Isabel Peron had the idea first. When the military junta was about to overthrow her Peronista regime in 1976, she suggested Alejandro Orfila as a transitional president of Argentina. It didn't happen, but now talk of Orfila for president is flowing once again.

Indeed, Orfila has come far since his days as Juan Peron's ambassador to the United States nearly a decade ago. Back then, he wrestled his way into the Washington limelight by entertaining in the showy ways this city had rarely seen since the days of Perle Mesta. As a wealthy, gregarious bachelor, he became known for the many beautiful women he dated as well as for the powerful guests who frequently filed into the Argentine Embassy for his parties. His social peak perhaps came one snowy January night six years ago when he escorted Jackie Onassis to the Kennedy Center, entertained President Ford and Betty Ford before network cameras and met his wife-to-be--all before midnight.

In 1975, after two years on the social pages, Orfila parlayed this visibility into a successful campaign for his current job: Secretary General of the Organization of American States.

Now, with yesterday's cease-fire and Argentina's apparently imminent surrender in the Falklands, the country's political order could crumble. And the possibility has been raised that Orfila could be summoned home by the leading political factions to pull the country together, acting as either transitional president or foreign minister. During his most recent trip there last March before the Falklands' invasion, the subject was broached to him by five leaders of the major Argentine parties at a private dinner in Buenos Aires.

It is a scenario that would allow Orfila to one-up Argentina's most famous president, Juan Peron. Peron was called out of a 17-year exile to return as president of Argentina. Orfila, by his own choice, has not lived in Argentina for more than 30 years. Some say he has been priming for the job for decades. But other observers say it is Orfila's pipe dream; that the man most known in Washington for throwing flashy parties is at best a wheeler-dealer public-relations specialist.

From his vast Washington office at the OAS building, Orfila states and restates that he is not seeking the presidency of his homeland. But whether he would accept it, should it be handed to him--that's another story. Orfila seems to be simply sitting back, waiting for the speculation to carry him forward.

"I am not a loser and you know why I am not a loser," he says in his quick, choppy Spanish accent. "I don't tackle things I cannot handle. You know this now-famous bidding by me for the job of secretary general of the United Nations? . . . I never really moved a finger on my own--really--to promote that possibility . . . I let the possibility promote by itself. I let it go by, never denying it yet somehow promoting it . . . But I never went after it because I got the feeling that I was going to have an uphill fight and chance of losing. And I don't like to lose."

Orfila is candid about the fact that he never wants to be in the position where he goes after some- thing . . .

". . . and fail?" Orfila is on his feet now, fingering the hand-tailored, pin-striped suit, pacing behind the huge mahogany desk. "I haven't done it up until now and I'm 57."

And if he doesn't actively pursue the job of president of Argentina? If they come to him, then is he protected against failure?

"Exactly!" he says. "The moment I seek that job I am doomed. I am ruined . . .

"Oh yes, I protect myself. I don't make an unnecessary move ever . . ." Questioned Motives

It is stories such as the one about events in La Paz, Bolivia, that make some people suspicious of Orfila.

In October 1979, the foreign ministers of most Latin American countries and several hundred OAS staffers were in La Paz for the annual OAS general assembly meeting. During the week, a Bolivian general called a press conference to announce that he was about to overthrow the government. Understandably, an announcement of a coup was not taken too seriously. And since coups are not exactly rare in Bolivia--the country had five presidents in one 24-hour period in 1971--the general's warning was virtually ignored.

The OAS meeting adjourned late in the evening of Oct. 31, and the surprise came in the early morning hours of Nov. 1. Gen. Natusch Bush did in fact overthrow the government.

By 9 that morning, Orfila had been escorted to the airport by Bush's people and was safely on his way to Argentina.

"There were tanks all over the street, and Orfila left the entire OAS staff there to find their own way out of the country and only took his sidekick William McGough with him," says Wilson Belluso, a 20-year OAS veteran staffer who is now a free-lance writer on Latin American affairs. "He knew about the coup and didn't warn anyone."

"We found out about it that morning at 6, and we had already planned to leave for Argentina," says McGough, the Argentine press officer for the OAS who has been friends with Orfila since 1957. "The new government offered him an escort to the airport as a courtesy."

"I don't think he knew about the coup," says an adviser to Orfila who asked for anonymity, "but I told him he should have gone right back when he realized all his people were stranded there."

Orfila denies he left everyone stranded. He says that, unknown to everyone, including McGough, he arranged for the safe departure of his entire staff before he left for Argentina.

"Who was killed? Who was wounded? Who was harassed? Who?" he asks. "Everything was perfect. Nothing happened."

Till this day, some people involved are convinced Orfila arranged only for his own safety.

"The people who believe in things like that are mediocres," he says. The Flamboyant Ambassador

Orfila, as secretary general of the Organization of American States, is caretaker of an organization that most foreign affairs experts describe as "moribund." The OAS had no input into resolving the situation in the Falklands. Like the OAS, Orfila has observed from the sidelines the war that has imperiled his nation because he says he has "31 bosses," the OAS member countries, and must remain neutral.

