The Khmer Rouge guerrillas are no longer struggling to survive. Instead, as the dry season begins here, the question has become: Can the Khmer Rouge consolidate recent tactical gains made against the Vietnamese in their small corner of Kampuchea?
''We are no longer threatened with extinction,'' says Khmer Rouge spokesman Ieng Sary, interviewed at his jungle camp near here at Phnom Malai.
That itself is quite an achievement. Five years ago, 100,000 Vietnamese troops blitzed across Kampuchea, overthrowing the then prime minister, Pol Pot, whose fanatical three-year reign of terror had left hundreds of thousands of Kampucheans dead. The Vietnamese installed a client government in Phnom Penh and expected to finish off the remnants of Pol Pot's Khmer Rouge army in short order.
Yet today the Khmer Rouge forces appear remarkably relaxed. As the visitor enters this military encampment that serves as headquarters for Division 450 of the Khmer Rouge guerrilla army, he finds the soldiers enjoying a raucous game of volleyball while Vietnamese artillery rounds boom in the background. The guerrillas have carved out a strong enough position for themselves to indulge in an occasional respite from a war noted for its ferocity and brutality on both sides.
The quick military victory in Kampuchea envisioned by Hanoi has failed to materialize for a several reasons.
The Kampuchean government and army installed by the Vietnamese under Heng Samrin have proven unable to coalesce as credible nationalist forces. This has made it necessary for more than 150,000 Vietnamese soldiers to remain as an occupation army.
The Vietnamese have found this position less and less to their liking as costs and casualties have mounted. Their presence, moreover, continues to incur hostility from the keenly nationalistic Kampucheans - even among some of those who at first welcomed Hanoi's army as liberators from the terror of Pol Pot.
The Kampuchean resistance has also been reinforced by a number of geopolitical factors. China, which sees the Kampucheans as a potent ally against Soviet-Vietnamese influence in Asia, has kept up a massive supply of arms to the Khmer Rouge resistance throughout the last five years.
Thailand also feels threatened by an expansionistic Vietnam. So it has quietly allowed its border area to be used as a transit ground for equipment bound for the guerrillas and as a sanctuary for Kampuchean refugees when the fighting periodically intensifies.
The other members of the Association of Southeast Asian Nations (ASEAN) as well as Japan, the United States, and other Western countries have also maintained strong political and economic pressure on Vietnam to withdraw from Kampuchea.
Perhaps Vietnam's biggest miscalculation was in un-derestimating the loyalty, discipline, and fighting power that Pol Pot would continue to command once out of Phnom Penh and back in the jungles and mountains of Kampuchea where his zealous peasant army was first formed in the 1960s.
The Khmer Rouge removed Pol Pot from the political scene four years ago because of his odious international reputation. He was replaced as titular leader by Khieu Samphan. But Pol Pot remains commander in chief of the Khmer Rouge army. He is reported to be personally leading the resistance from roving headquarters in the north, northwest, and far west of Kampuchea.
Despite his ignominious past as a political leader, Pol Pot and the other veteran military men of the Khmer Rouge are apparently highly capable battlefield commanders. His soldiers are not the ones who suffered in the 1975- 78 period, when, according to the present government in Phnom Penh, 3.3 million Khmers were killed or died under Pol Pot's rule. The soldiers are mostly peasants who have grown up in the guerrilla culture of the Khmer Rouge and maintain a fierce and impassioned loyalty to the anti-Vietnamese cause.
Finally, the Vietnamese counted heavily on a continuing disruptive rivalry between the Khmer Rouge and the other two principal resistance factions. These are headed by Kampuchea's former monarch, Prince Samdech Norodom Sihanouk, and by a former Kampuchean prime minister, Son Sann.
The three groups clashed frequently with one another between 1979 and 1981. But in mid-1982, encouraged by China and ASEAN, they agreed to the formation of an anti-Vietnamese Coalition Government for Democratic Kampuchea, with Prince Sihanouk presiding and Son Sann and Khieu Samphan as his deputies.
