The blood is usually pretty slow to boil in our business when it comes to assailing each other's work. That may explain why it took Robert Elegant, a veteran Vietnam War correspondent, 15 years or so to look back "coolly" and conclude in the August issue of Encounter magazine that distorted, biased and ignorant news coverage pretty much accounted for the defeat of American and Vietnamese forces.

Not until October did another veteran of Vietnam, CBS's Morley Safer, get on the air and belt Elegant and Encounter for work worthy of Goebbels or "a Soviet department of agitation and propaganda." And another month passed before columnist William F. Buckley Jr. weighed in with a resounding vote of confidence in Elegant and a denunciation of Safer, whose performance he found "shocking."

It is now December. But better late than never to address an issue that, as Elegant defines it, is far too important to be reduced to a spit-spat over who lost Vietnam. For it is Elegant's conclusion, not just that the "media" lost Vietnam, but that they remain afflicted by a "Vietnam Syndrome" which, for as long as it lasts, will make it "virtually impossible for the West to conduct an effective foreign policy."

Elegant has a point in saying that "no Western power can conduct a foreign policy that, of necessity, relies in part on the threat of military power and, upon occasion, on the exercise of military power if the media reflexively denounce almost any use of armed force."

But is that what we're up against today? Exhibit A in Elegant's argument is El Salvador, where, he believes, "throughout the Western world, commentators and reporters have invoked the specter of Vietnam to arouse detestation of a Washington initiative." That simply isn't so. A great many honest arguments can and have been made against the Reagan administration's support for the Duarte government in El Salvador that have everything to do with the particular nature of that conflict, and only marginally to do with Vietnam analogies.

More to the point, there is a valid Vietnam analogy--a lesson that is strictly applicable. The U.S. effort in El Salvador is limited; there is an element in it of psychological warfare that is not an easy weapon to employ in an open society. To be effective, it requires demonstrable public confidence in the American purpose, a trust in the administration's presentation of the case, and a show of national will in a way that would make threats to Nicaragua, Cuba and/or the Soviets an effective deterrent to their support of the Salvadoran insurgency.

Elegant contends that the American media's "Vietnam Syndrome" makes all of that impossible. But this would suggest that somehow the American public has been denied access to the administration's side of the argument. And that is no more true of El Salvador than it was true of Vietnam. There, the effort also was supposed to be "limited" and the government had not the slightest difficulty reaching the public with reassurances on that score.

The U.S. involvement, we were told, would require only a handful of military advisers (not engaged in combat). The number quickly grew to 25,000 (in combat, taking casualties). A war that wasn't supposed to require organized American combat units at all ultimately required 1.6 million combat troops and cost more than 57,000 of them their lives. A war whose successful conclusion was regularly and confidently predicted, instead dragged on and on.

Surely the ensuing erosion of public support, so essential to the limited purpose of message-sending to Hanoi, was not wholly the work of a cynical, clubby, ideologically disoriented, sensation-seeking press corps, toadying to its bosses or the intellectual elite, as Elegant would have us believe.

Some part of the public disenchantment had to have owed something to government miscalculations, which in turn gave rise to broken promises, false hopes and unfulfilled progress reports. And some part of the opposition to the Haig-Reagan policy for El Salvador and Central America, similarly, has to have as much to do with an unconvincing presentation of the case that anything constructive is being accomplished as it has to do with a lingering "Vietnam Syndrome."

I don't exclude the latter. But to suggest that's all there is to it is to ignore the inevitable burden imposed on American policy-makers by the necessity of having to take public sentiment into account. That's not a "syndrome." It's a fact of life in open societies that even a president with Ronald Reagan's reservoir of public trust cannot ignore.