The Vietnamese control most of Cambodia. But they do not control the largest Cambodian city. That is not in Cambodia at all, but in Thailand. Its name is Kao-I-Dung, and it is run by a young British journalist working for the United Nations High Commissioner for Refugees (UNHCR.)

This is a time of runaway inflation in the refugee business, with about 12 million refugees scattered around the globe. UNHCR deals with a population bigger than that of many nations.

Refugees are citizens of a nether world, a fourth world that in international terms is an unwanted world -- particularly in countries of the more familiar Third World, to which most of today's refugees initially flee.

In the West, refugees arouse compassion -- for a time -- and some of them are given practical help -- for a time. Often, though, Western attention moves on, before any real solution has been found for them. The country in which they have sought "first asylum" is forced to give them a permanent home. As a result, the principle of first asylum is being eroded. It is just too expensive.

The story of the tensions between UNHCR and the Thai government, which has not signed the U.N. Covenant of the Treatment of Refugees, is certainly dramatic, but it is not unique. It helps illustrate the difficulties faced by a sometimes inexperienced international agency when dealing with a government that is, at best, a reluctant host to the casualties of a neighboring disaster.

At the same time, the precarious position of the Cambodian refugees -- at least 150,000 in makeshift camps along the Thai border as well as another 150,000 in UNHCR camps inside Thailand -- presents a serious long-term political problem not only for Thailand but also for the world. And American and other officials in Bangkok are terrified that if the West does not immediately find what UNHCR calls a "durable solution" for them, the Thais will act unilaterally and drive them all back by force -- with terrible loss of life.

Twice last year, in fact, Thai authorities organized forcible mass repatriations of Cambodian refugees to their native battleground to face almost certain death.

Now fears for the refugees are being expressed with greater urgency every week by Western officials in Bangkok. The replacement of Prime Minister Kriangsak Chamanan last month by a government thought to be more hostile to the refugees is one reason. Another is the approach of the rainy season. Floods would provide the Thai government with a convenient excuse for clearing the refugee camps, none of which is well enough constructed to withstand the rains.

Some sort of crisis is imminent, insist State Department officials.

Lionel Rosenblatt, head of the U.S. Embassy's Kampuchea Emergency Group, is anxiously trying to find countries to take as many refugees as possible -- now. It is a measure of his concern that he is even prepared to consider a scheme that strikes some relief officials as distasteful -- the proposal of an American voluntary agency to resettle Cambodian refugees in Jonestown, Guyana.

Rosenblatt even has a memorandum identifying those areas of the world's oceans that are shallow enough to build artificial islands. The islands could then be used as havens for refugees. Rosenblatt also has considered the idea of creating self-supporting refugee communities on exisiting uninhabited islands.

Denial of refuge has been outlawed by the U.N. Covenant on Refugees. Yet governments have duties to their own citizens as well, and they often see these as conflicting with the claims of masses of homeless, indigent foreigners. All too often refugees threaten to become not just an economic burden but also a source of both internal and external political conflict.

One of UNHCR's primary responsibilities is to protect refugees from forced repatriation. As the Red Cross and UNICEF have tried to do on food aid to Cambodia UNHCR's international civil servants have chosen to refuse to publicize open Thai violations of this principle, in favor of trying to work quietly to get the Thais to change their attitudes about the Cambodian refugees.

In the process, lives have been lost. But international officials have argued that long-term interests have been served.

Refugees began to flee Vietnam, Laos and Cambodia as soon as the communists won victory in 1975. (Until then the war had created millions of refugees within those countries.) Between 1975 and 1979 Thailand, which borders both Laos and Cambodia, accepted about 150,000 refugees from those countries on the grounds that they were fleeing communist regimes. Immediately after the January 1979 Vietnamese invasion of Cambodia, thousands more refugees headed for Thailand.

The Thai government, however, announced that these refugees were different.

Many of them, government officials asserted, were communists fleeing an internecine dispute between two communist factions, and therefore could not be allowed to stay. Those who did enter the country in the first few weeks of 1979 were put under military control rather than, as before, under the Interior Ministry. They were not given refugee status; instead they were labeled "illegal immigrants."

UNHCR offered to help care for the new arrivals. The Thai government refused assistance. Refugees came in small numbers between January and April. Some were allowed to stay; many were pushed back into Cambodia by the Thai military.

In April, the Vietnamese mounted a new offensive against Khmer Rouge strongholds in Western Cambodia. This attack pushed about 40,000 people into Thailand. Again UNHCR offered its services; again the Thais refused. Thai officials made clear that they were unwilling to accept any "strings on the way they dealt with "illegal immigrants." They apparently felt that the very presence of UNHCR would raise the Cambodians' status.

