During a meeting with one of our agents in a safe house [in Hong Kong], we obtained information that told of huge Chinese arms shipments going through Cambodia and into South Vietnam to help the Viet Cong. We also learned that the head of Cambodia’s armed forces, Lieutenant General Lon Nol, was overseeing the shipments and taking a cut of the arms for the benefit of himself and his own army. In the late 1960s at the time when the arms shipments were at their highest levels, Lon Nol was a favorite of Peking. He was said to have a big picture of Chairman Mao over his desk in Phnom Penh. But we knew that Lon Nol was also a Cambodian patriot. Like their Laotian neighbors to the north, the Cambodians were strongly against Vietnam, whom they saw as the regional bully. Lon Nol was particularly upset that, in their effort to prosecute the war in South Vietnam, the North Vietnamese Army had occupied areas of eastern Cambodia. Our source told us that when the Cambodian Defense Minister traveled to Peking in the fall of 1969, he made a strong appeal to the Chinese to help him get the Vietnamese out of Cambodia. Lon Nol said he was willing to help supply the Viet Cong, but he insisted that Vietnamese troops belonged in Vietnam, not in Cambodia. The Chinese demurred. In Peking’s eyes the North Vietnamese were fighting a war of national liberation against the American imperialists, and it was China’s socialist duty and in the country’s own interest to support its communist brethren.
The tiff between Lon Nol and Peking turned out to pay off, at least temporarily, for the U.S. Just six months after visiting Peking, in March 1970 General Lon Nol, in part bitter and disappointed at being rebuffed by the Chinese, staged a coup along with First Deputy Premier Sisowath Sirik Matak against Prime Minister Sihanouk and seized power. From Hong Kong we reported to Washington the first signs of a coup when we picked up information that commercial flights from Hong Kong to Phnom Penh were being canceled because the Phnom Penh Airport was closed. Once in power, Lon Nol turned from a supplier to the communist cause in Southeast Asia into an adversary. In an attempt to hinder the Vietnamese communists in their fight to take over South Vietnam, he tried to cut weapons supply lines through Cambodia to Vietnam. Then he cooperated with the U.S. military in its incursion into Cambodia in the spring of 1970, which hurt the North Vietnamese but did not drive them out. In this backdrop to the war next door in Vietnam, thanks in part to the reporting from our source, the U.S. briefly gained the upper hand at China’s expense.