After returning to Cambodia in 1953, Pol Pot threw himself into party work first in Kampong Cham Province (Kompong Cham) and then in Phnom Penh under Tou Samouth's "urban committee." His comrades, Ieng Sary and Hou Yuon, became teachers at a new private high school, the Lycée Kambuboth, which Hou Yuon helped to establish. Khieu Samphan returned from Paris in 1959, taught as a member of the law faculty of the University of Phnom Penh, and started a left-wing, French-language publication, L'Observateur. The paper soon acquired a reputation in Phnom Penh's small academic circle. The following year, the government closed the paper, and Sihanouk's police publicly humiliated Khieu by undressing and photographing him in public--as Shawcross notes, "not the sort of humiliation that men forgive or forget." Yet the experience did not prevent Khieu from advocating cooperation with Sihanouk in order to promote a united front against United States activities in South Vietnam. As mentioned, Khieu Samphan, Hou Yuon, and Hu Nim tried to "work through the system" by joining the Sangkum and by accepting posts in the prince's government. Hardliners like Pol Pot, Ieng Sary, and Son Sen advocated resistance.

In late September, 1960, twenty-one leaders of the KPRP held a secret congress in a vacant room of the Phnom Penh railroad station. This pivotal event remains shrouded in mystery because its outcome has become an object of contention (and considerable historical rewriting) between pro-Vietnamese and anti-Vietnamese Khmer communist factions. The question of cooperation with, or resistance to, Sihanouk was thoroughly discussed. Tou Samouth, who advocated a policy of cooperation, was elected general secretary of the KPRP that was renamed the Workers' Party of Kampuchea (WPK--see Appendix B). His ally, Nuon Chea (also known as Long Reth), became deputy general secretary; however, Pol Pot and Ieng Sary were named to the Political Bureau to occupy the third and the fifth highest positions in the renamed party's hierarchy. The name change is significant. By calling itself a workers' party, the Cambodian movement claimed equal status with the Vietnam Workers' Party. The pro-Vietnamese regime of the People's Republic of Kampuchea (PRK-- see Appendix B) implied in the 1980s that the September 1960 meeting was nothing more than the second congress of the KPRP.

On July 20, 1962, Tou Samouth disappeared. He may have been the victim of Sihanouk's police, but some observers suggest that Pol Pot, who had built up a strong faction within the party, had him eliminated. In February 1963, at the WPK's second congress, Pol Pot was chosen to succeed Tou Samouth as the party's general secretary. Tou's allies, Nuon Chea and Keo Meas, were removed from the Central Committee and replaced by Son Sen and Vorn Vet. From then on, Pol Pot and loyal comrades from his Paris student days controlled the party center, edging out older veterans whom they considered excessively pro-Vietnamese.

In July 1963, Pol Pot and most of the central committee left Phnom Penh to establish an insurgent base in Rotanokiri (Ratanakiri) Province in the northeast. This is a region inhabited by tribal minorities, the Khmer Loeu (see Appendix B), whose rough treatment (including resettlement and forced assimilation) at the hands of the central government made them willing recruits for a guerrilla struggle. In 1965 Pol Pot made a visit of several months duration to North Vietnam and China. He probably received some training in China, which must have enhanced his prestige when he returned to the WPK's liberated areas. Despite friendly relations between Sihanouk and the Chinese, the latter kept Pol Pot's visit a secret from Sihanouk. In September 1966, the party changed its name a second time, to the Kampuchean (or Khmer) Communist Party (KCP--see Appendix B). Adopting the label "communist" suggested that the Cambodian movement was more advanced than Vietnam's (which was merely a "workers' party"), and was on the same level as China's.

Data as of December 1987