[a] During the Cold War it allied itself with Vietnam and the Soviet Union, in contrast to the pro-Chinese Communist Party of Kampuchea led by Pol Pot.

However, the triumph of the Japanese during the early stage of World War II crippled French rule and helped to nurture nationalism in all three Indochinese countries.

In Cambodia, growing nationalist sentiment and national pride married historical mistrust and fear of neighbouring countries, which turned out to be a stumbling block for the ICP.

On 28 June 1951, the Cambodian nationalists who struggled to free Cambodia from French colonial rule split from the ICP to form the Kampuchean People's Revolutionary Party (KPRP).

Members of the CPK moved the party's headquarters to Ratanakiri Province, where they were termed "Khmer Rouge" by Prince Norodom Sihanouk.

As of 1990, members of the Politburo were Heng Samrin (General Secretary), Chea Sim, Hun Sen, Chea Soth, Math Ly, Tea Banh, Men Sam An, Nguon Nhel, Sar Kheng, Bou Thang, Ney Pena, Say Chhum and alternate members included Sing Song, Sim Ka and Pol Saroeun.

Ideologically, an increasing number of CPP senior leaders claim that the Cambodian ruling party has adopted a centrist position.

However, academics such as John Ciorciari have observed that the CPP still continues to maintain its communist-era party structures and that many of its top-ranking members were derived from KPRP.

Political scientists Radek Buben, Elvin Franisco Rodríguez Fabilena and Karel Kouba classify the CPP under Hun Sen as left-wing, comparing it to the Sandinista National Liberation Front in terms of both authoritarian governance and representing formerly far-left revolutionary organizations that transitioned into a more reformist type of governance.

[21] Sreinith Ten also argues that the party "had embedded the legacy of communism based on Marxist-Leninist ideology", and continues to cling onto socialist-oriented rhetoric and policies to maintain legitimacy, such as through promoting gender egalitarianism and establishing state-backed organizations such as the Kampuchea Revolutionary Women's Association.