LIFELONG friends have called and said, please, please, don't do this, you're going to end up hurt and looking like a damn fool idiot. Just the other day there came a postcard with a picture of the Corn Palace in Mitchell, S.D., on it. He turned it over and recognized immediately the signature of a woman who used to raise money for McGovern campaigns. Once, she dreamed all his dreams. There was no "Hi George" on it, no "How are you?" just two words:

"FORGET IT!"

His hand scrawls the words on an imaginary postcard in the morning air. He is sitting in a glass box on Connecticut Avenue, far from the Corn Palace. It is a small office, and in a larger outer one people less than half his age are working the phones, grinding out releases. But there are some old believers here, too.

"That's okay," George McGovern, candidate for president, says with that odd, pained grin that spreads his lips thin and tight against his gums. "I know what she was trying to tell me. I still love her dearly."

There is something haunting, maybe even poetic, about the Washington man who won't go home again. One of the myths of American politics is that our leaders rise up from Independence or Abilene, strut their hour here, and then, when that is over, return to their kinsmen, who have fueled their greatness all the while in an almost mystical way. The idea is that they are only here in trust.

The myth is as dry as husks in an October field. It cracks open at bare touch. Few go home, and fewer have ever wanted to. Yes, Sam Ervin did, and, yes, Jimmy Carter did, and, yes, Captain Harry got the hell out almost as soon as he could get the car loaded. (Actually, he took the train to Missouri.) An aide walked in on him that morning. "Two hours ago," Truman said, "I could have said five words and been quoted in 15 minutes in every capital of the world. Now I could talk for two hours and nobody would give a damn."

The need for fame, the TV camera's old glare, is not what is making George McGovern run for president again, 11 years down the road from the last disastrous time, he insists. He has made quite a handy living from riding the lecture circuit, not to speak of some canny Washington-area real estate investments.

No, it's the issues, it's the country, it's his conscience. As soon as his family understood that, they said okay. It took a month of convincing them this summer at a retreat in the Smokies. The kids, grown now, came down in "installments" he says. Two of them said right off: Let's go, Dad. The other three asked him not to do it.

"I decided that we needed a month. I couldn't say, 'I'm going to run and the hell with what you think.' I had to have a month, to talk it out with each of them. And I think I got all of them to accept it graciously. Maybe it wasn't the thing they wanted me to do, but at least they could see it was the thing I had to do--to be a public man again, to weigh in on the public issues."

There are five McGovern children--four daughters and a son. "I think they all saw the logic of it," the father says slowly, "but I don't think they could see my willingness to take the . . . risk." This last word is said lightly, like something you slide in a drawer without studying very much.

One of his daughters, Mary McGovern, is sitting in the next room. She is 28, the last child, a fighter, fiercely proud. She has quit her job at the United Nations to join the campaign. The last time her father ran for president, Mary McGovern was in 11th grade at Bethesda-Chevy Chase High School. It changed her whole life, and not all of it was good. "It was impossible to be just another kid," she says in a sentence that tells you oceans more than it says. Right now Mary McGovern's job is trying to find bigger offices.

Three years ago, after George McGovern lost his Senate seat, Mary wrote a heated letter to the editor of The New York Times, defending her father against the right-wingers she felt had driven him from public life, closing with this: "But I assure you, you have not heard the last of George McGovern." Her dad didn't know she had done it until after she had sent the letter. "No, I don't have any special ties to his unconscious," she says.

Today, after her dad has talked for 90 minutes, she comes and takes a seat opposite him and says this:

"I'm surprised at how little of it does hurt me, the attacks on him, the abuse. The way I look at it, when people write stupid things about my father, untrue things, they're the ones who have to live with it. His profession is public life. His profession is politics. I had some basic questions for him this summer, personal stuff about the family, and once he answered them, I said, 'Fine.' "

"You get so caught up in it," McGovern says. He is speaking of last time. "All that has changed. I'm going to go into every state. I'll be in Iowa and New Hampshire. But I made a commitment to my family this time. I won't drop out of life. I'm very sensitive to knowing some of the damage it did in my family before." He doesn't elaborate on this, and when you nudge him to, he declines. Mary won't budge on it, either. "It's private," she says.

He is 61. He seems fit and calm. (There is a slight overhang of stomach, but you wouldn't notice with the jacket buttoned.) The old politeness and midwestern earnestness are still there. The voice is full of those same flat, guileless--almost gritty--middle-border cadences, never mind that he's been a Washington man for 27 years. It is a voice that can both reassure and oddly grate in its accents. His dress today seems a bit like that, too: blue slacks and a big, bright, checkered sports coat. This could be a judge at the weekly Rotary in Sioux Falls.

The cynical would say (and have) that George McGovern is back in because he can't live without it. Think of Muhammad Ali, who left one ring but couldn't get out of another: glory, and the need to have it. When you can't cause drama in the Bahamas, you play shopping centers in Virginia Beach. Diminished expectations, diminished returns.

