By the April 1975 communist victory, Pol Pot and his close associates occupied the most important positions in the KCP and in the state hierarchies. He had been KCP general secretary since February 1963. His associates functioned as the party's Political Bureau, and they controlled a majority of the seats on the Central Committee. Khieu Thirith's management of youth groups meant that Pol Pot had ample reserves of zealous young cadres, "the nucleus and wick of the struggle," committed to imposing the party center's will throughout the country. But his domination of the revolutionary movement was not complete. In different areas of the country, especially in the Eastern Zone, pro-Vietnamese and veteran Khmer Issarak commanders were jealous of their independence. They questioned, and at times openly defied, his policies of revolutionary terror and hostility toward Vietnam. The highest ranks of the party were not free of dissension.

Like Joseph Stalin in the late 1920s and in the 1930s, Pol Pot initiated a purge of his opponents, both imagined and real. In terms of the number of people liquidated in relation to the total population, the Khmer Rouge terror was far bloodier than Stalin's. Through the 1970s, and especially after mid-1975, the party was shaken by factional struggles. There were even armed attempts to topple Pol Pot. The resultant purges reached a crest in 1977 and 1978 when hundreds of thousands of people, including some of the most important KCP leaders, were executed.

Data as of December 1987