Profile of Kampuchean resistance

The anti-Vietnamese Coalition Government of Democratic Kampuchea is now one year old. Its first anniversary has confounded some critics who said it would not last six months, and confirmed others who suspected it would be too shaky to be effective. The latest shock came earlier in June when Prince Norodom Sihanouk threatened again to resign the coalition's presidency.

Below, a profile of the coalition:

Origins. The Khmer leaders, which China and the Association of Southeast Asian Nations (ASEAN, consisting of Thailand, Malaysia, Singapore, Indonesia, and the Philippines) have united against the Vietnamese, are reluctant allies. These are the titular Khmer Rouge leader Khieu Samphan, and two noncommunists, Prince Sihanouk and Son Sann.

All three know one another well. In the mid-1960s, Khieu Samphan and Son Sann were Cabinet ministers under the prince. When the Khmer Rouge came to power, Son Sann was in France. And after serving briefly as figurehead president for the Khmer Rouge, Prince Sihanouk was put under house arrest. The three men were reunited in Singapore in September 1981 at a publicly affable, privately stormy meeting. They agreed to discuss a coalition. Formation of the coalition took nine more months.

Members: Prince Sihanouk is president; Khieu Samphan is vice-president in charge of foreign affairs; Son Sann is prime minister. All three factions retain separate identities. They maintain their own armies, raise their own funds. If the coalition breaks up, the UN seat reverts to the Khmer Rouge.

Forces. Although politically discredited, the Khmer Rouge remain the strongest military force in the coalition. Troops estimates vary from 50,000 by their closest allies, the Chinese, to between 22,000 to 30,000 by Western sources in Bangkok.

The Khmer Rouge have tried to improve their image. Pol Pot, Khmer Rouge leader during the years of massacre and starvation of Democratic Kampuchea (1975 -79), stays out of sight. Observers agree, however, that he still calls the shots. Khmer Rouge behavior toward peasants under their control has in some places reportedly improved. But this has not prevented a steady erosion of Khmer Rouge support and fighters.

The Khmer People's National Liberation Front (KPNLF), headed by Son Sann, is the larger of the two noncommunist factions. Many of Son Sann's followers are Khmer Krom (ethnic Khmers from southern Vietnam), many of whom spent much of the 1960s trying to overthrow Sihanouk. Estimates of military forces range from 9, 000 to 14,000, capable, Western sources say, of penetrating 30 to 40 kilometers inside Kampuchea.

Sihanoukist forces are tiny and disorganized. Sympathetic Western sources say the prince has about 1,400 fighters.

Aid. The coalition receives arms and ammunition from China and Singapore. The latest Chinese shipment, reportedly including antitank weapons, arrived in March. ASEAN sources say that Malaysia offers training and Thailand some transport and communications equipment. Humanitarian aid comes from a number of countries, including Japan, West Germany, and Australia. Khmer Rouge aid in particular comes exclusively from China - ''probably a blank check,'' said a veteran observer.