NOT since the fateful lightning of four terrible Civil War years has there been as divisive an American venture as the Vietnam war. Vietnam divided families, generations, political parties, college campuses. It shattered the popular consensus, following World War II, that the United States always steered the right and virtuous course. Statesman George Kennan called it ``the most disastrous undertaking in our entire 200-year history.''
When Saigon fell in 1975, Vietnam fell from public view. American leaders bade it good riddance.
But the Vietnam war is resurfacing. Recent films such as ``Platoon,'' ``Full Metal Jacket,'' and ``Hamburger Hill'' are matched on TV by the series ``Tour of Duty.''
But it's on campus - the original seedbed of antiwar protest - that Vietnam is having its biggest comeback. The war - and the 1960s - are hot new research topics in history and American-studies departments. Courses on Vietnam have jumped from two dozen in 1985 to about 420 today. Political science classes, when dealing with Middle East and Central America policy, often dwell on the Vietnam war for days.
Laura Crosby, a 1987 Harvard grad, says Vietnam came up ``again and again'' in government studies. ``My senior thesis was on Cambodian refugees. There, it's clear the aftermath of the war goes on. We pretend it's over. But it's not.''
The new focus of study is causing debate in colleges, and especially in high schools. Most scholars agree that an understanding of the Vietnam experience is critical to an understanding of America today - and in the future. But, like the perennial question about teaching values in schools, the question about the Vietnam war is ``Whose version do you teach?'' The disagreements that marked America's involvement in Vietnam are resurfacing along with the war:
Was the war a mistake? Was the policy of ``containment'' wrong? Or have events in Southeast Asia proved the domino theory correct?
``There's a cottage industry called `the lessons of Vietnam,''' says former Johnson White House official Ben Wattenberg, ``and so you get both hawk lessons and `progressive' lessons in schools.''
War-year liberals and conservatives alike are concerned about how a new generation - most of whom were in diapers during the Tet offensive, and who are often described as ``ahistorical'' - will interpret Vietnam.
``People trying to control the future are also going to try to control the past,'' says Peter Braestrup, editor of the Wilson Quarterly, and author of ``Big Story,'' on Tet.
Writers like David Halberstam tend to represent the classic liberal view on campus: that the war was a tragic flaw in the American character, a result of an ``arrogance of power'' soon to be matched by an ``arrogance of affluence'' that has allowed the US auto industry to be outwitted and eclipsed by Japanese companies.
A classic conservative view may be summed up by US Education Secretary William Bennett, who said in 1986 that if the history of Vietnam were taught properly, students would not oppose American intervention in Central America.
Because of the war's complex origins, history has not produced a consensus view on it. Teachers and scholars look into the well of Vietnam - and see their own reflections. Myths beget myths. Cal Ellis, a Fulbright scholar who studied and lived in Saigon from 1967 to 1975, says, ``After eight years, I finally decided you could take any position on the war and argue it coherently.''
Take, for example, public support of the war: Stanley Karnow, an author whose ``Vietnam'' is a leading college text (and the basis for the 1983 PBS television series), argues that majority support ended in the fall of '67. Mr. Wattenberg, however, says polls show that the majority supported all ``seven long years'' of the war.
Hindsight also conflicts. A 1982 Gallup poll found that 72 percent of the American people felt ``the Vietnam war was more than a mistake; it was fundamentally wrong and immoral.''
At the same time, a 1979 Louis Harris poll showed that more than 90 percent of Vietnam veterans were glad they served and would serve again if asked.
(The poll also found, contrary to popular ideas, that the public does not harbor grudges against Vietnam veterans, or see them as dispossessed drifters. Just the opposite: On a ``respect'' scale of 1 to 10, the public rated draft evaders 3.3; protesters, 5.0; TV newsmen, 6.1; medics, 7.9; and combat veterans, 9.8.)
Walter Capps, whose course on the impact of Vietnam is the most popular at the University of California, Santa Barbara (1,400 students sign up for 900 spots), and who has conscientious objectors discuss Vietnam with veterans, says the purpose of his class is not to decide whether the US should have been in Vietnam.
