FOR many years the United States followed the concept of ''linkage'' in dealing with the Soviet Union. Under this theory, if the Soviets wanted concessions in one area - say, trade - they would have to satisfy US concerns in another area - such as emigration. After the 1979 Soviet invasion of Afghanistan, President Carter responded by freezing the entire US-Soviet relationship, slapping on a grain embargo, and withdrawing from the Olympics.
Under President Reagan, Secretary of State George Shultz changed course. While Mr. Shultz didn't deny that there were times when linkage was unavoidable, he pointed out that it had become a trap: It often put the US on the defensive, gave the Soviets the initiative, and made US diplomacy appear inconsistent. Issues should be dealt with on their own merits and relationship to US interests, he declared.
Thus, when the Soviets shot down a Korean airliner in 1983, Reagan and Shultz responded with a range of sanctions related to civil aviation - a limited civil-aviation boycott, closure of Aeroflot offices, and action in the International Civil Aviation Organization. They resisted calls for grain embargoes, refused to break off arms-control negotiations, and preserved science-and-technology exchanges. They were harshly criticized, but history has proven them right.
As of this writing, President Clinton appears to be following the same careful course in his response to the inexcusable Cuban shootdown of two civilian aircraft Feb. 24. He has suspended air-charter travel between the US and Cuba, tightened travel controls on Cuban officials, and expanded Radio Marti broadcasts. He also agreed to work with Congress on a bill that would tighten economic sanctions against the island. But he is rightly not blockading Cuba or closing US diplomatic offices in Havana.
Similarly, the White House should not acquiesce to provisions of the House of Representatives version of the bill that would allow Cuban-Americans to sue foreign companies that use private property seized by the Castro regime.
For those with a realistic understanding of who Fidel Castro is and what he represents, the shootdown is disturbing, but not surprising. The Cuban exiles' flights were unwise. But the proper way to intercept an unarmed aircraft is to escort it out of a country's airspace or force it to land, arrest the pilot, and perhaps confiscate the aircraft. Cuba's action is completely outside the norms of international law and the UN Security Council was right to deplore it.