Buildup on the Border

Confronted by persistent allied military pressure, North Vietnamese infiltrators are finding their old southbound routes to be increasingly hazardous traveling. The DMZ and the South China Sea coast have been virtually sealed off, and the Ho Chi Minh Trail's Laotian branch is being steadily pounded from the air. That leaves only Cambodia as a relatively bomb-free route into South Viet Nam. This kind of end run is hardly new to the Communists, who have often used Prince Norodom Sihanouk's neutral kingdom as a gateway and a sanctuary. But the rising intensity of the war is causing them to use Cambodia more and more as a launching pad and supply depot.

The Communists have dotted Cambodia's 600-mile frontier along South Viet Nam with dozens of jungle encampments, of which at least five are classified by U.S. intelligence as major bases (see map). The network, which stretches from the marshlands of the Mekong Delta into the bloodied hills of the Central Highlands, is believed to support six regiments of North Vietnamese regulars as well as innumerable Viet Cong guerrillas--a total of up to 20,000 men who are kept busy raiding and reconnoitering along the border. A key base is tucked away in Cambodia's "Parrot's Beak," just 40 miles west of Saigon, which also harbors one of the several jungle hospitals established by the Communists.

Sihanouk Trail. According to the detailed picture that emerges from box-loads of intelligence reports in Saigon, the camps are used as training centers, supply storehouses and marshaling points for such large-scale Communist operations as last month's attacks on Loc Ninh, which lies directly across from two major bases, and the fighting at Dak To, which faces another base at the intersection with Laos.

Most of the heavy military equipment for the Communist troops continues to come down the pipeline from the North through Laos, but the Communists manage to fill much of their food and clothing needs within Cambodia itself. Under a procurement system involving the Chinese embassy in Pnompenh, the Communists buy up to 100,000 tons of Cambodian rice a year. Until the Cambodian army cut itself into the lucrative trade recently in order to raise money for Sihanouk's pet welfare programs, it was handled almost exclusively by Cambodia's colony of Chinese merchants.

Delicate Balancing. Other food, medicines and soft goods arrive by ship from North Viet Nam and China at Sihanoukville, Cambodia's outlet on the Gulf of Thailand. They are then trucked over the U.S.-built Friendship Highway to Pnompenh and sent to the border bases along routes that the American military has named the Sihanouk Trail. Occasionally, V.C. guerrillas buy surplus Chinese small arms from local Cambodian commanders, but this is strictly local enterprise by Sihanouk's low-paid officers.

On his recent visit to the U.S., General William Westmoreland expressed concern and anger at this enemy build-up just beyond the reach of his troops. There has even been some talk among the military of a Cuba-type "quarantine" of Sihanoukville. But the idea hardly pleases U.S. diplomats. However annoying they find Sihanouk's warm embrace of Hanoi's cause, they recognize that he is engaged in a delicate balancing act to keep his country out of the Communist grip. Even if he fully appreciated the magnitude of the infiltration--as he does not seem to--and were determined to kick the Communists out, his 30,000-man army could hardly cope with the North Vietnamese regulars.

U.S. officials hope that Sihanouk's neutrality may gradually become a little less Red-tinged. Occasionally they are encouraged by such actions as Sihanouk's recent forceful response to Peking's propagandizing in Cambodia; he closed down Red-lining newspapers and threatened to recall his ambassador. But Sihanouk has a way of dissipating good will quickly. Recently he has been mixing particularly virulent attacks on the U.S. ("neocolonialist aggressor") with denials that the Communists are using Cambodia as a sanctuary. Last week, angered by the discovery of a Communist camp site inside Cambodia by three American newsmen (TIME, Nov. 24), Sihanouk declared that henceforth his borders would be sealed to all U.S. journalists.

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