Ten years after Mo Udall's presidential campaign, the ballroom of yet another "crummy Holiday Inn," as Udall puts it, is filled with survivors, come to reminisce about that crazy time when they lurched from primary to primary in Udall's decrepit prop plane.

It was called the Bazzler Bomber (for the Bazzler charter service), rumored to be Willy Brandt's Air Force One and looked like the plane that carried Ingrid Bergman out of Humphrey Bogart's life in "Casablanca." While Jimmy Carter, the prosperous front-runner, streaked ahead by jet, Udall bumped along in the Bomber, stuck firmly in second place.

Standing at the mike a decade later, Udall welcomes "all you losers. Looking at this crowd, you can see now why we lost the damn thing. Anyone who can find merit in a candidacy that could not even beat Jimmy Carter is one I should not be associated with."

The laughs come, just as they had during the campaign, and, as usual, Udall is leading them. Not only does he joke about being "Second Place Mo" now, he could joke about it then.

"All I had to do was win one," he remembered recently, sitting in his congressional office. The Wisconsin primary had been his hope of hopes. ABC called it for him and so did the first editions of many newspapers, and Udall, king for a few hours, exclaimed, "How sweet it is!"

But ABC was wrong; the last votes were counted and Carter squeaked ahead. The next morning, reporters waited at the Bazzler Bomber wondering how Udall would react. Looking down from his 6-foot 5-inch height, Udall pointed to one reporter's notebook and said, "You know all those times I said 'win' last night? Well strike that and insert the word 'lose.' " Wit in Adversity

A telltale purse-lipped pucker of a smile begins to form when Rep. Morris K. Udall is about to launch into an anecdote or one-liner. As it has for many humorists, joking became his shield early in life.

Udall was barely 5 when a playmate, trying to cut a string, slashed upward with an old rusty knife, striking Udall in the right eye. The eye became infected and had to come out. It was years later, in the Army, before he got a glass eye that fit properly and actually matched his good blue-gray one. Growing up was hard, he remembers: "Kids could be cruel, and I made an attempt to save myself from that. I joked about it even then. I think a lot of my humor is self-defense." He went through high school without a single date. "I was 6-foot-4 and weighed 150 pounds." Udall smiles. "My football coach used to say, 'If you drink red soda pop you'd look like a thermometer.' A tall skinny kid was bad enough, but to have one eye!"

He overcame an ugly duckling adolescence, but the plagues continued. After losing to Carter, he fell from a ladder while working on his roof and broke both arms. He contracted peritonitis after his appendix burst. Now Udall has Parkinson's disease and he is still self-medicating with humor. "When I was first diagnosed as having Parkinson's, another congressman was having trouble with his own form of Parkinson's," he often says. "You remember Paula Parkinson?" -- the blond lobbyist who kissed and told about her affairs with several congressmen. "I said at the time that there were many similarities between the two. They both cause you to lose sleep -- and they both give you the shakes." Mr. Nice Guy

The walk is a little slowed now and the tremors sometimes come as Udall, a lean Giacometti figure of a man, moves through the corridors of power, but the wit and grace remain undiminished. For 24 years Udall's humor and vision have helped guide his colleagues from paths of mediocrity. The Almanac of American Politics calls him "one of the leading and most productive Democratic politicians of his generation." He was a pioneer, on the cutting edge of such issues as the environment, campaign financing and civil service reform long before they were fashionable.

Sen. Gary Hart (D-Colo.), another Democratic presidential hopeful, says "history will count him as one of the great environmentalists." Republicans on the House Committee on Interior and Insular Affairs, which Udall chairs, may disagree with him on 10 out of 10 issues but practically genuflect when they speak of the man: Robert Lagomarsino of California calls him "the fairest chairman I've ever known." Dick Cheney of Wyoming praises his "wit and grace and fairness -- one of those handful of members held in high regard just because of his own personal qualities." And a 34-year-old freshman conservative Republican from Texas, Joe Barton, says, "my only concern with Chairman Udall is that agewise he's not going to be here as long as I hope to be here."

"It's impossible to dislike him," says Hart. "I don't know any Udall enemies."

Paradoxically, Udall suffered from the view that he just wasn't mean enough to be president. Some members of the press either wrote him off as Mr. Good Guy or, because they liked him so much, bent over backward to give him a harder time than they gave Carter. "Carter had 90 golden days that spring," recalls Udall. Once during a poker game on the Bazzler Bomber, a reporter turned to Udall and said he just wasn't presidential enough to make it: "Here are the reporters and Secret Service, sitting in the seats -- and there you are, sitting on the floor."

