The history of the communist movement in Cambodia can be divided into six phases: the emergence of the Indochinese Communist Party (ICP --see Appendix B), whose members were almost exclusively Vietnamese, before World War II the ten-yearÍÍÍÍ struggle for independence from the French, when a separate Cambodian communist party, the Kampuchean (or Khmer) People's Revolutionary Party (KPRP--see Appendix B), was established under Vietnamese auspices the period following the Second Party Congress of the KPRP in 1960, when Saloth Sar (Pol Pot after 1976) and other future Khmer Rouge leaders gained control of its apparatus the revolutionary struggle from the initiation of the Khmer Rouge insurgency in 1967-68 to the fall of the Lon Nol government in April 1975 the Democratic Kampuchea regime, from April 1975 to January 1979 and the period following the Third Party Congress of the KPRP in January 1979, when Hanoi effectively assumed control over Cambodia's government and communist party.

Much of the movement's history has been shrouded in mystery, largely because successive purges, especially during the Democratic Kampuchea period, have left so few survivors to recount their experiences. One thing is evident, however, the tension between Khmer and Vietnamese was a major theme in the movement's development. In the three decades between the end of World War II and the Khmer Rouge victory, the appeal of communism to Westerneducated intellectuals (and to a lesser extent its more inchoate attraction for poor peasants) was tempered by the apprehension that the much stronger Vietnamese movement was using communism as an ideological rationale for dominating the Khmer. The analogy between the Vietnamese communists and the Nguyen dynasty, which had legitimized its encroachments in the nineteenth century in terms of the "civilizing mission" of Confucianism, was persuasive. Thus, the new brand of indigenous communism that emerged after 1960 combined nationalist and revolutionary appeals and, when it could afford to, exploited the virulent anti-Vietnamese sentiments of the Khmers. Khmer Rouge literature in the 1970s frequently referred to the Vietnamese as yuon (barbarian), a term dating from the Angkorian period.

In 1930 Ho Chi Minh founded the Vietnamese Communist Party by unifying three smaller communist movements that had emerged in Tonkin, in Annam, and in Cochinchina during the late 1920s. The name was changed almost immediately to the ICP, ostensibly to include revolutionaries from Cambodia and Laos. Almost without exception, however, all the earliest party members were Vietnamese. By the end of World War II, a handful of Cambodians had joined its ranks, but their influence on the Indochinese communist movement and on developments within Cambodia was negligible.

Viet Minh units occasionally made forays into Cambodia bases during their war against the French, and, in conjunction with the leftist government that ruled Thailand until 1947, the Viet Minh encouraged 100 the fo formation of armed, left-wing Khmer Issarak bandÍÍÍÍs. On April 17, 1950 (twenty-five years to the day before the Khmer Rouge captured Phnom Penh), the first nationwide congress of the Khmer Issarak groups convened, and the United Issarak Front was established. Its leader was Son Ngoc Minh (possibly a brother of the nationalist Son Ngoc Thanh), and a third of its leadership consisted of members of the ICP. According to the historian David P. Chandler, the leftist Issarak groups, aided by the Viet Minh, occupied a sixth of Cambodia's territory by 1952 and, on the eve of the Geneva Conference, they controlled as much as one half of the country.

In 1951 the ICP was reorganized into three national units--the Vietnam Workers' Party, the Lao Itsala, and the KPRP. According to a document issued after the reorganization, the Vietnam Workers' Party would continue to "supervise" the smaller Laotian and Cambodian movements. Most KPRP leaders and rank-and-file seem to have been either Khmer Krom, or ethnic Vietnamese living in Cambodia. The party's appeal to indigenous Khmers appears to have been minimal.

According to Democratic Kampuchea's version of party history, the Viet Minh's failure to negotiate a political role for the KPRP at the 1954 Geneva Conference represented a betrayal of the Cambodian movement, which still controlled large areas of the countryside and which commanded at least 5,000 armed men. Following the conference, about 1,000 members of the KPRP, including Son Ngoc Minh, made a "Long March" into North Vietnam, where they remained in exile. In late 1954, those who stayed in Cambodia founded a legal political party, the Pracheachon Party, which participated in the 1955 and the 1958 National Assembly elections. In the September 1955 election, it won about 4 percent of the vote but did not secure a seat in the legislature. Members of the Pracheachon were subject to constant harassment and to arrests because the party remained outside Sihanouk's Sangkum. Government attacks prevented it from participating in the 1962 election and drove it underground. Sihanouk habitually labeled local leftists the Khmer Rouge (see Appendix B), a term that later came to signify the party and the state headed by Pol Pot, Ieng Sary, Khieu Samphan, and their associates.

During the mid-1950s, KPRP factions, the "urban committee" (headed by Tou Samouth), and the "rural committee" (headed by Sieu Heng), emerged. In very general terms, these groups espoused divergent revolutionary lines. The prevalent "urban" line, endorsed by North Vietnam, recognized that Sihanouk, by virtue of his success in winning independence from the French, was a genuine national leader whose neutralism and deep distrust of the United States made him a valuable asset in Hanoi's struggle to "liberate" South Vietnam. Champions of this line hoped that the prince could be persuaded to distance himself from the right wing and to adopt leftist policies. The other line, supported for the most part by rural cadres who were familiar with the harsh realities of the countryside, advocated an immediate struggle to overthrow the "feudalist" Sihanouk. In 1959 Sieu Heng defected to the government and provided the security forces with information that enabled them to destroy as much as 90 percent of the party's rural apparatus. Although communist networks in Phnom Penh and in other towns under Tou Samouth's jurisdiction fared better, only a few hundred communists remained active in the country by 1960.

Data as of December 1987