The Sino-Vietnamese War, also known as the Third Indochina War, occurred in 1979 when troops from the People’s Republic of China attacked the Socialist Republic of Vietnam. This war came after the First Indochina War and the Vietnam War (or the Second Indochina War). The First Indochina War lasted from 1946 to 1954 and involved a conflict between China and the Soviet Union backed Vietnam and France to control the area called Indochina. While the communist People’s Republic of China connected Vietnam’s independence group The Viet Minh to the Soviets, their relationship with the Soviet Union soon became hostile, leading to the Sino-Soviet split and eventually China’s collaboration with the US against the Soviet Union. The Vietnam War lasted from 1955 to 1975 and included a major conflict between North Vietnam and South Vietnam. South Vietnam was anti-communist while North Vietnam was communist, backed by the Soviet Union. While communist China did not aid the US in support of South Vietnam, they were certainly fearful of the Soviet-Vietnamese relationship that was developing and threatening an increase in Soviet influence. Eventually, North Vietnam attacked and South Vietnam fell in 1975. These tensions all led up to the Sino-Vietnamese War.
Neighboring Vietnam and Cambodia once were cooperating nations, but their relationship deteriorated when the Cambodian Khmer Rouge leader Pol Pot came to power and established the Democratic Kampuchea on April 17, 1975. China, on the other hand, was a long time supporter of Cambodia, providing extensive political, logistical, and military support. Vietnam’s grievances with Cambodia reached a limit after numerous border clashes, and on December 25, 1978, Vietnamese forced invaded Cambodia. This greatly angered China, who wanted to strike back immediately but could not due to the 1950 Sino-Soviet Treaty of Friendship, Alliance and Mutual Assistance. So, they waited until February 15, when they could officially announce the termination of the treaty, and China’s Vice-premier Deng Xiaoping declared a limited attack on Vietnam.
The attacking party of Vietnam did not have a just cause nor a right intention to begin the war. They attacked Cambodia primarily because a democratic state was formed in contrast to the communist state of Vietnam and the Soviet Union. Nations have the right to declare their own government, and Vietnam was not just in beginning the Sino-Vietnamese War. The attacked party of China did, in fact, have a just cause and right intention to get involved in the war. China was supporting and defending its ally, the Khmer Rouge of Cambodia. Additionally, Vietnam was mistreating the ethnic Chinese minority in Vietnam, and they were inhabiting the Chinese Spratly Islands without permission. Both parties in the war were lawful authorities, and both parties had a hope of success.
As the war progressed, the belligerent forces of each country both seemed to observe the principles of necessity and proportionality in the use of force. China’s People’s Liberation Army of 600,000 greatly outnumbered the Vietnamese force of 70,000; however, China was facing both Vietnam and the ally of Vietnam: The Soviet Union. While the Soviet Union did not take direct military action, they provided intelligence and equipment to support Vietnam. They lent the Vietnamese military an airlift, multiple ships, tanks and armored personnel carriers, mortar artillery and air defense artillery, rocket launchers, missiles, jet fighters, and thousands of military advisors to train Vietnamese soldiers. The Soviet Union also deployed troops along the Chinese border to tie up Chinese troops; however, the Soviets refused to take any direct action.
As the People’s Liberation Army quickly marched through Vietnam, heading toward the capital of Hanoi, the Vietnamese avoided mobilizing most of their troops, holding back a majority to defend Hanoi. Avoiding direct combat, the People’s Army of Vietnam used guerilla tactics to slow down the Chinese instead. As the People’s Liberation Army continued to advance, they captured the city of Lang Son. Not wanting to escalate tensions with the Soviet Union, China declared the path to Hanoi open and that their mission was completed on March 6, 1979.
However, on the way back to the Chinese border, the People’s Liberation Army destroyed all local facilities and housing, and looted all their resources and equipment, greatly weakening the economy of Vietnam’s provinces. This is an example of China using disproportional force and having no mercy upon the Vietnamese, a direct violation of the just war principles.
While this unjust decision of the Chinese harmed the innocent Vietnamese populations, China also seemed to go to great lengths further than the Vietnamese military to attempt to preserve innocent civilian populations from unnecessary harm and destruction. Although China’s People’s Liberation Army greatly outnumbered the Vietnamese forces, the majority of their forces were not on the frontlines, but rather, along China’s northern border with the Soviet Union to deter Soviet intervention and prevent a wide-scale war. Also, instead of continuing to march on to the Vietnamese capital of Hanoi with the remainder of their troops like they easily could’ve done, China decided to withdraw in order to again prevent a larger and deadlier conflict including the Soviet Union.
Both sides of the war took prisoners of war, with the Chinese holding 1,636, and the Vietnamese holding 238. While it is unclear how exactly the Vietnamese prisoners were treated, the Chinese prisoners endured torture and inhumane treatment, such as being blindfolded and having their bodies bound and restrained with metal wire. This is an obvious violation of the just war principle of mercy.
Vietnam, in initiating the war by attacking Cambodia with no just cause nor right intention, and in not treating the Chinese prisoners with mercy, took part in an unjust war. China, though it observed the principles of just cause and right intention, and attempted in some ways to preserve the innocent civilian populations from unnecessary harm, did, in fact, violate the just war principle of proportional force through the looting and destruction of Vietnamese provinces, and therefore also took part in an unjust war.