The “Free Cambodia” move-ment first came to life in Bangkok on 20 December 1940, when the Thai government, at odds with the French over western Indochina, allowed a Cambodian nationalist-minded monk, Phra Phiset Panich or Poc Khun to create the Khmer Independence Party (Phak Khmer Issarak). Chaovalit and Khuang Aphaiwong, Thai politicians with ancient family links to western Cambodia, were strong supporters of the Khmer Issarak movement. This support continued into the Indochina War, as the Thais tried to hold on to Cambodia’s western provinces of Battambang and Siemreap, which the Japanese had helped them obtain from the French in 1941. Their efforts came to naught, however, when the Thai government, under U.S. pressure, retroceded the territories to the French in November 1946 and the Conciliation Commission designed to hear Thai desiderata closed in early September 1947.
Shortly thereafter, the French High Commissioner to Indochina, Émile Bollaert, sent a report to Paris explaining the importance of putting an end to the Khmer Issarak and Lao Issara independence movements in Thailand, both of which undermined French efforts to build up and legitimize pro-French states in Laos and Cambodia. In mid-1947, the French moved to rally these “dissident elements” to the French cause in Indochina. The French Commissioner in Cambodia Léon Pignon, entered into contact with Poc Khun (and Prince Phetxarāt) in the hope of wooing him away from the Thais. Pignon promised a total amnesty to the Khmer Issarak partisans if they returned to Cambodia. While Poc Khun stayed put, many Khmer Issarak returned to Cambodia.
Meanwhile, Vietnamese communists, like their French adversaries, were keen on attracting the Khmer Issarak movement to their cause. In early 1948, the Indochinese Communist Party (ICP) revived its Indochinese revolutionary vision and moved to create a new Cambodian nationalist front, based in Cambodia and allied with the Vietnamese, called the “Committee for the Liberation of Kampuchea”. The Vietnamese explained that this committee would serve as a “provisional govern-ment” in opposition to the one the French were creating. The Vietnamese-backed Cambodian Committee would later constitute a National Assembly and thereby establish a permanent government. In charge of this revolutionary state-building project was Nguyen Thanh Son, the ICP’s most important official in charge of Vietnamese activities in Cambodia. Thanks to his efforts, the Committee came to life in the Dangrek hills in mid-August 1948, led by Dap Chhuon and seconded by Poc Khun.
However, as in Laos, it was the arrival of the Cold War in 1949–50 and French moves to create the Associated States of Indochina in Laos and Cambodia that led the ICP to create a revolutionary party and resistance government for Cambodia. The defection of Dap Chhuon in 1949, like much of the Lao Issara in that same year, caused a crisis for the ICP. As a result, the ICP assigned the task of creating a new government and party for Cambodia to Nguyen Thanh Son, head of the Committee for External Affairs (Ban Ngoai Vu) and Hoang Van Hoan, chief of the all-powerful Overseas Party Affairs Committee (Ban Can Su Hai Ngoai) based in Thailand. After a meeting in Bangkok in 1949, Nguyen Thanh Son returned to Indochina and created the Party Affairs Committee for all of Cambodia (Ban Can Su Toan Mien), the single most powerful revolutionary organization in all of Cambodia and run by the ICP.
In March 1950, as in Laos a few months later, the ICP organized a Cadres Congress for Cambodia bringing together Issaraks from across the country to create a new national front, provisional government, and revolutionary party. During this meeting held in Ha Tien, Vietnam, the delegates outlined the future Cambodian Resistance Government and its revolutionary tack. In April, the Representative Assembly for all of Cambodia (Cuoc Dai Bieu Hoi Nghi Toan Mien/Moho Sannibat Tamnang I’sara’ Nokor Khmaer) formed a new “Unifed National Front of the Khmer Issarak” (Mat Tran Issarak Thong Nhut Toan Quoc or Sammakum Khmaer I’sara in Cambodian) and created a Provisional Central Committee of National Liberation (Uy Ban Giai Phong Dan Toc Trung Uong Lam Thoi or Kana’ Cheat Mukkakeaha Mochchhoem Nokor Khmaer in Cambodia), based on the Viet Minh model. Son Ngoc Minh and other Cambodian luminaries were present. However, creating a revolutionary party for Cambodia was much harder. It was only in mid-1951 that the Party Affairs Committee for Cambodia finally created the People’s Revolutionary Party for Cambodia with Son Ngoc Minh at its helm. Nguyen Thanh Son, backed by Le Duc Tho and Le Duan, was its caretaker. See also ADMINISTRATIVE OFFICE FOR THE FRONTIER; COMMITTEE FOR THE EAST, LAO ISSARA; MÉTIS.