South Vietnamese M113 Armored Personnel Carries in Cambodia in 1970.
Recalled now most as the "U.S. entering the Parrot's Beak" region of Cambodia, in fact events had been building in this direction for weeks, months and years.
Cambodia was part of French Indochina, along with Vietnam and Laos, coming into French control due to a long struggle between Thailand and Vietnam for control of the country, which left it in Vietnamese hands at the time that Vietnam was colonized by the French. Like Loas, it became an independent kingdom with the collapse of the French regime, achieving that status in 1953 prior to the French departure from Vietnam. The establishment of the independent kingdom demonstrated to a degree how the French envisioned post colonial Indochina, with it being made up of French aligned independent states with a government of a highly traditional model. Indeed, the installed regent, Prince Sihanouk, was a French choice and installed much like the last Vietnamese emperor was in neighboring South Vietnam. In Sihanouk, however, the French had chosen a much stronger personality who soon demonstrated that he could not be controlled.
Indeed King Sihanouk resigned his position in 1955 to become a politician in the newly independent kingdom, which made his father the king. However, upon his father's 1960 death, he resumed the position of monarch, but limited his title to Prince.
Right from the onset Cambodia, like the other regions of Indochina, contained left wing radicals who had come up during the colonial period, something that isn't really surprising in light of the fact that France also had left wing radicals itself. And as with South Vietnam, the established government was not sympathetic to democratic elements. Differing from Vietnam, however, Cambodia's monarchy survived its early independence and went on to form the government, whereas a similar effort in the Republic of Vietnam had left to a rapid downfall of the monarch. Sihanouk had no small role in navigating this course.
Things were always accordingly troubled in the country but the ongoing wars in its Indochinese neighbors made things particularly difficult for Cambodia. Prince Sihanouk attempted to place the country in the nonaligned camp, which was understandable under the circumstances but frankly naive given the enormous nature of the local conflict and the overarching global one.
U.S. Air Force UH-1 helicopters over Cambodia.
On the other hand, the Prince correctly believed that the Communists would ultimately prevail in the Vietnamese War and believed that he had to be capable of dealing with that reality if Cambodia was to remain an independent state. Perhaps realistically assessing the strength of his own armed forces as too weak to oppose the North Vietnamese, his government allowed the NVA to establish sanctuaries within the country starting in the mid 1960s, although as early as 1967 he commented to an American reporter that he would not oppose American air strikes in the country as long as they did not hard Cambodians, which of course was an impossible limitation.
In contrast right wing elements in the country increasingly wanted to take it in the opposite direction and found the Vietnamese presence humiliating. Cambodia had its own culture and ethnicity and had long suffered from Vietnamese incursions into the country. Indeed, large number of ethnic Cambodians lived in the Mekong are of Vietnam which itself was a sore point to the Cambodians that would continue right on into the Communist Pol Pot era.
In 1967 things changed for the worst when a spontaneous Communist rebellion took place in a region of the country which was followed by a more planned one in 1968. In the same year Sihanouk openly revoked his prior comments about allowing US air strikes in the country, which given the increasing deterioration of his government's situation was probably a logical position for him to take. By that time, however, the war in Vietnam was now highly developed.
With Richard Nixon's election in 1968 the US began to increasingly look towards action in Cambodia aimed at North Vietnamese enclaves there, something comparable to other frontier battles of other eras in which the US sought to address safe harbors across a border. Following the Tet Offensive and Nixon's election, moreover, the US began to look for ways to withdraw from Vietnam which ironically meant occasional increases in the level of violence in the war. In January 1969 Prince Sihanouk indicated to the US that Cambodia would not oppose ARVN and US forces that entered Cambodia in "hot pursuit" of retreating NVA forces provided that no Cambodians were harmed. The US went one step further however and started targeting B-52 air strikes on NVA enclaves in the country, something the US later claimed that Sihanouk agreed to but which he most likely did not. The events demonstrated the impossibility of the Cambodian position, however, as an allowance of one thing is practically an allowance of another, in war, and at the same time it was becoming increasingly impossible for the US to abstain from action in Cambodia.
