My son has just left the "it is not fair" phase of his life for one that has not yet announced itself. Before things were constantly not fair, though, they were crushingly unimportant. This was his "so what, who cares" phase, and he said that so often that in my house it was called by its initials--"SWWC." This is just one way you save time in a household with two careers and lots of plants to water.

SWWC came back to me the other day when it was announced, in various places, that unless we granted El Salvador another $60 million in military aid, it would fall to the "rebels," a word the State Department uses to mean "commies." Honduras will be next, and then, to the south, Panama, and to the north, Mexico. That not only moves the Red Menace closer to home, but imperils some pretty terrific beaches.

By now of course, you recognize that this scenario under another name is the old Domino Theory. It was trotted out the other day by Thomas O. Enders, assistant secretary of state for inter-American affairs, and Nestor D. Sanchez, deputy assistant secretary of defense for inter-American affairs, and seconded by Sen. Henry Jackson (D-Wash.), who also thought the red tide had to be stopped in El Salvador lest it lap upon the shores of Mexico.

Someday someone is going to explain why dominoes are supposed to topple only one way, to the left, and why it is that we can not get them to topple our way, to the right. And then when that is explained, that same person also will have to explain why the dominoes did not fall as they were supposed to in Southeast Asia. If the Vietnam war proved anything, it was that countries really are not dominoes. Vietnam toppled and with it Laos and Cambodia, but they already were engulfed in what amounted to the same war, while Thailand, Burma and the rest of Southeast Asia remained--and remain--standing tall.

But none of that has to do with SWWC, which assumes that El Salvador will "fall" and then some other Central American countries will follow. It is at this point, if you are asking questions, that you have to ask if not both "so what" and "who cares," then at least "so what?"

I ask that not out of callousness and not without realizing that the agrarian reformers now in the hills may turn out to be as much a bunch of thugs as the guys now in their various presidential palaces, but because there is an assumption that all these states would be little Central American duplicates of the Soviet Union.

But would they? Would El Salvador be Marxist like the Soviet Union, which is our enemy, or Marxist like China, which while not quite a friend certainly is not an enemy, but which was (look it up) the reason we fought in Vietnam.

Maybe these Central American states would be Marxist like Yugoslavia, which is neutral, or maybe they would be Marxist like Albania, which for a while aligned itself with the Soviet Union and then later with China and now has decided to disappear down a European black hole and cease to exist.

And even if all the Central American countries should go communist--each and every one of them--does that mean that we have to kiss the Panama Canal goodbye? Cuba is not only Marxist, but hostile as well, and has been both for a long time now. Yet we maintain a naval base at Guantanamo Bay. As hostile as the Cubans are, they dare not attempt to take the base, although it's likely that this is one lease that is not going to be renewed.

Time and time again the administration cautions us that El Salvador is not Vietnam and they are surely right in this. It is a different country in a different region and neither the Congress nor the American people will allow it, in terms of either troops or funds, to become another Vietnam.

But where El Salvador is like Vietnam is in the attempt to control from Washington events taking place in remote hamlets, to see an ancient struggle only in terms of east-west rivalry and last, to fail once again to appreciate that for silly reasons of our own we wind up either exacerbating or prolonging a war and fooling with the lives of others--the people of El Salvador. More of them than need be will die for our failure to ask, "So what, who cares?"