His is a position long on title but short on power, but it is a job Orfila went after with a passion in 1976, and which he won by one vote on the third ballot. His tenacity in pursuing it while he served as Argentine ambassador to the United States led to early conjecture that he was simply in search of a base from which to further promote himself.

"He is the quintessence of public relations in government," says Henry Raymont, a writer who has lived in Argentina and who once worked for Orfila at the OAS.

A career diplomat who once served as Argentina's ambassador to Japan, Orfila has thrown parties for everyone from the U.S. governors to Secretary of State Alexander Haig, serving only the finest wines with his own label, from the Orfila family vineyard in Argentina. As Argentine ambassador to the United States, he often supplemented the embassy's entertainment budget with his own money.

Yet, when he first took over as secretary general of the OAS, Orfila's flamboyance was not appreciated by the other ambassadors. He was criticized for being too social, too rich, too American. Besides the family winery, Orfila has substantial real estate holdings here and abroad and a separate office on Connecticut Avenue with a manager to handle his investments. On weekends he and his German-born wife Helga visit their Middleburg, Va., estate to ride on the 200 acres. They own 12 horses. They also have a large home in Jamaica and still maintain the East Side Manhattan apartment in which Helga lived before they were married. He is reluctant to talk of his wealth, simply referring to himself as "well-off."

"I had to change my style, be careful not to stick my neck out too far," he says of his early days at OAS. "It was criticism people have for a fellow who is well-dressed when you are not well-dressed, a guy who is wealthy when you are not wealthy. They didn't like the parties given by me, but they liked the parties. They would have been beautiful if they had been given by them . . . In the early days, everything I did was wrong . . ."

By 1977, he was giving fewer parties, but maintained his knack for staying in the news. At the formal signing of the Panama Canal treaties that year, the world watched as his new bride Helga arrived wearing a white silk brocade gown with a neckline that plunged to within a few inches of her waistline. Later, Helga Orfila dismissed all the gossip about her "navel dress" by telling the press she didn't understand what all the fuss was about anyway because she was "flat-chested."

". . . All you have to do is look at Helga and see she has nothing to see," Orfila said at the time.

Orfila, who with his hefty build and thinning hairline looks more like anybody's father than a slick operator, seems unconcerned that he might be perceived as a self-promoter or frivolous. He dismisses his detractors as jealous. "I have made one cardinal sin: being successful," he says flatly.

"I took a chance that I would be perceived as frivolous, as a playboy, and be called a lightweight," he says, "but the people who know me know I am not frivolous. And all the other people I don't care about . . ."

There is something quite likeable about Orfila. He always appears personally concerned with whomever he is speaking. And his candor comes across not at all boastful, but charmingly honest--like this is the way everyone operates in Washington.

"I believe that visibility in our profession is important . . . it's not an end, it's a means. Why? Because visibility and moving and being known allows you to know people that eventually could be extremely important to you in a very serious professional way."

Scattered throughout his office are rows of colorful reminders of his success--photos of him with Ford, Carter, Reagan, Kissinger, Rockefeller, Haig. Latin American embassies never have had the diplomatic panache or clout afforded to the great powers like Great Britain or France. But within a short period of time, Orfila dominated the social pages, his only competition at the time having come from his good friend, then-Iranian Ambassador Ardeshir Zahedi.

"He and Zahedi--they both had the movers and shakers moving in and out of their embassies," says Robert Keith Gray, Reagan insider and president of the Gray & Co. public relations firm. "He's been a consistent friend and an ultimate diplomat."

"I could never do what he does," Helga Orfila says of her husband. "You have to have patience. He never sees a bad thing in anybody. I do . . . He can go, go, go 24 hours a day; and if he's not, he's an unhappy person. We're completely different . . . I don't need to do that . . . I can paint. I can work in the garden and not see anyone. I'm not bored with myself . . ."

Latins in Washington generally are less than generous. To many of them--even he concedes--Orfila is a hustler and opportunist who believes only in Orfila. They see him as a man who has managed to manipulate the best of both worlds: prominence in the United States and clout in Argentina. And many say they do not see him as the next president of Argentina.

"He has lost that light sadness, that melancholic outlook which is the stuff Argentines are made of," says Argentine journalist Ary Moleon, a longtime critic of Orfila. "He is no longer an Argentine. He does not have the natural reaction of an Argentine. He is an American." Romance and Marriage

Orfila first spotted Helga Leifeld at the same Kennedy Center gala to which he escorted Jackie Onassis. He excused himself from Onassis for a few minutes and went looking for her, a New York model with a striking presence. She is tall and lanky, and usually wears her waist-length blond hair severely pulled back from her face, accentuating her high cheekbones. They were married within a year, the second marriage for both.

"It was her look, her smile, her walk," he has said. "They were all right."

"She's a lovely hostess and housemate for him," says their good friend Betty Lou Ourisman. "They complement each other very well."