Some former aides feel that Udall's staff did not emphasize his nice-guy qualities enough. Said one, "We should have done a 30-second spot just on the Army and his eye."

When World War II broke out, Udall tried to enlist and was rejected. Then he was drafted for ROTC -- and passed the physical by placing his right hand over the bad eye, then placing his left hand over the same bad eye. He was eventually found out and bounced from ROTC but wangled a spot in a special service outfit composed of the partially handicapped. He was sent to the Pacific -- in August 1945. "I landed on Iwo Jima on D-Day plus 100, along with some athletic equipment and a piano."

After the war, Udall played pro basketball with the Denver Nuggets, an experience that became grist for endless jokes about being a one-eyed basketball player. Working the Hill

When Udall's older brother Stewart left Congress to become John F. Kennedy's secretary of the interior, Udall -- then an Arizona trial lawyer -- ran for his seat and soon joined his brother in Washington in those heady days of social change. A skinny young congressman, partial to turquoise belts and a scalped brush cut, Udall later succeeded in demolishing the House seniority system, a victory he still counts as major. He was floor whip for all the civil rights legislation of 1964, then became one of the first Democrats to break with Lyndon Johnson over Vietnam. And in 1969, when an ex-GI named Ron Ridenhour wrote 30 congressmen that "something rather dark and bloody" had happened at a place called My Lai, only Udall took action, starting an inquiry that flushed out the awful secret of a massacre of civilians in a Vietnamese hamlet.

Udall's style is to bring diametrically opposed politicians to a middldle-ground, and his hand prints are on many major bills -- from the Alaska lands legislation to toxic waste. Congressman Cheney once watched in admiration as Udall maneuvered. "I had a bill on a water project in Wyoming that I wanted. He took my bill and used it as a vehicle to add two items, a water project in Arizona he was interested in and a rewrite of all the reclamation statutes that the president wanted, and got all three passed by a voice vote."

Although a young Turk, Udall was no knee-jerk liberal. He called among the first to call for change in controversial big-project housing programs, spotted early the fiasco caused by handing over vast sums to some local agencies for job training programs and took some heat from liberal friends for saying that mandatory busing didn't always work.

Although many aspects of the sort of liberalism he championed are being questioned by a Democratic Party increasingly centrist, Udall escapes the old-hat image placed on such Democratic war horses as Thomas P. O'Neill, Edward Kennedy and Walter Mondale. Other congressmen say this is, in part, because of geography.

"He thinks as a westerner," says Cheney. "Nobody would call me an environmentalist but Mo and I see eye-to-eye on some legislation involving the land and water. We sponsored acid rain legislation together, coming from different perspectives, me as a conservative Republican and him as a liberal Democrat."

At 63, Udall has probably gone as far as he can in politics. Having failed in bids for majority leader and then for speaker of the House, Udall also lost a chance to run for Senate in 1976 because, ironically, his consistent second-place showing kept him in the presidential race too long. Udall occasionally ruminates over the "what ifs" of life, but seems to have little residual pain. He's the guy who believes that in a pile of manure, there has got to be a pony somewhere. "I got beat for speaker and majority leader but I think each of those races pushed the frontiers of reform out a little bit further. It all came together that day in early '75 when we dumped four committee chairmen totaling l50 years of seniority all in one afternoon." Parkinson's Disease

It was Parkinson's disease that kept him from running for president again in 1984. And, in order to dispel rumors, Udall had to announce early that he will run again for Congress next year. His mind grasps ideas and issues as keenly as ever, but the disease makes it difficult to perform the small tasks of daily living. His wife Ella buttons his buttons and knots his ties and blow-dries his hair in the morning. "He can do some of these things but it is a matter of 20 minutes versus an hour or more," she says. At times, Udall is in severe pain, though he makes light of it, and he exercises daily to keep his muscles from stiffening. Members of Congress who see him daily say he never complains.

"I don't feel lucky in having gotten the damn thing, but I feel lucky that in my case it is not as disabling as it is to a lot of people. I grew up in a home and a community where everything was optimistic. My father chief justice of the Arizona Supreme Court in the '50s preached values of independence, taking things as they come. If-you're-stuck-with-lemons-make-lemonade sort of philosophy. I think of my misfortune and then when I see people my age with Parkinson's who cannot walk or talk, I just feel fortunate."