Although the unity of the three groups remains chiefly cosmetic - as in a joint visit by the three leaders to Peking in December - Khmer Rouge military sources report that the level of intra-resistance skirmishing has been reduced to practically nil. This has enabled them to concentrate exclusively on fighting the Vietnamese instead of one another.
''In the last rainy season we successively liberated all the Vietnamese positions around Nimit,'' says So Pin, who commands 3,500 soldiers and support personnel in the 450 Division. ''Now we are able to encircle Nimit, which is the last big Vietnamese position in this area. We are not strong enough to storm their garrison, but they are not strong enough to break our encirclement.''
If the Vietnamese forces at Nimit can be further weakened through hit-and-run assaults during the current dry season, So Pin says, Khmer Rouge ability to attack Highway 5 south of Nimit will be greatly strengthened.
The Thai press has speculated that Vietnam will mount the biggest dry season offensive of the war in the coming two months. Khmer Rouge sources, however, say they have not yet seen the kind of preparations that usually precede such a thrust.
''It may be simply because the rains were so heavy this year that they have gotten a late start,'' observed Ieng Sary, the Khmer Rouge spokesman and a former deputy premier under Pol Pot. This past season the region has suffered its worst flooding in 40 years.
''We are not so optimistic as to think they will do nothing, but we don't think they will do very much,'' he added. ''They would have to commit another two to three divisions against us to stage a major offensive in the northwest. There is no sign they are prepared to do that.''
The changes in the military situation in Khmer Rouge-controlled areas over the last several years are substantial. The O Sralao Bridge, for example, which was the scene of fierce fighting in 1981 when the Vietnamese controlled it, is today under Khmer Rouge command. A visit to the area shows that the Khmer Rouge are building a dam on the river for irrigation of nearby areas where they hope to plant rice this year.
Once reliant exclusively on hacking their way through the cover of the jungle , the Khmer Rouge soldiers now travel openly along significant stretches of established roads like Route 502, which parallels the Thai border from Kampuchea's westernmost point until it meets National Highway 5. For more than two years the Khmer Rouge have attacked key points along the highway.
Highway 5 has become perhaps the most strategic road of the entire war. It links the Vietnamese forces based in Phnom Penh with all of western Kampuchea, including the western shore of Tonle Sap - the great lake in Kampuchea's heartland with its abundant fish and fertile rice plains that surround it - as well as major population centers in Pursat, Battambang, and Sisophon. In the last rainy season, Khmer Rouge guerrillas reportedly rendered large parts of the northern stretches of Highway 5 impassable and established effective control of a few strips of it.
A rudimentary telephone and telegraph network now links the various Khmer Rouge military bases, which were once dependent on runners for communication.
A patchwork of villages adjacent to military bases has developed where the wives and children of soldiers live. The Khmer Rouge forces look after food, clothing, and housing for their soldiers' dependents. Near the Bantaey Ti Pi base, for example, about 3,000 family members are housed in a civilian village that appeared affluent by standards of war-torn Kampuchea: plentiful rice, pigs, chickens, and vegetables.
Roeun Mot, a woman whose husband had been at the front for a month, observed, ''The family members here have nothing to worry about when the men go to the front. Everything we need is provided.''
Such incentives in a country still haunted by the specter of mass starvation have undoubtedly augmented the number of returning refugees who want to join the Khmer Rouge forces.
The ''new political policy'' of the Khmer Rouge has also helped attract a small number of brave returnees who are willing to take a chance that the change toward moderation is genuine. Under the new policy, much of the Khmer Rouge's past fanaticism is consigned to the category of ''political mistakes,'' communism is rejected as their guiding ideology, and a liberal policy of national unity is projected for the future.
According to Western diplomatic sources in Bangkok, Thailand, the Khmer Rouge armed forces are indeed growing for the first time. After five years of attrition, their numbers had dropped as low as 25,000, according to some analysts. The consensus among Kampuchea-watchers in Bangkok is that Khmer Rouge forces now number at least 35,000.
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