The Vietnam War was ostensibly a civil war between the communist North and pro-Western South. Yet the Vietnamese didn’t do all the fighting. The United States and many other countries intervened, propping up both sides—but especially South Vietnam—with troops, weapons and supplies and turning what started as a small guerrilla uprising into a major Cold War-era conflict.
Below is a list of nations that played a role in the Vietnam War, and details on what motivated them to get involved.
READ MORE: Vietnam War Timeline
France had been a long-time occupier of Vietnam before 1954. It wanted no part of the new conflict.
After World War II, France reoccupied Vietnam as part of its attempt to reclaim its prewar empire. “The French had controlled Vietnam for a couple of generations,” explains Ed Moise, a professor of history at Clemson University and author of Tonkin Gulf and the Escalation of the Vietnam War. “They were determined to go on holding it, both as a matter of national pride and because if they let one colony go loose, then the others might get ideas.”
Most Vietnamese, however, opposed colonial rule, and a rebellion broke out led by communist and pro-independence leader Ho Chi Minh. In 1954, Ho’s forces won a decisive victory at Dien Bien Phu and succeeded in evicting the French once and for all.
When the Second Indochina War, or Vietnam War, as it’s known in the United States, began soon after, France stayed well away. In fact, French President Charles de Gaulle warned his U.S. counterpart, John F. Kennedy Jr., that Vietnam would be a “bottomless military and political swamp.” Though prescient, the advice ultimately went unheeded.
The United States got involved to prevent South Vietnam from falling into communist hands. At first, the U.S. operated behind the scenes, but after 1964, sent combat troops and became more deeply mired in the war.
Following France’s defeat in the First Indochina War, an international agreement divided Vietnam in two. Ho led the North, whereas the U.S.-backed Ngo Dinh Diem took charge of the South. Elections were planned to reunite the country within two years, but Diem, with U.S. approval, never submitted to a vote that he feared losing. Instead, a communist insurgency broke out, pitting the so-called Viet Cong, who were sponsored by North Vietnam, against Diem’s forces.
Determined to prevent South Vietnam from falling into communist hands, the United States propped up Diem with billions of dollars in aid, as well as increasing numbers of military advisers. As the Pentagon Papers later revealed, “the Diem regime certainly, and an independent South Vietnam almost as certainly, could not have survived” without U.S. help.
U.S. officials eventually soured on Diem, tacitly approving a 1963 coup that resulted in his death. Yet their support for South Vietnam never wavered, no matter who occupied the White House.
After a while, “no one thinks they’re going to win,” says James McAllister, a political science professor at Williams College, “but they’re damn sure a loss is not going to take place under their watch.”
At first, the United States largely operated behind the scenes. In 1964, however, the so-called Gulf of Tonkin incident prompted President Lyndon B. Johnson to commit combat troops and launch a massive bombing campaign, and U.S. involvement only deepened from there.
By the time American forces finally withdrew in 1973, about 2.7 million U.S. soldiers had served in Vietnam, more than 58,000 had died, and the nation had racked up a staggering bill of at least $111 billion (plus billions more in non-military costs).
The French and American experiences in Vietnam differed in many respects. Yet, as Moise points out, they both learned one important lesson: “It’s dangerous to get in a fight when the other side cares about winning more than you do.”
Despite being in bad economic shape at the time, newly Communist China aided Ho during the war with the French, and did so again during the war with the Americans, providing weapons, expertise, and manpower. All told, the Chinese claimed to have spent over $20 billion in support of North Vietnam and deployed 320,000 military personnel, more than 4,000 of whom died.
For the most part, the Chinese stayed in the background, rebuilding areas destroyed by U.S. bombs and manning anti-aircraft batteries. But perhaps their biggest role was preemptive: They made it clear that if U.S. ground troops invaded North Vietnam, then they would respond in kind.
Unlike during the Korean War, the United States yielded to this threat. “Their function is as a tripwire,” Moise says, “a warning to the Americans: ‘Don’t go too far… or you’ll be fighting us.’”
China and the Soviet Union didn’t have to do as much as the Americans, Moise explains, because they were buttressing the stronger side. Nonetheless, “if there had been no Chinese or Soviet support, the North Vietnamese could not have won,” he says, pointing out that the U.S. military budget was roughly 30 times greater than the entire gross national product of North Vietnam.
As the original communist state, the Soviet Union aided North Vietnam, with increasing support in the late 1960s. While the U.S.S.R. supplied some troops, their biggest contribution was in weaponry.
