The brothers Kalb:

One brother saw it from the rice paddies. The other saw it from the long gray corridors of the State Department. Now each has taken his side of the story -- the war of the paddies and the treachery of diplomacy -- and put them together. The result is a book which helps to explain why Vietnam still haunts those who were there.

The brothers, television correspondents Bernard and Marvin Kalb, make no apologies for writing another book about Vietnam. They feel that Americans have yet to stare into the mirror and think through all the implications of the war.

The book, "The Last Ambassador" (Boston: Little, Brown. $13.50) is a novel, not a work of fact. It comes close enough to the truth, however, to have forced this writer to live through the traumatic 1975 evacuation of Saigon a second time.

Once again I can hear the North Vietnamese artillery hitting the Tan Son Nhut air base, feel the panic sweeping the city, and see the crowds closing in on the US Embassy:

"They will shoot us all if you leave us here!"

That was the cry which this writer heard from an elderly, bespectacled Vietnamese at the embassy gate that last day in Saigon. The man shouted that all of his sons had worked for the Americans. He did get out.

Such was the panic.

The Kalbs bring it back.

In 1970, Bernard Kalb came home to the United States after long assignments in Asia with the New York Times and CBS News. But he found Vietnam "impossible to shake." He returned there on assignments for CBS through the early 1970s.

Marvin Kalb watched the war from the State Department. He remembers a Friday afternoon session in the late 1960s with then Secretary of State Dean Rusk. Rusk leaned over and put his thumb on the coffee table.

"When the US applies pressure to something, it gives," he said, pressing down with his thumb.

"But when we applied the pressure with 500,000 Americans troops and sent the B-52 bombers to Vietnam, it did not give," Marvin Kalb recalls. "We gave."

In many ways, their book is a product of an argument between the two brothers which began during the war.

Marvin explains:

"Because of his experience in Vietnam, Bernie had come to the conclusion early in that it would be very difficult for the United States to win the war.In Vietnam, there was so little to build on. The enemy was relentless. It was a guerrilla war, and the Americans came in the like elephans fighting mosquitoes.

"So I found myself in fairly sharp disagreement. I was one of those who felt early on that it was worth the effort. . . . You don't find easy answers, but I think there is something called

I have a feeling that people reading this book will ask themselves, 'What would I have done if I had been there? How would I have reacted?'" Bernard Kalb says.

The real last ambassador in Saigon, Graham Martin, was a difficult man to know. He avoided most reporters. Few had ever even met him during the war, although he did become more accessible once he returned to Washington.

The Kalbs' fictional last ambassador resembles Martin up to a point. But there are differences. Their diplomat, Hadden Walker, is tested more than martin ever was. Walker has a passion for porcelain, and porcelain plays a key role in the book.

Bernie Kalb happens to be an avid collector of Asian porcelain.

In some ways, Bernard and Marvin Kalb could not be more dissimilar.

But they also have much in common. Both have had distinguished careers in television, leaving CBS together in 1980 to join NBC. They worked their way up from a relatively humble background.

Their father, Max, was an immigrant tailor from Poland; their mother was from the Ukraine. Both parents were Jews and fled from repression. Max set out from Poland for London early in this century but somehow got shunted onto a ship which ended up in Galveston, Texas. From there he went to St. Louis, Rock Island, Ill., Chicago, and, finally, New York. At the outset, he did not speak English. But he soon learned the language and moved from the sweatshops to become the owner of his own dry cleaning store.

Both Marvin and Bernard went to New York's City College. During World War II , the elder brother, Bernie, ended up on the Aleutian Islands working for a GI newspaper. Dashiell Hammett, the detective story writer, was his editor. (Bernie describes him as "a bayonet of a man -- tall, thin, with a constant glint of a smile.") Bernie went on from the Quonset hut in the Pacific that served as a wartime city room for the New York Times and CBS.

Marvin, meanwhile, studied Russian history at Harvard. After getting his master's degree, he ended up in his US foreign service in Moscow. When he returned to Harvard to continue work toward his PhD, he found that the university was too quiet, too slow moving, for his increasingly cosmopolitan tastes. He tried CBS News. A hard-nosed editor tried to get rid of him by assigning him a summer sports-writing job with demanding hours. The hours were midnight to 8 a.m. Little did the editor know that Marvin Kalb was a sports freak. He conquered CBS.

Today Marvin Kalb doesn't look or act much like a sportswriter. He is scholarly, reserved, well-read, authoritative-sounding.

In contrast, Bernard Kalb is earthy, exuberant, avuncular. He likes color in his shirts and ties. One of his favorites is an orange tie matched by an orange handkerchief.

Bernie's taste in porcelain is wide ranging, but one suspects that what he treasures most are the rough and spontaneous patterns of the 16th-century Swatow porcelain from the south China coast.

Much of Bernie's collection of porcelain would never merit inclusion in a museum. He is fond of saying, "My shelves are filled mostly with enthusiasm." But he does care deeply about some of his pieces. When he was in Saigon once, for example, staying at the Caravelle Hotel, he carefully placed one porcelain vase which he had purchased behind a wall in the bathroom each night, thinking that this might provide extra protection for the vase should a rocket hit the hotel. The vase was better protected than he was.

Writing for the magazine "Antiques World" last year, Bernie described how he made his first purchase of porcelain in Hong Kong in 1968: ". . . I felt the vase stalking me everywhere I went; it was stamped into my mind. . . . I left the shop, I returned to the shop. I returned every day for a week; escape was impossible. I surrendered -- with the feeling that some anonymous potter, a century ago somewhere in China, had created a piece especially for me. I had crossed the porcelain line."

Similarly, for many who were there, Vietnam refuses to allow escape. As a country, it, too, had its beauty. It haunts. It raises questions.

Marvin Kalb thinks that many Americans are still groping, almost subconsciously, for the answers to those questions.

The key question, he says, is "whether the American people and their representatives have the muscle and will that's needed to sustain a confrontational policy toward the Soviet Union."

The "Vietnam syndrome" -- the national mood which has reacted against renewed foreign involvement -- has obviously diminished. The election of Ronald Reagan seems to mark a turning point toward a more assertive foreign policy. But there is still much caution on the part of many Americans when it comes to the question of sending American troops to fight overseas once again.

"I have a feeling we are living through legacies of Vietnam that are not quite defined yet in the popular mind," says Marvin Kalb.

One thing he is fairly sure of: Americans are increasingly willing to honor the veterans of Vietnam. He notes that several thousand persons turned out in South Boston, Mass., recently to dedicate a granite monument to the memory of 25 men from that community who were killed in Vietnam.

"I have a feeling that the mood of the country is turning, and that people will not look with disdain on a soldier who went to fight in Vietnam," Marvin Kalb says.

"I don't think an American soldier should be held contemptible for that."