THAI AIRWAYS, flashing orchids, beckons the traveler on "a flight of graciousness." For a certain class of traveler approaching Thailand by sea, however, passage is a flight of horror. We refer to Vietnamese boat people, who continue to be subjected to the most unimaginable cruelties by Thai "pirates" operating in the Gulf of Thailand. Despite practical assistance (spotter planes, patrol boats, police funds) by the United States and other nations, the Thais seem unable to take the problem in hand.

A dozen reasons are cited to explain why the Thais have not gone beyond minimal surveillance and prosecution: the sea is vast, as many as 60,000 Thai fishing boats operate in the gulf, and so on. But let us look a little closer. The term "pirates" is utterly misleading, suggesting as it does to Western ears rogues, even swashbucklers, people without a country who are somehow flourishing beyond the law. These criminals, however, are simply ordinary Thai fishermen who are free-lancing and moonlighting as "pirates," having found an easy mark: stateless Vietnamese who have no government to speak for them. Do you imagine that the same Thai fishermen would be plundering, raping and murdering if the victims were Thais? They would know that upon returning to home and shore they would likely face an accounting, and they would tailor their behavior accordingly.

The problem is not the vastness of the sea but, it seems, the narrowness of the Thais. There is no denying that they have borne the principal burden of the Indochina refugee exodus, being often the country of "first asylum," and they still deserve gratitude and practical help for this role. But a growing hesitation to accommodate new refugees is evident, and it is hard to believe that some Thai officials do not see the so-called piracy--which is just a kind of predatory crime--as a cruel but nonetheless somewhat effective way to reduce the flow.

The U.S. government has various fish to fry in Thailand and apparently does not wish to make too much noise over refugees. But the Thais are American allies, and the victims are people for whom the United States has a measure of continuing moral responsibility. It is tragic enough that the Hanoi government makes life at home so unbearable that numbers of Vietnamese continue to prefer the now- familiar risks of fleeing by sea. Thailand can surely diminish the terrors of the boat people's ordeal.