But their romance raised a few eyebrows in the early days. Helga Orfila didn't like Washington at first and maintained her apartment in New York, returning there often. Before and after their marriage, she has traveled in celebrated circles and has been featured often in W, the slick society and fashion tabloid. Her friends include Frank Sinatra, producer Sam Spiegel and fashion designer Zoran. She dated Sinatra in Los Angeles during the early '70s, after she arrived from Munich.

"He wanted to meet me," she says. "I said it must be a mistake, I don't know him . . . I was in a nightclub someplace with a group of people. I was simply dressed. I was a new face in town."

Her former life, as well as frequent absences from Washington, set the gossip mill turning with rumors of troubles that both of them say they find funny. "I never knew I was so important," she says. "In Germany, we have a saying: If they talk about you, you're okay."

She still has the apartment in New York, which she says she visits every two months. She also goes to their home in Jamaica four times each year--usually without her husband, who says he finds Jamaica boring. And she has kept all her platonic friendships with men, which she says her husband is getting used to.

"I think he's getting better with it," she says. "Still, it is not the same as European men would take it. He doesn't understand, for instance, if say I had an affair 15 years ago with somebody--I didn't get married at 17, he had his life and I had my life--he cannot believe that you can turn out to be buddies or friends."

Asked if she minds seeing his old girlfriends at parties, she says, "I couldn't care less."

Orfila describes his wife, who is 38, as an unassuming person and an intellectually honest person--too honest at times.

"She's extremely frank, sometimes a little too frank for my business," he says. "If it doesn't upset me, sometimes I feel a little uneasy. I would prefer she didn't come across so loud and clear."

And so during a recent interview over coffee at their luxurious Northwest house, Bill McGough sat with her and a reporter. "I asked him to come because I don't want to talk political," she said.

Being first lady of Argentina, she said, is not her cup of tea. She doesn't even like to think of the idea of settling there. "If it happens that we have to go back, then I will make up my mind," she said. Last year, however, in an interview with Woman's Wear Daily, she said that "Evita Peron was an asset to her husband. He used that. Why not?" The International Link

Orfila doesn't believe in theory. He believes in action and in communicating, he says. Once in 1963, when he was a private lobbyist, the Argentine sugar lobby asked him to negotiate a way for it to get a piece of sugar exports to the United States. He got it to send scores of Argentine professional athletes to Washington--golfers, tennis players, soccer players--to play with congressmen and federal agency officials. Orfila doesn't play any of those sports himself, so he just watched and threw after-game parties. The Argentines got their piece of the export trade.

He is also credited with bringing together the presidents of El Salvador and Honduras at the OAS, thereby starting the wheels moving toward a resolution of the 15-year border dispute between the two nations.

"He's a charismatic person, and he's always had a way of bringing people together," says McGough.

In 1974, Abraham Lowenthal, director of the Latin American program at the prestigious Wilson Center, conducted a research project to determine to what extent Latin American ambassadors understood U.S. policy making.

"One of the best who had a fully articulated and serious grasp of the process was the Argentine ambassador, Alejandro Orfila," says Lowenthal. "He is a very political man. He knows what the politics are, and he knows how to succeed--at least in this country he does."

"He is certainly a valuable link between South America and the U.S.," says Sen. Paul Laxalt (R-Nev.). "He has a real appreciation of problems that separate us, and because of his visibility in the U.S., he has high credibility in town."

It is precisely this understanding of the international arena which Orfila believes could be the greatest help to his country.

"My skills up until now have been to help Argentina abroad, and I could be very useful to Argentina because no country can isolate itself--none," he says. "I could be very useful in the case of international relations, international contacts, international experience . . . yes . . ."

Although Orfila walks the middle line politically and rarely states his position, he did muster considerable liberal support for himself in 1979--both at home and here--by vocally supporting OAS's Inter-American Commission on Human Rights. But he still hedges on the question of human rights in Argentina, a country that fared badly in the commission's study.

"It is true a lot of things happened, but a lot of things have been greatly exaggerated and over-dramatized," he says. "I don't want you by any means to believe that I'm trying to minimize the things or justify things that happened. But sometimes things of that kind must be recognized in context, in the habitat . . . Here in Washington we put a lot of emphasis on what happened to X or Y who disappeared, but we never put any emphasis on the daughter of the commander in chief of the navy who was blown up in her bed . . . or the poor soldier who was standing on a corner and was gunned down just because he wore a uniform . . . What about the human rights of this guy?"

Which brings back the question of whether Orfila, an Americanized Argentine, could really go home again.

"It is a question I ask myself many times," he says wistfully. "But if someone comes and says 'Do you want to be the leader of your own country' and you say 'No, I don't like it,' well, something is wrong with you!"

"I am very much an Argentine. I want you to know that because I have always felt that a person should know where he comes from, where his roots are. He should have an identity," Orfila says, slowly and emphatically. "And my identity is to be an Argentine. That gives me strength--I know where I come from, I know what I am and I know where I am going home one day. And one day may mean simply to be buried."