The origin of the war and killing field in Cambodia is somehow just the by-product of Vietcong war, especially the perpetuated attempt of Indochina Confederation maneuvered by Vietnam.
Indochinese Confederation primarily found and recognized by French colony or it was called French Union. In that time, French recognized Vietnam leadership to guide this union (read Vietnam Join the World for more detailed).
After that, when the war fought against America which were tremendously backed by China and Russia; Indochinese Community Party is created and it is officially recognized by China. Ho Chi Minh is the founder and also the leader of ICP to lead Lao and Cambodia. But when Lao and Cambodia felt not comfortable with this union/federation, Vietnam allowed to have Lao communist party and Cambodian communist party. However, Vietnam suggested to have mix committees within each party.
The Federation has been investigated and interrogated by international watchers, so that Vietnam changed it to be "Association" that stand on ideology of "mutual relationship". The objectives are "to preserve the special relationship between the Vietnamese people and the people of Laos and Cambodia; and to strengthen military solidarity, mutual trust, long term corporation and mutual assistance in all fields..."
Vietnam has no problem with Lao because Lao has never had any international agreement to recognize its border sovereignty. But Vietnam has some obstacles with Cambodia. Those obstacles happened with Cambodia during the signature of Geneva Agreement led by Somdach Ta N.Sihanouk and especially the Paris Peace Agreement in 1991.
However, the continuity of Association and Vietnam affiliation or interference inside Cambodia is still smoothly continuing in with an unopen manner. This manner is lighter than if we compare with Lao.
Influences of Vietnam inside Cambodia is being altered during Songkum Reastr Niyum of Somdach Ta N.Sihanouk, Lon Nol and Pol Pot. But Vietnam still had influences and organizing Cambodian insurgents such as Khmer Issarak who fought against N.Sihanouk, Pol Pot who once joined Vietnam to fight against America; and finally Khmer Vietminh group that once led by Achar Mien and their younger generation is present CPP's leaders.
Clearly, the federation that changed to association is still alive and operational inside Cambodia. It is dead during the Khmer Rouge, but re-survive again during the Vietnamese invasion in January 7, 1979. And it is nearly dead during the UNTAC in Cambodia, but it is re-survive again by the supplemental border treaty in 2005.
Legally, it has full status as mutual relationship with Cambodia and secretly it is potentially and possibly spreading spies and staffs inside Cambodia.
We need to study more about this, but the influence of Indochinese Association is still tight inside CPP. Only CPP who knows this better than us.
My article is not about correct or incorrect, it is about the survival of Cambodia. And it is not about anybody's propaganda; but it is about truth that CPP has to clarify in front of Cambodian populace that through the help of installing to power in January 7, 1997; how CPP can escape from such huge gratitude/repayment and what is CPP's future vision to free Cambodia from such Vietnam's trap?
CPP would have better vision for future of Cambodia; not to keep such rotten association with Vietnam, but they must keep modern legal diplomatic relation with every nation under the international standard of law, in order to survive the nation and build bright future of younger Cambodians.