A CENTRAL question in the debate on American policy toward the Soviet Union is whether the United States should withhold from selling certain kinds of products in order to exert some influence on Soviet policy - especially human-rights issues. Some American businessmen have complained that our restrictive policy on certain high-technology products is futile, since Russia can buy most such products elsewhere. But there is another kind of Amercian product that cannot be bought elsewhere. It is, moreover, a product notoriously in demand throughout the eastern bloc. I am referring, of course, to Levis, the world-famous denim pants made by Levi Strauss & Co.

The significance of Levis as a potential instrument of foreign policy becomes apparent if we consider the recent sale of almost 800,000 pairs to East Germany. Most East European countries spend their limited supplies of hard currency on basic industrial products, not such trivial consumer items. Why, then, did the East German government pay $9 million for jeans? To head off major social unrest.

According to a New York Times report, East Germany had manufactured blue jeans of its own earlier this year, but the venture failed. East Germans wanted the real thing, not an inferior, state-produced imitation. The country was in turmoil, with widespread grumbling among young people and factory workers.Thus the threat of a revolt by the unfashionably clad rather than the starving masses forced a desperate East German government to request a large shipment of jeans, which it has proceeded to sell at a hefty 149 German marks a pair (nominally equivalent to $74), both buying off and ripping off its citizens. And Hungary now has an agreement with Levi Strauss & Co. to make the jeans in that country.

In trying to win the hearts and minds of people around the world, some Americans have said that we should vehemently proclaim the virtues of democracy. But Woodrow Wilson already tried that; and for those who style their socialism as democratic, just the possibility of a socialism without Gulags is more attractive than the actuality of a representative democracy that supports cold-hearted capitalism.

Instead of trying to persuade them that socialism is not a good thing, we should say: "You can have your socialism, but then you must live with the products of socialism." And who wants to do that? The chief benefits one gains fater becoming a Very Important Communist is being able to buy capitalist products. No one - not even a socialist intellectual - wants to buy the products of socialist countries, except perhaps Polish hams and Russian caviar. Everyone wants to buy Japanese or German or South Korean cars, television sets, tape recorders and record players. And American jeans. A foreign policy based on jeans might do better than one based on a "respect for human rights." Ask most of the world what it thinks of American values and it sneers; ask most of the world if it wants American jeans, and it cries "Yes!"