Though it originally took little interest in the Vietnam War, the Soviet Union secretly ramped up its aid to North Vietnam following Nikita Khrushchev’s fall from power. The Soviets wanted to “make life difficult for the United States,” McAllister says, “but they didn’t want to do it in a way that got them in a conflict with the United States.”
Soviet involvement in the war increased in the late 1960s, just as China’s influence was lessening. (The two countries were undergoing a bitter split at the time.)
Among other weapons, the USSR provided surface-to-air missiles that the Chinese weren’t yet technologically capable of producing. The Soviets even allegedly shot down some U.S. planes. Overall, though, they pumped only about 3,000 troops into the conflict, far fewer than the Chinese.
Laos was originally neutral in the conflict, but the North Vietnamese moved troops through the country and supported a communist insurgency. That insurgency drew heavy U.S. bombing.
In 1962, the United States, both Vietnams, and several other nations agreed to respect the neutrality of and not interfere in the affairs of Laos, which borders Vietnam to the west. North Vietnam immediately broke the accord, however, moving troops and supplies through Laos rather than traversing the heavily guarded demilitarized zone that separated it from South Vietnam.
The North Vietnamese also came to dominate a communist insurgency against the royalist government of Prince Souvanna Phouma, relegating the local Laotian Communists to what Moise describes as “junior partners.”
In response to these North Vietnamese transgressions, the Americans covertly rained down billions of pounds of bombs on Laos. The nine-year campaign was so intense that, on average, a planeload of explosives fell every eight minutes, making Laos, per capita, the most heavily bombed nation on earth. Unexploded munitions from the Vietnam War-era continue to kill Laotians (and Vietnamese and Cambodians) to this day.
Meanwhile, President Richard Nixon authorized a cross-border invasion of Laos in 1971. Yet, no matter what they tried, the Americans never succeeded in seriously disrupting North Vietnamese supply lines, nor did they prevent the fall of Laos to the communists in 1975.
Cambodia, while officially neutral, tolerated communist intrusions—and was bombed by the United States for those intrusions.
Unsurprisingly, the North Vietnamese likewise moved troops and supplies through neighboring Cambodia, which, though officially neutral, tolerated the communist intrusions.
Prince Norodom Sihanouk “basically felt that he was surrounded by dangerous enemies, and he had to make nice with some of them,” Moise says, adding that “he could not afford to offend” the North Vietnamese despite being “anti-communist in Cambodian politics.”
The United States responded with a secret bombing campaign that Nixon drastically ramped up in 1969. Nixon then sent troops across the border in 1970, taking advantage of a coup that ousted Sihanouk in favor of a pro-American general.
U.S. bombs killed tens of thousands of Cambodians, which, some historians contend, may have increased popular support for the Khmer Rouge, a communist insurgency group that initiated a brutal genocide upon taking power in 1975.
Though Vietnamese communists allied with the Khmer Rouge during the Vietnam War, they eventually deposed the regime in 1979.
South Korea and Other U.S. Allies
South Korea was the main U.S. and South Vietnamese partner, contributing more than 300,000 troops to the war.
Not wanting to be seen as going it alone, the Johnson administration pressured other countries to join in the Vietnam War, much as George W. Bush would later form a “coalition of the willing” to fight in the Iraq War.
South Korea was the main U.S. and South Vietnamese partner, providing over 300,000 troops and suffering some 5,000 deaths. “The Koreans sent more troops and much more aggressive troops [than other U.S. allies],” Moise says.
He explains that they were partially motivated by a sense of obligation and ideological sympathy: After all, they could not help but notice the historical parallels between themselves and South Vietnam. However, they were also being paid off by the United States in the form of economic and military assistance.
Financial aid, along with a desire to curry favor with the United States, drew in additional countries as well. So, too, did a legitimate fear of Communism, Moise says.
In the end, almost 60,000 Australians served (521 of whom died), about 40,000 Thais served (321 of whom died), and over 3,000 New Zealanders served (37 of whom died). The Philippines, Taiwan and Spain likewise aided the U.S. war effort, whereas on the communist side North Korea and Cuba purportedly sent token support.
The Vietnam War was described as a civil war within South Vietnam, although it became a proxy war between Cold War powers. As a result, the Vietnamese suffered the highest casualties in the conflict.
Brutal tactics were the norm during the Vietnam War, and no one suffered more than the Vietnamese themselves, both in the North and the South. By 1975, when North Vietnamese troops took Saigon and reunified the nation under communist rule, an estimated 1 million to 3 million Vietnamese had perished, many of them civilians.