AS A SOCIETY, we have some curious notions of what foreign enemies to concentrate on keeping from the gates. We spend tens of billions of dollars a year to prevent nuclear war: a terrible peril, necessarily of compelling priority, but a very abstract peril all the same. The president can spend what is, in a political sense, an even more precious commodity -- his claim on the public's attention -- to point up the perceived dangers of Marxism in Central America. Meanwhile, though it is not ignored, another international matter whose menace is far more immediate, real, costly, terrifying and pervasive is treated as almost routine.

We refer to drugs, most of which are produced abroad. Nothing else in the world damages this country and its citizens more -- in lives lost and blighted and in other economic and social costs. Yet our official and national attention to it is fitful and compartmentalized. The drug trade seems to ebb and flow as a law-enforcement priority. Until very recently, it was not regarded as a crucial consideration for American diplomacy. It is still possible to read whole books and learned articles on Latin America and other drug sources without seeing a mention of the dread flow. Cobalt engages the strategic thinkers, not cocaine.

Suppose the Mexicans were sending guerrillas across the border to raid ranches in Texas, occasionally killing an American. Suppose the Russians were sending frogmen on a like mission to isolated Aleutian islands. It is not hard to imagine the adrenalin that would flow as the country contemplated these affronts to American sovereignty and tranquillity. Yet thousandfold multiples of these effects arise from the drug trade with no remotely similar political or emotional swell.

True, the "raiders" now crossing the border have not been dispatched or, presumably, winked at by their governments -- although Reagan officials question whether Cuba and Nicaragua are as innocently detached as they claim to be. Especially in Latin America, the source and conduit countries are themselves increasingly ravaged by drugs. Drug use grows within their borders. The drug business has created centers of wealth and power challenging the integrity and, as the United Nations recently put it, "the very security" of some countries. It becomes increasingly necessary to define drug abuse not just as an overwhelming health and social issue but as a revolutionary political force of global dimensions.

We have no inclination to dump all the blame on the producing countries -- friendly countries, after all. They are in the grips of a monster created in the first instance by the immense demand generated by the American market. We are certain, however, that a basic condition of wise policy is for the problem to be given a measure of attention and respect no less than that accorded nuclear war and Central American guerrillas. Even at this late date, the first requirement is thinking about drugs, urgently, comprehensively, correctly.