BERLIN -- There was a gala dinner here last week before Hope M. Harrison's lecture about the origins of the Berlin Wall in 1961. The chef of the American Academy in Berlin, Reinold Kegel, prepared a witty meal: first, Rostock fish stew with mussels, a typical East German dish; then, "Broiler," baked chicken on a bed of rice and peas with lecso relish; and finally, a "Divided Dessert." 

That turned out to be a meager but succulent slice of pineapple, a reminder of trade with Cuba, topped with whipped cream (there were plenty of cows in East Germany) and separated by a long thin cookie wafer (decorated in turn with delicate frosting to evoke the painting of the wall) from a rich chocolate mousse studded with pieces of banana.

This banana business is a kind of running joke among Berliners. Even before the wall went up, film director Billy Wilder ridiculed ubiquitous shortages in the East with a scene in his neglected classic "One Two Three:" a Potemkin bar in which an East German entertainer yodels a German version of "Yes, We Have No Bananas," chronicling a long list of shortages. When the wall came down, the West German government handed out bananas to the throngs of celebrating Ossies in Potsdamer Platz. 

Harrison's after-dinner talk was fascinating. Then it paid an unexpected dividend the next day.

Harrison is an assistant professor of history and international affairs at George Washington University and author of the newly-published Driving the Soviets Up the Wall: Soviet-East German Relations 1953-1961. She served as director for European and Eurasian Affairs at the National Security Council in 2000-01.

More to the point, Harrison is of the generation for whom the Cold War was not a real-time issue of conscience but an accomplished fact. She was born in 1963. 

As a graduate student, she flew into Berlin on November 10, 1989 -- the morning after the wall came down and spent the next ten days witnessing the euphoria that ensued.  She spent 1991-92 in Moscow and Berlin during the "golden age" of archival research, when almost everything in the Soviet records was open to inspection. (Many of those filing cabinets since have been locked up again.)

And the response to her book has been enthusiastic:   "A truly distinguished example of new Cold War scholarship," according to John Lewis Gaddis of Yale University, who is among the leading historians of the period. "As a case study of how a study of how a small power can manipulate a superpower, it is sure to become a classic."

Among the current generation of Americans, and for many Europeans, Berlin's experience is already fading, its story  something that was important once but now is little more than a half-remembered fact from a high school history book -- a little like the "Danzig Corridor" of the 1930s.

Berlin's odd status at the center of the Cold War arose at the end of World War II -- a war in which Germany had wounded Russia gravely, and which the Soviet Union had done more than its share to win. The historic capital was located deep inside the half of Germany that the Soviets insisted remain communist at the end of World War II.  So the city itself was divided into four sectors administered by the wartimes allies -- American, British, French and Soviet -- its western sectors connected to West Germany by road, rail and flight paths along three potentially fragile rights of way.

Thereafter Berlin remained a constant source of tension between the superpowers: the scene of a famous blockade and airlift in 1949, of a short-lived rebellion crushed by Soviet tanks in 1953, of a more or less constant hemorrhage of talented workers to the West.  By 1961 something like ten percent of the East German population had migrated through the city to West Germany. 

As Harrison's book shows, the East German government of Walter Ulbricht pushed the Soviets to let them do something to staunch the flow. Behind the scenes, the argument was relatively simple: cut the city off from the West and take it over altogether, or build a wall.

The Soviets were reluctant to challenge the Americans to a European war, especially after John F. Kennedy was elected president in November 1960. But at the same time, they understood Ulbricht's problem.

So in early 1961, the Soviets upped the ante in a bluffing game. Soviet Communist party chairman Nikita Khrushchev threatened to sign a treaty with the East Germans that would give the smaller nation the right to close Western access to Berlin. Kennedy then met Khruschev in June 1961 at a summit conference in Vienna and gave the Soviet leader two strong messages.

The US would tolerate no interference with Berlin. But almost anything else was okay. Khruschev signaled that the USSR would sign the treaty. It would be up to the US to decide whether that meant war.  Kennedy famously replied: "Then, Mr. Chairman, there will be war. It will be a cold winter."

Instead, the wall went up in August.  And for the next 38 years, the Russians kept the road open to Berlin, until 1989, at which point the entire Soviet-dominated system collapsed. 

Talking all this over with a friend the next day, I was startled when he made a swift connection between East German party boss Ulbricht and long-time South Vietnamese president Nguyen Van Thieu. His point was the same as Harrison's: that often allies are difficult to control.

But Ulbricht had been the villain of Harrison's story. It took a little while before I realized that my friend was simply reasoning backward by analogy. In the point he was making, the US was to South Vietnam as the Soviet Union had been to East Germany -- a superpower being led around by the nose by a repressive client-state. 

But then Vietnam was supposed to have been just the other way around, at least in the view of the original decision-maker, John F. Kennedy. (Ngo Dinh Diem was running South Vietnam in those days. Kennedy soon authorized a coup which led to Diem's assassination.)

In both cases, communists were thought to be testing American willingness to back a client state. In both cases, Washington was convinced that its credibility in a global struggle was at stake.  The "domino theory" was invoked. 

Vietnam even had a wall -- the "McNamara Wall."  The country had been partitioned north and south in 1956 along the 17th parallel -- the "Demilitarized Zone" as it became known. But North Vietnamese materiel and troops continued to move the south along the Ho Chi Minh trail. Announced in 1967, the McNamara Wall was to consist of electronic sensors and observation posts, extending deep into Laos and backed by all manner of military force. It was supposed to halt the southbound traffic.

It didn't work. It took another eight years and altogether nearly two million lives, but the North Vietnamese finally entered Saigon in 1975. The last Americans fled the country they had set out to "protect." Nguyen Van Thieu moved to Massachusetts and much of the rest of his government moved to Hawaii and California.

What I had learned from the conversation with my friend is that interpretations still differ widely as to what had happened in Vietnam in the past fifty years -- in Washington, in the world.

Later that day, I looked around on the Web at what the better colleges were teaching about Vietnam. The dominant view there was still very much as cultural critic John H. Tompkins of The San Francisco Bay Guardian once described it -- Vietnam seen as a rock opera, starring an endless array of American acts, supported by tens of millions of hardworking Vietnamese stage-hands.

The standard works on Vietnam itself appeared to be much the same ones that dominated 25 years ago when they were new, the books that opened American eyes to just how different was the case of Vietnam from that of Germany -- Alexander Woodside on Vietnam and the Chinese Model, David Marr on Vietnamese Anti-Colonialism. At least at first glance, the new generation of Vietnam historians (of whom there are many) has yet to break through. 

It was then that I realized was the history of Berlin was, indeed, history.  But, at least for the generation that took sides over it, the story of Vietnam is anything but settled. In fact, thanks to the sheer numbers of the baby boom voters who furiously debated the issues when they were young, it is once again a divisive issue in American politics. All the more reason, therefore, to pay attention to the scholars.