On April 12, 1979, a group of about 1,700 "illegal immigrants" at the border town of Aranyaprathet -- many of whom had relatives in Thai camps for pre-1979 "refugees" -- were loaded by the Thai military onto buses. They were told they were being taken to another, better camp site. It was not true. They were forced at gunpoint back over the border into Cambodia where they faced death from either starvation or the continued fighting.

UNHCR reaction was muted. No protest was made, except by the field officer for the Aranyaprathet area, David Taylor. When the Thais tried to force more refugees back over the border a few days later, Taylor rushed to the scene and dramatically barred the way. He save one group.

Taylor's effort was written up critically -- in the local press. Thai officials were furious at this "intervention in Thailand's internal affairs." They demanded Taylor's withdrawal from the border. His life was threatened. t

Taylor was withdrawn, and UNHCR sent no one to replace him for several months. For much of 1979, the UNHCR office in Bangkok was also without a Regional Protection Officer, the post with overall responsibility for preventing forced repatriation. So neither on the border nor in Bangkok did UNHCR have officials dealing full time with the repatriation crisis.

At that time the official policy of the Bangkok office of the UNHCR was not to antagonize the Thais lest they treat the Cambodians even worse. Many junior UNHCR officials were strongly opposed to this seeming acquiescence in forcible repatriation. They felt it would only encourage the Thais, and they seem to have been right.

In May, U.N. Secretary General Kurt Waldheim visited Aranyaprathet. Cambodians there protested to him about the forcible repatriation of their kin, and he insisted on visiting 4,000 newly arrived "illegal immigrants."

Waldheim took the issue seriously and raised it with Kriangsak, then Prime Minister. He emphasized that as far as UNHCR was concerned these were genuine refugees who must not be forced back into Cambodia; UNHCR would do all it could to help. The Prime Minister made no commitment.

The government was obviously not impressed. The next repatriation was far worse.

In June the Thai military gathered some 40,000 refugees who were camped along the border (including the 4,000 whom Waldheim had visited), bused them away and then forced them, at night and at gunpoint, down a steep cliff, across a minefield and back into Cambodia. There was no water there. Many who tried to move forward were killed by mines. Many who tried to move back were shot by Thai soliders. Thousands died.

The International Committee of the Red Cross (ICRC) issued a strong protest against the action. Once again UNHCR failed to do so. The head of the Bangkok office, Leslie Goodyear, argued that to criticize the government might provoke harsher measures. Some of the so-called "young Turks" in the office wrote to Geneva headquarters to complain.

Obviously the decision as to when forceful protests are required and when discretion is more valiant is difficult. Goodyear was not alone in believing caution to be the best course. The voluntary agencies in Thailand were also divided.

After the April repatriation the main coordinating group of the voluntary agencies protested to the Minister of the Interior. The effect was, however, badly undercut when World Vision, one of the largest Christian agencies trying to work with Cambodians, wrote a letter to the Ministry of the Interior disassociating itself totally from the protest.

The forcible repatriation issue was one that Western embassies also found difficult to address. Few, if any, seem to have made any effective protest.

The U.S. Embassy, however, was able to rescue about 2,000 of the refugees involved. The U.S. Ambassador, Morton Abramowitz, had throughout the crisis been one of the most effective and energetic spokesmen for the Cambodians.

At this time Prime Minister Kriangsak told diplomats that the policy of repatriation would be stopped only if the world paid attention to Thailand's predicament at the forthcoming Geneva Conference on Indochinese refugees in July.

In the event, Thailand's problems were practically ignored, as was Cambodia itself, at Geneva. All through last summer attention was fixed only on the Vietnamese boat people. But at Geneva the United States raised its monthly quota of Indochinese refugees to 14,000 and promised that a large number would be Cambodians from Thailand. The Thai government seemed appeased.

By early September it was clear that conditions in western Cambodia were becoming more desperate than ever and that a massive flood of diseased, exhausted, starving people -- far greater than any before -- was about to swamp the border.

Until now voluntary agencies, particularly Catholic Relief Services, had been putting food across the border to feed Cambodians. Now the Thai government encouraged the international organizations to become more closely involved. This was not popular with some voluntary agencies, which felt they were doing an adequate job and that the international organizations were too steeped in diplomatic problems to be effective.

On Sept. 18, the Thai government's chief refugee coordinator, Air Marshal Sithi Sawetsila, called a meeting of 11 Western embassies and several international organizations. ICRC, despite its voluble protest over the repatriation of the 40,000, was invited. UNHCR, despite its lack of protest, was not. Sithi asked for help in coping with an imminent influx of 20,000 Cambodians, but little was promised.

Then Martin Barber and Pierre Jambor, two senior UNHCR officials in Bangkok, persuaded Geneva that it was essential for UNHCR to act. From now on UNHCR performance was much more effective. The agency went to Sithi and offered $500,000 as a first contribution toward meeting the crisis. The gift was accepted at once, with considerable ceremony.

