Meanwhile, events were moving rapidly in Phnom Penh. In January 1970 Sihanouk left for his annual rest cure in France, unintentionally beginning a life of exile that was to last several years. Before leaving, he had been psychologically bruised by encounters with the hostile National Assembly. Partly to regain control and partly because he was genuinely frightened of Vietnamese incursions, he asked Lon Nol to increase pressure on Communist forces. While the prince was overseas, supplies to the Vietnamese forces in Cambodia were cut off, and government-sponsored riots damaged the diplomatic missions of Vietnamese Communists in Phnom Penh.38

On March 19, 1970, Sihanouk was voted out of office by the National Assembly. The coup d‘état was bloodless, although later in the month pro-Sihanouk demonstrations were brutally suppressed in several provinces. Two days before the coup, Lon Nol had ordered all Vietnamese forces to leave Cambodia within forty-eight hours. Not surprisingly, there was no response, but the quixotic command reflected widespread popular opposition to the Vietnamese. When the coup took place, the prince was in Moscow on his way home. Half stunned and half enraged, he proceeded as planned on the next leg of his voyage to Beijing.

The coup seems to have taken Saloth Sar and his patrons by surprise, although the Livre noir contends that he foresaw the coup six months before it occurred and Nuon Chea, in his 1997 party history, claims that policy since 1967 had been based on the likelihood of a right-wing coup. If Sar indeed foresaw the coup, his long absence from Cambodia in 1969-1970 is difficult to explain. The Livre noir also states that in early 1970 Sar had traveled to Beijing from Hanoi “for discussions” and was thus in the Chinese capital when Sihanouk arrived on March 19. It seems more likely that Sar came from Hanoi with the Vietnamese premier, Pham Van Dong, who had been hastily summoned by the Chinese and arrived in Beijing two days after Sihanouk got there.39

The Livre noir claims that Saloth Sar persuaded the Chinese prime minister, Zhou Enlai, that Sihanouk should adopt an offensive posture toward Lon Nol and, by implication, toward the United States, reinstating an anti-American policy he had abandoned a year before. According to other sources, Pham Van Dong encouraged the prince to resist, promising to return him to power “within forty-eight hours.” Thus Sar’s advice to Zhou, if it was ever given, was identical to the advice offered to Sihanouk by Pham Van Dong. To keep Sihanouk happy and to protect the Cambodian Communists as a long-term asset, the Chinese and Vietnamese concealed Sar’s presence in Beijing from the prince, who did not identify him as the leader of the party for several years.