LIKE A DISEASE out of remission, the Vietnam malignancy returned to television screens last Saturday, as dangerous and insidious as ever. The story was a new twist on an old tale--how American public officials lied to each other and to the public over the course of the long war. Specifically, a CBS documentary ("The Uncounted Enemy: A Vietnam Deception") showed how the U.S. military successfully strove to "supress and alter" estimates of Communist forces in Vietnam before the January 1968 Tet offensive.

The program was compelling in its indictment of the generals and politicians who valued good news more than unpleasant truth. General William C. Westmoreland, commander of U.S. forces after 1964, told the president and Congress in 1966 and 1967 that there was going to be progress in the war, and, by God, he saw to it there was progress--at least on paper, that is. The program depicted Westmoreland and the yes-men around him as malfeasors dedicated primarily to saving their own skins. The implications of their misdeeds, according to the documentary, were startling. "The fact is that we Americans were misinformed about the nature and size of the enemy we were facing," correspondent Mike Wallace said, because of "a conspiracy at the highest levels of American military intelligence." Because we did not know how many troops we were fighting, goes the damning implication, we could not fight properly, we lost the war.

And that is where the documentary--and much current thinking about Vietnam--goes astray. The disastrous American intervention emerged not as an ill-advised adventure doomed from the start, but as a mammouth screw-up. It ended in failure not because America tried to suppress a civil war it could neither control nor understand, but because the military hierarchy malfunctioned and the civilians in command lacked the will power to force matters to a successful conclusion. If only we had not "fought with one hand tied behind our back," America would have won this war just as it won all the others. Yorktown, Midway, Normandy, Da Nang--they're all the same. But this argument, implicit in the documentary and explicit in the statements of Ronald Reagan and others, reflects a dangerous tendency both then and now.

American boys went to Vietnam to stem global communism; we preferred, understandably, a pro-West government to achieve this goal. We propped up a dubious regime in the southern part of the country and called it the Republic of South Vietnam. Our objective, then, was to legitimize this government, a difficult, perhaps impossible, task. But the hit-parade of generals and petty tyrants in Saigon possessed little popular support, no traditions of political leadership, no real boundaries and no mandate to govern from its people. We gave the Vietnamese the shadow of representative government but not the substance; as many Americans freely admitted, the national elections mandated by the 1955 Geneva conference would probably have propelled Ho Chi Minh into power--a likelihood that we and South Vietnam's aspiring bosses were unwilling to accept. So America chose to keep the country divided, and substitute military power for genuine political authority--for the latter was not ours to give.

We plied Vietnam with more arms and cash (which rarely reached its intended beneficiaries) than it could handle. And--since the Vietnamese could not do the job alone--our "advisers" and later our troops would rout communists from the political "infrastructure" and preserve our control of the presidential palace. That theory justified escalation after escalation for 12 bloody years, through more than 57,000 American and an estimated 1.5 million Vietnamese deaths. Ultimately, we were in Vietnam not to "win" the war--for Tet hammered home the realization that this was unrealistic--but to attain "peace with honor," a euphemism for an agreement which would allow us to withdraw our troops and preserve face.

THE CBS DOCUMENTARY did isolate a crucial military issue in the war--an issue which symbolized the fraudulence of our effort in Vietnam. Because, unlike in previous wars, we were fighting to hold ("pacify") territory, not seize it, the determining factor in our success or failure was the level of opposition in the south; Wallace called troop infiltration to the south "the most critical factor in the war." The Vietnam era--the go-go '60s, when the computer embodied all that was sleek and modern about America--had an obsession with numbers, and Robert S. McNamara installed his B-School brand of systems analysis in the Pentagon. There, he and his elite corps tried to guide the war by the cold, hard, objective numbers.

Making the numbers look better became the chief objective of the war. Those charged with evaluating the battlefield situation felt compelled to prettify the picture to please their higher-ups. Accurate but unpalatable reality was not in demand; visions of success, however far-fetched, were. When the body counts reached Washington and the Oval Office, they inevitably showed relatively few friendly casualties and massive enemy losses. So we must have been winning, right?

The story of how Westmoreland and others played the numbers game is tellingly laid out by the documentary. One government analyst, Richard McArthur, recalled that his estimates of enemy strength had been halved by superiors while he was on vacation. The U.S. commander in charge of producing the official estimate of enemy forces sent to the Pentagon and the White House wrote to his wife in March 1968, shortly after Tet began:

We started with the answer, and plugged in all sorts of

figures until we found the combination which the

machine could digest. And then we wrote all sorts of

estimates showing why the figures were right which we

had to use, and how we continued to win the war.

Such distortions led to top-level government decision-making that had little basis in reality. Former CIA agent Sam Adams, whose disclosures prompted the CBS investigation, recalled reading a captured document indicating enemy troop strengths ten times higher than U.S. estimates. The bankruptcy of the reporting system helped tint the rose-colored glasses which could allow President Lyadon Johnson to declare in March 1967: "General Westmoreland's strategy is producing results [and] our military situation has substantially improved."

Wallace produced one of the most effective moments in the program when he confronted Westmoreland about his distortion of the enemy troop estimates in the wake of the Tet offensive. Wallace showed that, according to the government figures at the time, the entire North Vietnamese army had been wiped out in Tet. This was, of course, absurd; the North scored an important tactical victory by demonstrating the ability to stage attacks simultaneously in every important South Vietnamese city, and in any case went on fighting for some time thereafter. What the documentary failed to mention, however, was that the illogic of Westmoreland's math was known to the White House at the time. At a meeting of the "Wise Old Men," brought together to consider the implications of Tet in March 1968, former U.N. ambassador Arthur Goldberg pointed out the impossibility of the army's figures. U.S. leaders knew the information behind their Vietnam strategy was riddled with inconsistencies but chose to overlook their gloomy implications. So the battle--hopeless, pointless, endless--continued.

We fought on because we thought we could justify with our guns the rule of an illegitimate government; it was not merely a matter of screwing up, or civilians not letting the soldiers do their job. We lost because we could not win a war in which our objectives were impossible. The great danger in our failure to recognize our errors in conception (not merely in execution) is that we will begin to think that with better planning or more firepower we will get it right the next time. The next time, perhaps in El Salvador or some place like it, we may not lie about our figures and we may not go "half-way"--but we still will not win, only prolong the agony. That our troops are not yet in El Salvador can be attributed to a limited comprehension of the Vietnam experience, but that comprehension is rapidly fading. Only when we realize that brute force cannot cure the political, social and economic woes of a nation in upheaval will we have salvaged an honorable legacy from our years of dishonor in Vietnam.