``The Vietnam war is a fact, and not a debatable fact,'' Dr. Capps says. ``It had a tremendous impact on how we understand ourselves - our values, our `American soul.' That's the education students need ... to help heal the divisions.''
Allan Brinkley, who teaches a seminar on Vietnam at Harvard, says Vietnam is now history, and should and can ``be taught objectively, and dispassionately - like any other period in history.''
Evidence shows it is not. Mr. Karnow recently sat in a seminar at Yale where the professor, ``obviously a product of the 1960s,'' taught the war as ``a conspiracy between the CIA and Wall Street. I was appalled.''
Bob Pickus, director of the Quaker World Without War education organization, says the ``vast majority'' of the several hundred high school curricula dealing with Vietnam do not face up ``to the realities of the war. You only get half the evil.'' American war policy is rightly criticized, but then ``Hanoi's view of the war is adopted - a propagandized view that teaches kids America is the only villain in world politics. That's not a sound basis upon which to build a peace movement.''
Activist groups on the left are designing more curriculum than those on the traditional right. Experts say supporters of the war are more apt to want to forget it today. Karnow takes issue with the expression ``Vietnam syndrome.'' Syndrome, he says, means ``mental disorder.'' ``It's not a disorder that we should question the government after the war. The problem was, nobody questioned it early enough.''
Karnow's highly influential TV history is itself questioned. David Chanoff, co-author of ``Jaws of History,'' former South Vietnamese Ambassador Bui Diem's new book, says the film is ``a disaster.
``The `interviews' with North Vietnamese officials were based on questions submitted in advance. The producers were so excited about the officials that they got manipulated.''
After the film ``Full Metal Jacket,'' Prof. Herbert London of New York University was so angry with the depiction of Marine camp that he actually visited Parris Island, S.C. ``I lived in the barracks. I investigated the DIs [drill instructors]. To suggest Marines turn nebbish kids into psychopathic killers is totally at odds with what occurs. It's no wonder the official North Vietnamese history says the war was won in Washington.''
Film distorts history, says author Braestrup. ``You can't show motivations.'' While a flood of material has been written on the war, he adds, there's not enough scholarship. ``We have oral histories and journalism, but we lack the serious mainstream history, like that on NATO or politics, upon which to teach Vietnam.''
Scholars are opening new areas. One recent study shows that, unlike the popular image of constant jungle warfare, most GIs spent a lot of time sitting around. The ratio of support to combat troops was 9 to 1.
The roots of the war are also getting more scrutiny - particularly the issue of communist influences. The popular view is that the US mistook North Vietnamese nationalism for communism - and overreacted. Recent scholarhip shows the two were closely linked (``nationalism was defined through communism since the '20s,'' says Dr. Brinkley) and that the supposed independence of the Viet Cong is a myth.
Political studies show that the US did not enter Vietnam on cocky assumptions - leaders knew all along it would be a grinding war.
Ronald Steel, author of the definitive biography of Walter Lippmann (the first major journalist to oppose the war), says Vietnam represents the end of the strictly bipolar world. ``How can you teach kids today that the struggle against communism is the most important moral issue? We're cozy with Angola and Mozambique. We'd love to have China take over Vietnam!''
Vietnam veterans have played an important role in classrooms, getting across the atmosphere of the war years to students. (``Texts don't give you the cultural feeling of the '50s that most of us grew up in,'' one high school teacher, a veteran, complained.)
Dr. Capps says the common feeling about the war by vets is that it didn't have meaning as it happened. ```It don't mean nothin',' they'd say when coming home.'' Speaking to students about Vietnam helps to define meaning on both sides, Capps says. ``The vets act like sentinels. You teach into a context when they are there.''
Phil Straw, a one-time marine and now a congressional aide, teaches an honors course on Vietnam at the University of Maryland, in a ``living history'' mode. People like George McGovern and William Westmoreland address the class. Each student interviews several vets. Mr. Straw's passion for the period made student Yesmeen Day realize, ``Vets give it human perspective. You realize it was about Vietnam and America.''