Ambassadors are said to lead enviable lives, but consider Juan B. Sosa: For the past four months he has been the ambassador of Panama to the United States.

He arrived Oct. 17, in the midst of a full-blown crisis in relations, and it's been downhill ever since. Eleven days ago two federal grand juries indicted Gen. Manuel Antonio Noriega, the de facto head of Panama's military-controlled government, on charges of racketeering, drug trafficking and money laundering.

Last week, headlines were dominated by the Senate testimony of former Noriega associates who wove a galvanizing tale of double-dealing. On Friday, the second-ranking Panamanian envoy to the Organization of American States, Lawrence Chewning Fa'brega, resigned to protest a government he said was "characterized by corruption, illegitimacy and dishonesty." Sosa himself was briefly recalled to Panama for consultation. The American press, which routinely describes Noriega as a strongman, is now reporting allegations that he is a torturer, a gunrunner, an extortionist and -- this from Newsweek -- a bisexual.

"My job right now is not an easy one," Sosa sighs, "and all that is going on makes it more difficult."

He is a neatly groomed man in gold-rimmed glasses and diplo-gray suit, affable, with all the time in the world to fight what he perceives as a war for world opinion. With him on his luxurious battlefield -- the living room of the ambassador's residence in Woodley Park -- are his British-born wife Margaret, 35, and children Enrique and Elisa, 8-year-old fraternal twins, all dressed to kill.

On Juan Sosa's third finger, left hand -- just above his wedding band -- is a massive black and gold college ring from the University of Oklahoma, 1963.

"We've always been very pro-American," says Margaret Sosa. "Always."

For this reason and others, Sosa can be seen as an apt embodiment of the weird contradictions that since last summer have dominated U.S.-Panama relations. Here he is, an ardently pro-American conservative whose early politics were formed in part by Barry Goldwater's 1964 presidential candidacy (Goldwater "was probably 20 years before his time," Sosa says), forced to spend his days defending an authoritarian Central American regime from the suddenly activist dismay of the Reagan administration. Here he is, the appointee not of Noriega but of the country's civilian figurehead president, cast as the defender of a military strongman whose very power over Panama he denies.

Sosa, 46, is not by training a diplomat (unlike Fa'brega, the former OAS envoy who spent more than 20 years in the diplomatic service). He has held marketing jobs with such multinational giants as Colgate-Palmolive and Philip Morris; more recently he has run his own business as a marketing and polling consultant, telling businesses such as Procter & Gamble, Kraft and Coca-Cola how to sell their wares in Central America. Since 1985 he has been the unpaid chairman of the board of Air Panama, by presidential appointment. But the accomplishment of which he seems most proud is his one-year term as the first Panamanian president of the U.S. Chamber of Commerce chapter in Panama.

He is also, Margaret Sosa chimes in, a Rotarian.

Sosa's main message is that "Panama has gotten very adverse publicity, most of it very unfair. ... I'm appalled to see what has become a circuslike atmosphere in the whole thing. Press. People testifying with hoods, or with federal agents surrounding them."

Margaret Sosa adds, "We do feel the focus has been {too much} on Noriega. And nobody has made an effort to mention our president, Eric Arturo Delvalle. It's almost as if he doesn't exist."

Which is more or less what the Panamanian opposition says.

Ask Sosa what role Noriega plays in the affairs of Panama and he says mildly, "In Panama, traditionally, the national defense forces have had a large role in the life of the country. That's fairly usual in Latin American countries. In 1978, the military made a commitment to go back to the barracks. We have seen since then that their influence is declining." To be sure, "There are some people who feel that the decline is not large enough or fast enough.

"But I can understand that," he continues. "The United States had a civil war 120 years ago, and it took Martin Luther King a hundred years later to really impose -- or effect -- some changes that were supposed to be -- I mean, that's why the Civil War was fought." He talks about evolution in preference to revolution. He talks about all the Reagan administration hot buttons -- "the negative effects we have seen in countries like Iran, in countries like Cuba, in countries like Nicaragua.

"Drastic changes," he says, "carry a very high price tag."

Relations between the United States and Panama have been rocky since at least June 6, when Noriega's former deputy touched off widespread popular protests by admitting that the Panamanian Defense Forces had stolen the 1984 election -- the nation's first in 16 years -- and charging that Noriega had ordered the 1985 decapitation murder of opposition leader Hugo Spadafora. The Reagan administration began to move away from Noriega, whom it had long supported and found useful, calling for him to divest himself of power.

Noriega has been working hard ever since to portray U.S. criticisms of him as Yankee imperialism and a veiled attempt to rationalize abrogation of the Panama Canal Treaty before the turn of the century, when control of the canal is scheduled to pass over to Panama.

Sosa agrees, more delicately, that "Noriega is in a way a symbol, but the actions are against Panama ... The U.S. role in this crisis has been a fairly large role. The action here -- hearings, statements, and so on -- projects the image that the administration is supporting the opposition." His best hope as ambassador, he says, is "to persuade {the U.S.} that the only way for Panama to go back to growth ... is for an agreement to be made between the national defense forces and the opposition forces, without interference of a third party."

The only sitting foreign leader who was ever indicted by the United States before this, according to the Justice Department, was a chief minister of the Turks and Caicos Islands, a tiny British protectorate in the West Indies. Most observers have therefore declined to predict an improvement in U.S.-Panamanian relations in the months ahead.

It is now unclear what Juan B. Sosa signed up for when he moved his family to this gracious house in Washington, with a commitment to serve until at least the scheduled end of President Delvalle's term in May 1989. He may be just another ambassador, with all the privileges of rank: going to the White House, where President Reagan was charming to his children; being interviewed on television; getting to know some of the American business leaders he admires.

And he may preside over -- or simply be forced to watch -- the bitter end of good relations between the two countries he most admires.

"Sometimes," he says, "I do get frustrated. As a businessman, I've been more used to action; the diplomatic life is much more frustrating."