Historically, and with few exceptions, the creation of states is usually a long and bloody process. In this sense, the birth of the Socialist Republic of Vietnam was a painful birth because it could only come after decades of wars waged against the French colonizers first and the Americans, allies of the southern faction, later. But even with it all over and unification achieved, the Vietnamese were barely able to enjoy four years of peace before having to take up arms again, this time against their Cambodian and Chinese neighbors.
To understand the situation, it must be remembered that, although from the outside the communist bloc tended to be seen from a monolithic perspective, internally it was not so monolithic and it branched out into tendencies that sometimes differed considerably in terms of methodology. The USSR played a unifying role until Stalin’s death and Khrushchev’s new policy that denounced his predecessor’s period, something that began to cause internal division in the East.
The first, that of Mao, whose line was the one that the Khmer Rouge (a communist guerrilla) would adopt in Cambodia, against the Vietnamese Viet Minh, more reluctant to that dissidence. The Cultural Revolution accentuated these differences and in 1968 China and the Soviet Union came to war in a minor (six months) but significant border conflict.
Curiously, Mao died in 1976 and was replaced by Den Xiaoping, who began a process of dismantling the previous regime that was somewhat reminiscent of Krushev’s with Stalin. However, he found a good ally in Cambodia despite the Maoist leanings of the Khmer. These, after overthrowing the military dictatorship of Lon Nol and seizing power, had collaborated with the Vietnamese offering refuge to the Viet Cong and that is why the American bombings reached their territory.
But that relationship began to break down on April 17, 1975, when the so-called Democratic Kampuchea was proclaimed. The Cambodian leader, whose identity until then had remained anonymous for security reasons, turned out to be Saloth Star, better known as Pol Pot, who denounced a series of sabotages that ultimately revealed both the ideological clash between communist factions and territorial aspirations over the Mekong Delta.
Thus, he decided to deal with the issue expeditiously, so that the border between the two countries began to boil with various armed confrontations. There were ups and downs and attempts to agree but without concretizing. In 1977 the tension escalated and there was an open war, already with bombings and important mobilizations of soldiers. In this context, the massacres ordered by the Cambodian regime among the peasants of Vietnamese origin would become famous, which, added to the victims of the famine caused by a disastrous economic policy and the reprisals suspected of being Pro-Vietnamese, added millions of deaths.
Finally, a rapid (fourteen days) and forceful (one hundred and twenty thousand men) operation allowed the Vietnamese General Giap to take Phnom Penh on January 7, 1979, changing the name of the country to the People’s Republic of Kampuchea. The Kampuchean government took refuge in the rural area and started a guerrilla war, but a new and unexpected chapter also opened: China’s meddling in defense of its ally barely a month later.
The truth is that this new contender was not just for ideology. Vietnam had carried out a harsh repression of the ethnic minorities of Chinese origin that lived on its common borders, causing a veritable exodus of them: the Thu Lao, the Phù Lá, the Hmong… As well as, the previous year, Hanoi had signed a reciprocal defense pact with Moscow whose purpose the Chinese interpreted as being to confront them, and that Vietnam had occupied the Spratly Islands (an archipelago historically disputed by several Asian countries), the Beijing government prepared for war.
“The boy is getting naughty; It’s time to get hit” Den Xiaoping told Jimmy Carter very expressively during a visit to the US. And so, on February 17, 1979, and after warning the USSR to stay out of it (it even evacuated the border towns with it), the Chinese 41st and 42nd armies attacked the northern Vietnamese provinces of Cao Bang, Lao Cai and Lang. .
North American satellites indicated that Beijing had mobilized nearly two hundred thousand soldiers in that area. Quite a problem for Vietnam, which had the best of its troops in Cambodia and only had about 70,000 troops between regular troops and border guards. The People’s Liberation Army, as the Chinese forces were called, advanced in two directions, east and west, while their enemy turned to guerrillas.
The conflict lasted twenty-seven days. The heaviest fighting occurred in the city of Lang Son, which the Chinese took on March 5 with great difficulty, fighting house to house. There were more battles (Dong Dang, Lao Cai and Cao Bang) but his initial momentum gradually waned, suffering heavy casualties (20,000) and failing to get Hanoi to move his forces from Cambodia, as envisioned in the original plan.
Things threatened to turn the other way, because although the USSR did not intervene directly, except for some border skirmishes, it did provide the Vietnamese with abundant material (four hundred tanks, half a thousand guns, surface-to-air missiles, twenty jet fighters, thousands of military advisers…), logistical support (an airlift between Cambodia and the attacked provinces to transport troops from one to another) and communications from fifteen ships anchored on the coast of their ally.
The Chinese had been prudent in developing a limited rather than total war, not only from the point of view of territory but also from the force used, leaving aviation and the navy almost to the side. This worked for him by convincing the USSR to grant limited support to Vietnam and, consequently, Beijing continued in that line: on March 16 it ended the hostilities, classifying them as a mere punitive operation and withdrawing its troops.
It is impossible to determine the number of victims, since each side gave its version and, as you can imagine, one is very different from the other. It is known that prisoners were exchanged over the following two months and that the peace achieved did not prevent sporadic clashes on the borders in the first half of the 1980s.
Interestingly, the withdrawal gave China some recognition among the surrounding countries while Vietnam, which continued to occupy Cambodia, began to be viewed in a bad light. It was not until the country was abandoned in 1989 that the situation normalized and in 1999 the Chinese and Vietnamese signed an agreement to delimit their borders and partially demilitarize the area.
The Other Story of the Vietnam War (Jonathan Neale)/China at war. an encyclopedia (Xiaobin Li)/A History of the Modern Chinese Army (Xiaobin Li)/Chinese Military Strategy in the Third Indochina War. The Last Maoist War (Edward C. O’Dowd)/Kampuchea Between China and Vietnam (Pao-min Chang)/Wikipedia