The 200,000 Vietnamese troops supporting the PRK, as well as Khmer Rouge defectors, had ousted the Democratic Kampuchea regime of Pol Pot, and were initially welcomed by the majority of Cambodians as liberators.

On 5 January 1979 a "Committee for a Neutral and Independent Cambodia" (Comité pour un Cambodge Neutre et Indépendant, CCNI) was established in Paris composed of Son Sann (a leading Cambodian neutralist, ex-President of the National Bank of Cambodia, and Prime Minister from 1967 to 1968), Sim Var, Yem Sambaur, Hhiek Tioulong, Nong Kimmy, Thonn Ouk and Chai Thoul.

Immediately the Royal Thai Government approached Son Sann with offers of support for a non-communist resistance force.

[3] In February 1979, General Dien Del and Nguon Pythoureth flew to Thailand to form the Khmer People's National Liberation Armed Forces (KPNLAF).

[5] The KPNLF was thus established as a right-wing, pro-Western, anti-Communist political faction in opposition to the Vietnamese-installed and backed People's Republic of Kampuchea.

[6] US President Ronald Reagan authorized the provision of aid to KPNLF in an effort to force an end to the Vietnamese occupation.

At the same time, the Reagan Administration gave new flexibility to the funds, permitting the NCR to purchase US-made weapons in Singapore and other regional markets.

[8] Since its beginning, the KPNLF had depended on international financial aid to help maintain their civilian camps and carry out military operations.

This increased financial aid because it appealed to the "Western" forces that were interested in ousting the Vietnamese yet not supporting the Khmer Rouge.

In order to increase their political clout and legitimacy, the KPNLF joined with the Khmer Rouge (at this point in time officially called the Party of Democratic Kampuchea) and Prince Sihanouk's United National Front for an Independent, Neutral, Peaceful, and Co-operative Cambodia (FUNCINPEC) to form the Coalition Government of Democratic Kampuchea (CGDK).

Even though both the KPNLF and FUNCINPEC did not agree with the Khmer Rouge's philosophy and methodology, they still joined the CGDK for the increased international legitimacy and recognition.

Established originally in March 1979 by General Dien Del, it was commanded by Sak Sutsakhan from 1981–1992 (with the exception of some power struggles).

Despite this military tendency to act in the form of individual unit attacks, occasionally the KPNLAF would join with other separatist forces to launch a large-scale assault on a specific target or area.

Even after the huge loss of approximately 30% of its men and material, the KPNLAF was still able to carry out guerrilla operations for the rest of its existence.

On the other side were the usurpers led by military commander Sak Sutsakhan, his chief of staff Dien Del, and party members Abdul Gaffar Peang Meth and Hing Kunthorn.

On the other hand, for Abdul Gaffar Peang Meth and Hing Kunthorn, Sann believed that disciplinary action was necessary in order to rejoin the party.

As the months wore on, Thai authorities became concerned with the KPNLF and in particular, the KPNLAF's abilities to wage war against the PRK because of divided leadership.

While Sann was allowed to keep the title of the presidency and many of the civilian powers that go with it, Sutsakhan retained his military command of both the faction and joint operations between the KPNLAF and FUNCINPEC.

The name change did not result from a deviation in the platform or structure of the KPNLF, with the exception of the loss of the KPNLAF and the previously mentioned Sutsakhan breakaway party.