THE SITUATION IN El Salvador involves a question of whether a country can undergo its own social revolution free of external influence. Though this should be allowed to happen, it will not--thanks to our friends in Moscow, Havana and Managua.

Critics of the Administration's policy advocate an end to U.S. military assistance to El Salvador, preaching compassion and invoking the right of the nation to choose its own destiny. They would do this as that Central American nation descends further and further into totalitarian rule. Whether one views the situation from a moral perspective or one of realpolitik, our imperative is clear: to do what we can to ensure the Salvadoran people a voice in their own affairs.

Liberal criticism, if less strident and more focused than that of the majority opinion, can help temper U.S. conduct in El Salvador. Critics must insure that El Salvador remains a non-military political problem and the solution primarily a political-economic one. Specifically they can help insure that we use our support of centrist President Jose Napoleon Duarte to pressure him to halt the excesses of the far right, plan for free elections, and go ahead with far-reaching land reforms.

If Vietnam taught us something about the limitations of American power abroad, it also proved that in conflicts abroad, the line between good and bad often becomes amorphous. It is thus ever more important that we be honest with ourselves and confident in our purpose. If we really believe in the dignity of the individual and freedom for all people, we will demonstrate it in El Salvador. What we have to do there will not be pretty and will not sit well with the national conscience. But it is what we must do.