"M*A*S*H" floated for its 11 years in a haze over which war it was about. Ostensibly, it was set in Korea, where a war was fought from 1950 to 1953, one little known to most of the series' audience except perhaps as history. But the series drew its currency and impact from its viewers' awareness of Vietnam, a war they were viewing simultaneously as daily news or holding in recent memory. This confusion of one war with another was never more evident than in the last show.

In a crucial scene, the 4077th's loudspeaker reports the Korean war's overall casualty toll: it is 2 million. It is a figure suitable to both the armistice with which this series about war ends and to its anti-war theme.

I wondered why a similar device could not have been used to state a few other truths of the Korean war: that the United Nations' share of the casualties was incurred in the course of repelling a clear communist aggression; that the allies succeeded in restoring the territorial line that the enemy had broken, and in establishing that their hundreds of thousands of North Korean prisoners would not be sent home against their will; that South Korea subsequently became the friendly, growing though still repressive and authoritarian country (leagues freer than North Korea, nevertheless) it is today.

It is characteristic of the glow that bathed the "M*A*S*H" farewell that Newsweek opened its cover story by quoting this dialogue: a correspondent asks "Do you see anything good at all coming out of this war?" and Hawkeye responds, "Yeah, me alive. . . . That would be nice." But general and particular good did come out of the Korean war. Notwithstanding its costs and frustrations it was a just war, and measured by its proper limited aims it was a successful war too.

Twenty years later came Vietnam. Many people, including those who sample and make the public's taste in prime-time television, were evidently convinced there was no such thing any more as a just or successful war.

By 1972, when "M*A*S*H" opened, the Vietnam War was being widely seen as a mistake and an agony. If its professed aims were acknowledged, they were commonly dismissed. Being "against the war" was on the way to becoming "anti-war," an assumption that no war involving the United States could be legitimate, except in the starkest self-defense.

From life--from the Vietnam-era news--the new series took the notion that war was a theater of irony and horror divorced from comprehensible public purpose. From art--the Catch- 22 tradition --it took its marvelous close-to- the-bone black humor. This was the world of "M*A*S*H."

In the last episode, an American tank (parked sneakily under a Red Cross tent) draws hostile fire upon the hospital compound. A guilt-stricken Hawkeye has recently intimidated a fellow passenger on a bus into suffocating her crying child so as not to give the bus away, and now he exposes himself to danger and drives the tank (into a dump) out of range.

The element of personal redemption is strong. Otherwise, the scene's plain implication is that the American presence is what has caused the shooting, hence the war, to go on. This is consistent with the judgment conveyed by the show (and held elsewhere) that the American departure would be a blessing not only for Americans but for the Vietnamese staying behind.

By a nice coincidence, the readers of this newspaper had an opportunity to test that judgment on the day before and on the very day of the last "M*A*S*H" episode: in the absorbing reports on Vietnam and Vietnam-occupied Cambodia by Elizabeth Becker.

Defeated, the Americans withdrew, but the war went on, and the two countries have since suffered variously, tragically, mostly at their own hands. Vietnam today, one Becker source says, is "probably the most backward, the most poor major country in the world." In Cambodia the revolution killed perhaps 2 million people and now, Becker says, the country is "sinking again."

Why did the creators of "M*A*S*H" fold the tent? Was some part of their fading creativity a seeping consciousness that what Indochina's victors have made of their triumph does not fit easily with the self-indulgent, American-centered image of the war presented on the screen?

I see you protesting: it is unfair to expect a popular entertainment to address questions that have proven too difficult, too dark for full airing yet in more sober precincts. All right. "M*A*S*H" was terrific television and it had truth to tell. But it traded on the form of one war, Korea, to approach the substance of another, Vietnam, and left much truth untold about both.