In the late 1950s, with tacit support from the United States, a paramilitary right-wing group known as the Khmer Serei began plotting against Prince Norodom Sihanouk. This group was funded and backed by the Thai and South Vietnamese governments. As a result of these developments, Sihanouk grew increasingly distrustful of both the pro-American Thai and South Vietnamese regimes. Nevertheless, he continued to engage with the US and accept American military assistance, while simultaneously forging ties with China, which sought to counter US influence in the region.

However, in a significant shift, Sihanouk publicly accused the United States of providing arms to the Khmer Serei in mid-1963. By the end of that year, he ordered a halt to all US aid and initiated the nationalization of banking, insurance, and all import-export activities. These changes, combined with the tumultuous environment stemming from the ongoing conflict between North and South Vietnam, destabilized Cambodia’s economy.

Caught in a precarious balancing act, Sihanouk aimed to maintain a facade of neutrality and prevent Cambodia from being engulfed in the Vietnamese conflict. In 1963, he severed diplomatic relations with South Vietnam, which was receiving military and financial backing from the US, yet allowed American aircraft to traverse Cambodian airspace en route to bomb North Vietnam. Despite his efforts, Sihanouk could not stop North Vietnam from transporting troops and supplies through Cambodian territory to assist the Viet Cong in South Vietnam. Consequently, he felt compelled to sign a secret agreement with the North Vietnamese in 1966, granting them safe passage.

Simultaneously, the Communist Party of Kampuchea (CPK), later known as the Khmer Rouge, initiated an insurgency campaign in northeastern Cambodia. Composed of Cambodian communists who had found refuge in North Vietnam, the Khmer Rouge gradually gained momentum. Ironically, the US’s covert bombing campaign—codenamed Operation Menu—contributed to the Khmer Rouge’s eventual success. Launched over supposedly neutral Cambodia, the operation aimed to dismantle communist bases and supply lines in the southern provinces along the Vietnam border. From March 1969 to January 1973, over half a million tons of ordnance were dropped during three thousand bombing raids. This widespread destruction alienated many rural Cambodians, pushing them toward support for the CPK.

As tensions mounted and the bombing escalated, Cambodia found itself on a tragic trajectory towards war, setting the stage for profound and lasting consequences for the nation and its people.