong interest in the arts, which blossomed into a full-time job, has made her a different person. "She has prospered immensely," he says adding kiddingly, "But she's still tight. She didn't want to have a moving van from the trip from Lowell Street to the Naval Observatory."

Officially Joan Mondale, a trained art historian and author of a book, "Art in Politics," is the chairperson of the Federal Council on the Arts, but she has expanded that inter-federal-agency role into a sounding board for all areas of art problems and projects. "I have a job now, I never had a job before. I was lady housewife, mother stay-at-home, PTA volunteer worker, brownie maker. I really like it, it came at the perfect time in my life," says Joan Mondale. And she does feel better, she says, citing "better clothes," and weekly trips to hairdresser as ego boosters. But, ironically, their new activities are hampered by some loneliness. Now the vice president flips wistfully through baby picture albums some evenings, regretting the lost moments, with Teddy, 22, Eleanor, 20, and William, 17. Fueling the Fire

Most surprising, says Walter Mondale, have been the pressures. "Of course, I knew that intellectually, but to participate in, to be around and feel the heat," says Mondale. "To get up on a Sunday morning and discover the Iranians have 50 American hostages . . . or attending a state dinner when a U.S. helicopter gets shot down in North Korea . . . well you just never know where the next ones are going to hit."

At nearly every stop, there's an aside about how Mondale will return as a presidential candidate in four years. Mondale fuels the fire. "I know there's a movement for an Irish vice president. But I told Hugh Carey and Pat Moynihan I can't make a committment for four years." In his office Mondale avoids the discussion of the future."People think I'm coy if I say I don't know but I really don't know . . . I certainly am campaigning for this time, I am campaigning for Carter." Later he jokes about the future containing 20 years of delayed fishing with his fishing cronies who have renamed a northern Minnesota waterway, Lake Termite, Lkae Mundali, the accent Italian.

What happens if Carter and Mondale are swept away in July or November? The vice president laughs. It's not in the Mondale cards.

While the fire in his West Wing office crackles, he discusses the vice-presidency. "The low point for me was when we were in that deep trough in terms of public sentiment . . . One of the reasons is when the president is alone, being measured against perfection. It's very hard to be perfect. But once those who want to take his place have to stand up and answer what I call presidential questions, what they would do under the same circumstances, Afhanistan and so forth, then I think the comparison has consistently worked to the president's advantage."

What might make it easy for a possible future run is Mondale's view that the American public isn't as cynical as it once was. "Particularly in the last year, I sense a resurgence of trust. For a while you would go and try to talk about the energy crisis before the gas lines. People would stand up and ask questions, and if you got under it, the guy was really asking you if you were a liar. It all began with a sense of what kind of mendacious corner is this fellow coming out of . . . There is little more balance now, and that is helping the president."

But is it helping Walter Mondale? "Sure you feel better."