Parkinson's, while not curable, is treatable, and Udall tells everyone, "I won't die from it, but I will die with it." The problem, he explains, is a shortage of a "substance produced in the brain that kind of lubricates the nerve paths when your brain sends a message to tell your hand to throw a baseball or button a button. With Parkinson's, the brain stops producing it, not all of a sudden, but 10 to 15 percent a year. The medicine slows that whole process down."

There were no signs of the illness one day recently when Udall took part in a long interview, but the next night at a public function, his head bobbed noticeably. "What you are seeing, when his head bobs, is simply a transient response to an overdose of medication," explains his doctor, Tom Chase. "He was being a nice person as usual and offered to participate in a study of an experimental drug. He has been marvelously supportive, offering himself up more than most in ongoing research to benefit all Parkinson's patients."

Udall has done TV ads aimed at getting the disease out of the closet, urging victims to attend meetings and others to send money for research. As honorary chairman of the American Parkinson's Disease Association, he speaks often to Parkinson's patients and finds himself touched by the many who tell him "you are a hero to us."

Udall revealed he had Parkinson's in 1980, hoping by 1983 that it would not be a detriment for a second run at the presidency in 1984. Staff members, his wife and close friends weighed the problem. They thought about handicaps. Someone brought up Franklin Delano Roosevelt, and someone else remarked, "Yeah, but they didn't have TV then." Ultimately, Udall says, "I could see myself at 400 small airports, wanting to discuss issues, and getting 'Congressman, tell us about this brain disease that you have.' I realized the election would be turned into a seminar on Parkinson's disease."

And so Udall went on to campaign for Mondale, for other members of Congress. Always a draw at fundraisers, he expects to help out others once again next year. Whither Liberalism?

While other Democrats bemoan the apparent passing of liberalism as an effective political movement, Udall believes "the high tide [of conservatism] was reached with Reagan's election. The pendulum swings and I think it's coming back.

"There's an ebb and flow, an ebb and flow. The first term I was here [1969] was probably the high-water mark of what became the religious right and all the rest. It was a tumultuous, horrifying time with 'Impeach Earl Warren' signs, and I wrote a piece called 'Fright for Sale.' The John Birch Society was very active, and at Arizona State I was catching hell, having to defend Eleanor Roosevelt against charges of communism from serious students asking such dumb questions. That peaked. I remember the whole McCarthy scene, and it went away.

"Prayer in school is already a dead issue, and if you took a secret ballot on abortion it would be a dead issue. A very intense group makes it rough for members in competitive districts but in 10 years that will also be a dead issue."

Liberalism, he believes, "may have a new day" but in somewhat different form. "The essence of liberalism is you make change. It is not static." For it to work, he says, three ingredients are needed: a basic commitment to social change, an agenda ("in the '60s it was civil rights and Medicare and aid to education"), and finally, a set of leaders who can inspire.

Udall, like most in his party, has no candidate for such Democratic leadership. "1988 is going to be like 1976, where there was no front-runner, no obvious heir apparent," says Udall. "My own governor Bruce Babbitt is running," Udall chuckles, "but Jimmy Carter has kind of poisoned the well for governors for the next 200 years."

When Udall announced that he would not seek the 1984 presidency, he said, "I want to help put an end to the Reagan administration, whose policies are wrecking this country." Yet Udall the optimist -- as well as the consummate liberal -- finds good things even in this administration.

"If you told me four years ago that my hopes and dreams for arms control rested on the shoulders of Ronald Reagan and John Tower, I would have said you're crazy. Yet Ronald Reagan and John Tower can go to the U.S. Senate and get a treaty confirmed. It's a heavy price to pay -- all this Reagan philosophy and social and environmental damage they have done -- but it is the up-side of that administration.

"I just can't understand it," he says, shaking his head. "The most conservative president in my lifetime gets away with doubling the national debt." Udall insists a day of reckoning is not far off. You can see the campaign one-liner forming: "It took us 39 presidents, six wars and 200 years to rack up a billion dollars and this guy doubles it in four or five years!" Leave 'Em Laughing

This spring, Holt, Rinehart and Winston is scheduled to publish a collection of Udall's sayings, jokes and remarks. His computer contains more than 1,200 of them. "I steal," says Udall, "from everyone from Lincoln to Reagan."

Besides the apocryphal, the book includes stories and jokes that Udall swears are true, one of which provided the working title, "Just Laughing About It This Morning." In the early days of the '76 campaign, Udall was sliding from one snowbank to another, in the time-honored ritual of wooing New Hampshire voters. He walked into a barbershop and said, "Hi, I'm Mo Udall. I have just announced that I am running for president."

The barber paused slightly in his clipping, and said, "Yep. We were just laughing about it this morning."