By now the attention of the Western press was finally directed toward Thailand. Pictures of starving Cambodian mothers and children replaced those of boat people. Conscious of world attention, and at the urging of the U.S. Embassy, Thailand now adopted a new four-part policy:

UNICEF and ICRC were to be helped in running an assistance program to Phnom Penh from Bangkok.

These organizations must also, however, push food across the border in hopes that it would discourage at least some starving Cambodians from fleeing to Thailand.

Holding centers for "illegal immigrants" who crossed the border would be established.

Resettlement to third countries must be encouraged.

By mid-October there were at least 100,000 starving Cambodians on or along the Thai-Cambodian border. On Oct. 18 Kriangsak visited the area and, obviously moved by the misery he saw, expanded the government's new policy. Thailand would now have an "open door" and would allow entry to all Cambodians who wished to come. They could either stay along the border, where they would be fed or be moved into "holding centers."

From Washington, first Richard Holbrooke, assistant secretary of state for East Asia and the Pacific, and then Rosalynn Carter flew out to underline U.S. support of this new policy.

Three days later March Malloch-Brown, the English journalist who was David Taylor's eventual successor as UNHCR field officer for the Aranyaprathet area, was dispatched from Bangkok. "I had $1,000 in my bags and I was told to see if there was anything I could do to help the Thais." He was taken by Thai officials to an empty, monsoon-sodden field near a town called Sakeo, and told to build a camp.

Within five days, 30,000 refugees had been bused there from the border. Brown built a camp around them.

Conditions at first were dreadful. Many refugees -- who were mostly Khmer Rouge partisans or civilians under Khmer Rouge control -- died en route in the buses. About 40 others died every day for the first few weeks from cerebral malaria, malnutrition, or pneumonia. Housing initially was nonexistent; sanitation worse. Everything was flooded.

UNHCR is an administrative, rather than operational agency, and it had to rely on volunteers and voluntary agencies for staff. Expanding to meet the demand was not easy. It was not until December that Brown was able to employ a full-time engineer; until then he had to rely on a U.S. Embassy aid officer, who was fortunately very efficient.

The speed with which UNHCR created a reasonable township at Sakeo clearly impressed the Thai authorities. On Oct. 30, Sithi asked the agency to coordinate plans for receiving up to 300,000 "illegal immigrants." Another site was found. This was Kao-I-Dung.

Drawing on the experience of Sakeo, Brown helped build a dry-season camp there, and through December and early January, about 112,000 Cambodians were moved in from border settlements, where at least another 150,000 remain.

The Thais now have officially closed Kao-I-Dung to new arrivals, but there is a fairly constant, surreptitious nighttime movement between the camp and the border, as the largest concentration of Cambodians in the world await decisions about their futures with obvious anxiety.

The chief fears are over Thai intentions, and over UNHCR's ability -- and willingness -- to protect them. The Thai and the Khmer people have never held each other in high regard, and giving sanctuary to the refugees wins a government no support in Thailand. Indeed, the "open door" policy contributed to the fall of the Kriangsak government last month.

In Bangkok, senior Thai officials privately speak of the refugees with contempt, even anger. Newspaper editorials demand their expulsion. Very little had been done by the Thais to prepare the camps for the monsoon. This adds to refugee fears.

An accident at Kao-I-Dung in January reveals Thai-Cambodian dislike. The Thai Red Cross decided to move almost 200 orphans to a special camp run by the Queen of Thailand. With the connivance of UNHCR and Catholic Relief Service officials the Cambodians emptied the orphanages, hiding the children among families. When the Thai Red Cross officials turned up with buses and armed soliders, no children could be found. They were not amused and threatened to return.

At the moment, UNHCR has been discouraging the growth of a "resettlement mentality" in the camps. Officials argue that everything should be done to encourage their voluntary return to Cambodia. Cambodia will need them, and no other country can take many of them. To this end, Zia Rizvi, the energetic new UNHCR regional coordinator, visited Phnom Pehn last month to discuss the issue with the Heng Samrin government.

When news of Rizvi's mission was broadcast over the Voice of America, there was instant panic in Kao-I-dung. Hunger strikes, even suicides were threatened. Almost no one wished to return under either the Vietnamese or the Khmer Rouge.

In an interview with the Washington Post a few days before his surprise resignation last month, Prime Minister Kriangsak gave a categorical assurance that Thailand would not repatriate any of the Cambodians against their will.

The attitute of the new government to the refugees is not yet really clear. But just yesterday one new minister made very threatening remarks about them.

Other aspects of Thai policy to Cambodia remain constant and are incompatible -- at last in the short term -- with creating the sort of stability that alone could make it attractive for the "illegal immigrants" to return to their homeland.

For one thing, the Thai government is directly aiding the Khmer Rouge and other groups to resist the Vietnamese occupation. That is not Thai policy alone. It is shared by all the ASEAN nations, by China and -- especially since the Soviet invasion of Afghanistan -- by many Western countries as well, in particular the United States.