Some Washington hands have even speculated, albeit privately, that the real reason McGovern is in is not because he figures he has any chance of getting the nomination, but because it will enhance his business and political connections. He is already on record with his frustration at not being able to get on network TV these past few years.

If you page through McGovern's 1977 autobiography, "Grassroots," you find affecting passages such as these: "The day after a losing election, the candidate reverts to the shock of 'normal' living. The Secret Service, the campaign staff, the crowds, the press--all of these disappear overnight. Suddenly an overwhelming loneliness replaces the excitement of the cheering crowds . . . The ideas as well as the individual have been defeated."

"Here," George McGovern says, grinning, giving you a free copy of the book. "They're not selling too well."

"We give them away with the coffee," says Mary McGovern.

"Look, I'm not trying to vindicate my place in history, or get even for my '72 defeat, or inflate my ego," says the man who looks eerily like the 50-year-old candidate who managed to capture the country in one season of 1972 and lose it hysterically to Richard Nixon in the next--in the biggest political landslide in modern American history. He almost seems not to have aged. "And in fact this could turn out to be quite a big ego deflator. Because I sure as hell don't know how this thing is going to come out. But I have to try. We are in such sad shape."

The country, he means. "Since childhood I have been a student of history. His doctorate in American history is from Northwestern. If Ronald Reagan knew anything about the history of our involvement in Central America, he would never have his covert operations trying to overturn that government in Nicaragua. Same thing with El Salvador. I don't say the insurgents are Sunday school boys."

Another McGovern daughter, Ann, is coming over to the campaign Monday. She is the eldest McGovern child and has two sons of her own. She has been working for the Navy Family Service Center. "My reluctance was more a daughter's concern for her father," Ann says, when you call her up and ask her about her father. "I started talking to him about it as long ago as last Christmas. Finally I could see that not running might be more harmful to his psyche than running and getting beat. Alongside of that, my reluctance began to seem petty. And anyway, most of my dad's campaigns have started from far back."

Eleanor McGovern comes in. She, like her husband, is 61. She is a small woman, gracious, dressed in muted reds. She sticks out her hand and smiles wanly, warily. There is a weight about her that seems at odds with her delicate features, giving her the tenderness of, say, a Cassatt painting. She is leaving town in the morning to drive to South Dakota. A niece is getting married there in a week or so hence, and Eleanor will stop off in Wisconsin to see some of her children and grandchildren. She is leaving at dawn, and suddenly seems to brighten at that fact. "My husband is going to join me out there," she says.

"Yes," he says, "I'll get there Saturday for the wedding at 4 o'clock and then afterward charter a plane to Chicago. It's the only way I can figure out to get back to Washington in time to give a speech on Sunday." This is 1983, but if you're in Mitchell, S.D., on a Saturday night and need to get to Chicago, the only way to get there is to drive all night or hire your own plane. The latter isn't cheap, even for a well-off man. "I made a commitment to Eleanor to go," he says. "Now if my niece gets divorced in a year . . ."

People who know Eleanor McGovern personally say the defeats of '72 and especially '80, when her husband lost his Senate seat after 18 years, have taken their heaviest toll on her. Eleanor has publicly said she will not participate this time around. Her husband doesn't think she will hold to that.

"Yes, it's true," he says after she is gone, "she's been hurt the most in the family. Me, I just figure the criticism of your character or whatever are part of the price. Not that I don't get outraged sometimes, mind you. It's the misconception of what you say, the twisting of your ideas, that you really hate. You take that 'fuzzy-headed liberal' rap. Well, I don't think it's true. I think I'm incisive. Let people hear me out, hear my ideas, and if I sound like a fuzzy-headed dreamer, don't listen to me, don't vote for me. Sure, I get mad when they do that, but then I forget it. But somehow to this day Eleanor just cannot adjust to it. I've tried to find out why she reacts so sensitively to criticism of me. I think it's because she sees it as some kind of public stripping away of my life, my soul."

An anger flashes, against the old, wry, midwestern self. "I think that 'fuzzy' label, by the way, goes back to the Nixon television commericals in '72. They just saturated TV with a picture of my head spinning. And why? Well, for one thing, because I said I was for Senator Eagleton as my running mate 1,000 percent, and then a week later changed my mind. I'll never understand what was wrong with changing my mind on a complicated issue. Hell, I didn't know anything about mental illness. I didn't know he had a history of that. The more I talked to psychiatrists, the more I thought he should step down."

He is playing with the ridges in the leather of a maroon sofa. His legs are crossed, and a coffee cup with a bird on it is in his free hand. Over on a table is a framed photograph of Atticus, a great black Newfoundland who was put to sleep more than a year ago at ago 13. Atticus was Mary's dog and was named after Atticus Finch from the novel "To Kill a Mockingbird."

Above his head is a painting of Taos, N.M., a place he and his wife are in love with, Eleanor more than he. If Eleanor had her way, they'd go to Taos tomorrow for good, Washington and their cushy life here be damned. On the other wall is a portrait of FDR, a Washington man who had the mystique and great good luck to die out of town.

