Bumping into former senator J. William Fulbright the other evening, I dutifully asked him the question of the hour: Is El Salvador another Vietnam? The brow beetled familiarly. "Sounds like Vietnam," he said. And you know, he's right. There is a great tussle over whether Salvador is another Vietnam and over just what "Vietnam" means. The undeniable core of the legacy, however, is the vocabulary in which foreign involvements are now discussed. Salvador does sound like Vietnam.

We all know the words, the images, the allusions, the respective nightmares invoked: on one side one hears of a Soviet/communist advance, revolution and Marxism on the march, arms-running and aggression across a border, the toppling of dominoes, a challenge to the prestige, credibility and eventually even the physical security of the United States: debacle.

From the other side one hears of authentic revolution and social justice, of bloodshed, division and disgrace, of escalating cost and inconclusiveness: quagmire. But you get the idea: it is the mirror of the other side's view.

Some of us, to be sure, nod in assent at the sound of one or the other litany. But don't a great many of us groan and turn off as soon as these words begin to flow? I certainly do. I hear them and think that the people speaking, on both sides, are pushing buttons meant to elicit a certain mechanical response. But the buttons are not wired to reality--to the messiness, incompleteness, perversity and uniqueness of the situation on the Salvadoran ground. The vocabulary of Vietnam plays us false.

President Reagan has recognized the evocative power of "Vietnam" by summoning up all the geopolitical specters he associates with the word in order to build support for his policy, even while denying ("there is no parallel whatsoever with Vietnam") the prospect of a widening war. But he only legitimizes the metaphor and invites others to summon up their specters of choice and project them large ("Vietnam is in the air, and everybody knows it") on the screens of their particular political views.

I think it blurs our vision and warps our debate to attempt to expropriate the slippery, contentious, multi-faceted imagery of Vietnam for the purposes of Central America. The wounds of the earlier conflict are still too raw. No usable consensus yet exists from which Americans might draw a common meaning.

For me, one index suffices to demonstrate the futility of comparison. Currently in El Salvador there is one American adviser for every 13,000 American soldiers present at the peak in Vietnam. Granted, now we lack the draft, which energized so much of the opposition to the Vietnam war. But you have only to look about you to see the compelling and restricting power of the general awareness that in Vietnam, too, things started small.

Why not take Salvador as a vexing problem of generally modest dimensions that deserves to be taken seriously but not as the most serious crisis in the world. It is worth paying something for, but not an unlimited amount.

America's global position always calls upon it to do more than it otherwise might, but in El Salvador, a proportion must be preserved between the American effort and the effort made by the Latin places in whose name some substantial part of the American effort is being made. Nor need a solution be perfect from anyone's point of view.

Such a framing of the problem does not support the great stakes that the president, in his frustration, is now assigning to El Salvador. Neither does it support the contrary notion that the United States has no real interest in how things finally come out and had just as well be "realistic" and let the guerrillas, uncontested by us, prevail.

Meanwhile, let us not be distracted by grim and mostly fanciful echoes of Vietnam. Let us call the place where we are now involved by the right name, flat and uncertain as it is: El Salvador.