Sihanouk, who had been out of the country at the time of the coup, had been walking a fine line for years between the Americans and the North Vietnamese– he allowed the U.S. to conduct strategic bombing against NVA targets inside Cambodia while at the same time he was the one who granted those same NVA troops sanctuary within his borders. Sihanouk was desperate to keep his country out of the fighting war so he played both ends against the middle, and was remarkably successful at it. In the end it was his inability, or lack of effort, to stop supplies destined for the NVA and Viet Cong from traversing his ports and countryside that finally led the US to support his removal.
Ousted unceremoniously, Sihanouk was quick to respond. He did so by aligning himself with Cambodian Communists, known as the Khmer Rouge. His hope was for a lightning counter-strike to oust Lon Nol’s regime and regain power. With hindsight we know that was a pure pipe dream.
The Khmer Rouge are led by an unknown figure named Pol Pot, who eagerly capitalizes on the enormous prestige and popularity of Prince Sihanouk to increase support for his Khmer Rouge movement among Cambodians.
March 20, 1970 – Cambodian troops under Gen. Lon Nol attack Khmer Rouge and North Vietnamese forces inside Cambodia. At the White House, Nixon and top aides discuss plans to assist Lon Nol’s pro-American regime. These discussions will lead to President Nixon‘s decision to invade Cambodia later that spring.
That invasion was a turning point late in the American phase of the war– in the United State it came as a great shock to a nation weary of the war and led to widespread protest, including Kent State and Jackson State; in Cambodia Lon Nol was temporarily saved but the Khmer Rouge and the NVA, previously at odds for the most part, were pushed into an alliance of convenience.
Combined with the endorsement from Sihanouk, contact with the NVA greatly enhanced the strength and prestige of the Khmer Rouge. When the American invasion bogged down, after the troops were pulled back out, a vacuum was left in the Cambodian countryside. The Khmer Rouge effectively exploited it.
Pol Pot would go on to violently oust Lon Nol and then enforce a radical experiment to create an agrarian utopia, resulting in the deaths of 25 percent of the country’s population (2,000,000 persons) from starvation, overwork and systematic executions.
In a very real sense then, the overthrow of Prince Sihanouk by Lon Nol, with America’s backing, set the stage for what came later– the horrific Cambodian genocide orchestrated by Pol Pot and his henchmen.
Another item of note took place on this date in the Vietnam conflict:
March 19 -21, 1965 – The first US Army troops arrive in South Vietnam. Just a couple of weeks after the 3rd Marines landed at DaNang the 716th Military Police Battalion lands at Tan Son Nhut Airport, Saigon. In the next few years over a million will follow. By 1968 Tan Son Nhut would become the world’s busiest airport!