"Eleanor came in here to get some packing boxes for her trip, that's all. But I think she's going to get involved in this, I really do. I took her out to dinner at Duke Zeibert's last night. She started asking me questions about the campaign and I sort of brushed them off. It was clear to me she was hurt. You know how it is, after you've fought battles here all day, you don't want to go home and have to defend your thinking again. But I just sort of brushed her questions off. And I could see she really wanted to know."

Several months ago, McGovern met off the record with some veteran Washington political writers. He asked them candidly about his chances. The news was not good. "They said, 'The reason you are perceived as a big loser is that you lost the presidency, you lost your Senate seat in '80, and furthermore you are coming into this thing late. You'll have to be prepared for all kinds of things, like, 'Isn't it terrible what he's doing to his old campaign manager, Gary Hart?' Well, I have to admit, these are sobering thoughts. I've come awake in the middle of the night and said to myself, 'What the hell are you doing, George?'

"I haven't done that in a while, though."

One May Sunday a year and a half ago, Eleanor and George McGovern got into a car and headed out of Washington. They drove south, bent on a month-long tour of the country, with a special emphasis on the national parks. Eleanor was happier than she had been in years, her husband says.

"What happened, you see, was that after I was defeated in the Senate race, we felt a kind of emancipation. Neither of us shed many tears over that one. Oh, sure I wanted to win, and there was the fact of a rejection by your home state and all. But in another way I was greatly relieved to be out of the Senate. Eleanor and I felt we had lost touch with our country."

They began in the Shenandoahs and cut down into the Smokies, turned west across Tennessee, and kept driving. They saw the Tetons and they saw the Sangre de Cristo, but looking back, one of the areas they remembered best was the Great Smokies. So last spring they went back and ended up buying a little cabin near Shagbark, Tenn. "The Smokies were my compromise to Eleanor," he says. "I'm not ruling out New Mexico. It's just so damn far."

For an instant he seems dreamy, far away. "She's an identical twin, you know. I used to debate them when I was in high school. I had no particular interest except to beat them. We ended up at a little Dakota college and started dating at the end of our freshman year. We've been together ever since. I guess the thing that's kept our marriage alive--and God knows that is never easy--is that neither of us has stipulated what the other can or cannot do."

He was listening to a radio broadcast of the New York Philharmonic on Dec. 7, 1941, when an announcer broke in and said Pearl Harbor had just been attacked. The minister's son interrupted his studies at Dakota Wesleyan and enlisted immediately; the Army Air Corps didn't call him up for another year and a half.

George married Eleanor on Halloween, 1943. He was on a three-day pass from an air base in Muskogee, Okla. On his wedding weekend, Air Cadet McGovern spent all Saturday getting home, Sunday getting married, Monday getting back to the base. The newlyweds got into Muskogee at 2 o'clock in the morning. They had sat up all night in the coach car of a train on wicker-back seats, with choking air and babies crying all around them and soldiers flirting with any Jane in a skirt. There was something surreal, charged, about it. On the platform in Kansas City, someone stole their suitcase. The suitcase held most of their money, all their clothes.

"Hell, we were just youngsters, both 21. I looked at Eleanor and she started to cry and I did, too. Our whole relationship, all our early time together, is dominated by that war. It was the centerpiece of our lives. But we really didn't consider it a hardship. Everybody was so caught up."

Later he circles back and says, "Bombers, I flew bombers. You know, it must have been something about the bombing of Pearl Harbor that made me want to go bombers."

Last Saturday, at a little after 4 p.m., a candidate for president of the United States pulled up alone to the International Hotel at Thomas Circle in a yellow cab. He was the last candidate of the day to address the national board meeting of the Americans for Democratic Action. He had just come from the Congressional Black Caucus across town, where he was said to have done very well. Nevertheless, he could have read in the morning paper Rep. Charles Rangel's unkind remark that "No one should be critical of Jesse Jackson with McGovern in the race. McGovern is the joke."

"He's here, he's walking in the door now," said a man into a walkie-talkie. Cameras whirred and clicked. There was a mild crush. George McGovern made his way through, shaking a hand, kissing an old face he remembered from other wars.

At the podium he outlined the eight things he would do as president, beginning immediately, he said, with getting America out of Central America and Lebanon. He said he would put the country back to work again--on roads, the soil, the railroads. "I'm an unabashed New Deal Democrat," he said. He was low-keyed, assured, modest. He wore a gray suit and black glasses and talked with his hand in his pocket.

He spoke for about 40 minutes, answered questions smoothly, then said, "There's a little plane out here waiting to take me to Tennessee. I have to talk at a dinner there this evening."

Outside, a staffer had a car running. She scooted over, the candidate got into the driver's seat. A nondescript maroon sedan slid out into the pumpkin-yellow sunlight of 14th Street, past hookers and hustlers and other earthbound schemers. George McGovern, the once and would-be nominee, was taking himself to an airport and bigger dreams.