The influx of refugees from Cuba has exposed another contradiction in the foreign policy of the Carter administration. For the administration sought to muffle confrontation with Cuba in a web of fuzzy ties with the Third World.

But the refugees challenge Washington directly. Behind the refugees, moreover, lies a catastrophic failure by the Castro regime precisely because of its Marxist commitments and its character as a Soviet satellite.

Fidel Castro himself confessed the failure of his regime in a remarkable, secret speech to the People's Assembly on Dec. 27. The speech was subsequently obtained by American officials. But it received almost no public attention -- a sure sign the United States had gone out of the business of embarrassing Castro.

The essence of Cuba's trouble is economic. Castro acknowledged that blight had ruined Cuba's main exports -- sugar and tobacco. Almost all the yield from the two crops went to finance petroleum imports from Russia. As a result, there were severe shortages of "foodstuffs, medications and raw materials." Castro even mentioned bread and beans as being a short supply.

Efforts to make do by local production have apparently been a fiasco. Castro spoke of defects in "towels, bed sheets and mattresses." He referred to a clothing factory built in record time that produced trousers prone to tear and shrink. He spoke at length about inefficiency and corruption among party officials, about labor absenteeism and about consumer greediness -- even to the point of tapping electric line for private use. He said that in consequence of the economic failure, Cuba had "tens of thousands of youths out of work."

When it came to solutions, Castro sounded almost desperate. He toyed: with, but rejected, the idea of a new burst of revolutionary zeal: "We do not want to launch a cultural revolution." He took a couple of shots at the Soviet Union, deploring the "many products which we cannot get from the socialist bloc" and sarcasticaly suggesting that maybe "10,000 Cuban workers" could be sent to "produce lumber in Siberia."

For lack of anything better, he came down hard for belt-tightening and efficiency. "We are in a terrible world crisis," he said. "We cannot conceive ambitious plans."

In retrospect, it is clear that the flow of refugees was set in motion as a partial response to the crisis. Castro first moved to drive out surplus labor, especially unmarried males, who represent the great potential for dissidence. He has since tried to maneuver the flow in ways that work to discredit the United States as unreceptive to Cubans.

The initial response of the Carter administration followed the policy of not getting crossways with Castro. It breathed the same spirit that led to negotiations toward recognition of Cuba, that minimized Cuba's pro-Soviet role in Africa and the Caribbean, and that looked the other way at the time of the Russian combat brigade in Cuba.

In that same spirit, the administration started to treat the Cuban refugees as if they were refugees from anywhere else -- not subject to special consideration because they were fleeing Castro. That approach was dropped when the Cuban community of south Florida, with help from the governor, put pressure on Washington to have almost all the refugees accepted as persons seeking political asylum.

When Castro took advantage of that offer to crowd in criminals, lepers and undesirables, the president reversed himself again. Yesterday, Carter barred all further Cuban refugees until an organized sea-and airlift could be worked out with Castro.

Earlier, Washington had moved to "multilateralize" the Cuban refugee question at a meeting of a score of countries in Costa Rica. The session there sought to concentrate upon Castro the condemnation of the international community. The idea is that he will be shamed into better behavior by the disapproval of other countries -- espeially neighbors in Latin America.

But even if that those tactics work -- which is highly doubtful -- there is no ducking the basic fact that Castro's Cuba is different from all other Third World countries. It has been, and remains, a Soviet surrogate. It was a history of confrontation with the United States. It is only 90 miles away. So its refugees don't go to Thailand or Austria for eventual resettlement in the United States. They seek asylum here first.

If only to distinguish Cuban refugees from the thousands of other poor folk in the Caribbean who seek to better their lot in the United States, it is necessary to think about the Castro regime in the Soviet context. Within that context, one ultimate goal inevitably asserts itself -- making Cuba desert the bloc.

A new bout of confrontation may open one route to that goal. Perhaps it would be better to give Cuba the kind of help that would facilitate the shedding of a Soviet connection that is becoming increasingly distasteful -- even to Castro.

The outcome, however, is not really the point. The point is that in Cuban affairs -- as in every other single policy area -- there is need for a basic rethinking.