In March, 1970 Sihanouk was deposed in a military coup which was supported by most of the educated urban population. The kingdom was brought to an end and the Khmer Republic established. A massacre of Vietnamese residents of Cambodia ensued in which thousands lost their lives and which was condemned by both North and South Vietnam. By that time there were 40, 000 North Vietnamese troops in the country. The new republican regime demanded that the North Vietnamese and Viet Cong withdraw but instead they commenced attacks on the Cambodian state. Prince Sihanouk, moreover, would not give up and encouraged his supporters to restore him to power. All of this fueled the native communist insurgency and the situation degraded into a civil war. During the same period the NVA attacks became a full scale invasion and the NVA began to overrun and defeat Cambodian army positions. Not really well known into the 1990s, the North Vietnamese in the period sound to completely overrun the country, which likely was regarded by them as a strategic necessity. They scored significant successes in the early months of 1970 in attempting this but, remarkably, the Khmer government did not completely collapse and in fact its armed opposition to the NVA and the Khmer Rouge continued throughout the period, although they were losing ground.
The South Vietnamese and American incursion of 1970 was designed to defeat the North Vietnamese in their safe harbor. South Vietnamese preparatory actions commenced on April 14. Perhaps ironically President Nixon announced the withdrawal of 150,000 U.S. troops from South Vietnam on April 20. Nonetheless plans for the action continued, and indeed they may be seen as related to some degree. On April 30 the South Vietnamese invasion began in earnest and President Nixon announced to the nation that U.S. troops would be entering Cambodia on a temporary basis, which they commenced to do the following day, May 1.
U.S. M48s in Cambodia.
The North Vietnamese were surprised by the invasion and proved to be incapable of resisting it. They nonetheless proved adept at avoiding having their forces destroyed. American leadership regarded the invasion as a success and US and ARVN forces would withdraw from the eastern portions of the country they occupied in July. The expansion of the war at the very time that the Administration was committed to withdrawing, while not actually strategically inconsistent, appeared to be and it increased opposition to the war in the United States. The Cambodian government, in contrast, welcomed the incursion and hoped that US forces would remain in the country, an act which they believed would have helped them combat the native Khmer Rouge insurgency and which they also hoped would lead to the permanent expulsion of the North Vietnamese Army from the country. Indeed, a remaining American presence was practically a necessity for the Khmer Republic's survival.
Newspaper reading American soldier in Cambodia.
To some degree the action is a tribute to the late Vietnam War American Army and the Army of the Republic of Vietnam. The ARVN were much more fully formed and combat ready by this point in the war than they had been earlier, although they'd also become completely dependant upon American air support, which was enormous in the invasion. The American Army, in contrast, was severely strained and suffering gigantic moral and discipline problems by this point, so the fact that they were able to effectively rally for a major offensive action is impressive. It's also impressive, however, that the North Vietnamese were able to react to the invasion and avoid complete destruction.
There are those who want to attribute the ultimate collapse of the Khmer Republic, followed by the horror of Communist Pol Pot's regime, to this series of 1970s events, but the claim is frankly strained. As noted, the Cambodian government of the time was becoming increasingly right wing and hostile to Communism inside the country and it was actively seeking to destroy it, albeit unsuccessfully. A more realistic assessment would be that the results in neighboring South Vietnam were always set to dictate what happened in the smaller Indochinese neighbor. The same political forces that had existed in South Vietnam since 1954 were present in Cambodia since 1953 except, ironically, right wing elements that wished to actively oppose Communism were significantly stronger in Cambodia.
Cambodian civilians dividing captured North Vietnamese Army rice.
At any rate, the Cambodian tragedy, in some ways, has always been strongly linked to being a small country between two larger neighbors. Vietnam's civil war had spilled into it and now it was raging within its borders. It's fate would now follow a strongly parallel, but more tragic and bloody course.