South Vietnam was helped by US. Even when the US was gone, they had a 1 million army.

So why did they lose?

Even without US support, South Vietnam had about the same manpower, higher technology, and was more industrialized. Why did they lose?

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    The South was invaded in a regular war by the North. Commented Dec 17, 2011 at 13:19
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    I'll forego a lengthy analysis and simply recommend a book by someone who knows a thing or two about this subject. 'How We Lost the War in Viet Nam' by Nguyen Cao Ky.
    – user3847
    Commented Aug 23, 2015 at 23:56

10 Answers 10

  1. First of all, to clarify what you asked in the subject, the US didn't "lose" the Vietnam war militarily. The Tet Offensive was basically a disaster for the Viet Cong and the forces of North Vietnam – they didn't achieve their intended strategic objective (popular uprising in the south) and suffered major losses.

  2. However, the US populace lost the will to fight in that war - as noted by others, they started viewing the war as "not worth fighting" (rightly or wrongly). The USA being a democratic republic, fighting a war that the majority of the people oppose and which has no geopolitical significance is not something those in power can realistically bother with.

  3. North Vietnam was also being heavily militarily helped by the USSR (not sure about China), and that did NOT stop when the USA went home

  4. There was a significant portion of populace in South Vietnam that wanted the North to win - they weren't "foreign" invaders, and the poorest parts of society are generally a lot less resistant to the idea of an ostensibly "we are for the poor" political forces taking over.

  5. Moreover, your quip at the end - while not exactly correct - has two grains of truth.

    • First, of all, dictatorships and totalitarian countries are a a lot less likely to care about significantly higher losses. Both from intrinsically lower value on human life, AND from far lower effect of losses on country's and military's morale.

    • Second, people with less to lose and less to live for are a lot more willing to risk death for some sort of cause on average.

  • 8
    +1. This is the most comprehensive and the most correct. Too bad US left. We missed you.
    – user4951
    Commented Dec 18, 2011 at 5:01
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    There were a number of comments on this question that were starting to get out of hand, so I deleted them. If you guys want to have an off topic conversation or discussion, please use the Chat room. If this continues I will have to lock the question and all responses. Commented Jun 6, 2012 at 13:58
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    +1 for part 4. The south was ruled by a horrible, unpopular dictatorship that didn't have the support of its own people. How effective is the army going to be if the soldiers hate they government they are fighting for? It is remarkable that South Vietnam held on as long as it did
    – gillonba
    Commented Aug 7, 2015 at 22:07
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    I like this guy's sentiment on totalitarian regimes and their value for huma life. That is why they did not care about losses, just the objectives, to kick America out of their country.
    – Dong Li
    Commented Apr 29, 2022 at 12:40
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    Points 1 and 2 don't add anything of historical relevance, it's basically the equivalent of "we could have won if we tried" which is a sour grapes conclusion, not a historical analysis. The US government repeatedly told their own people they would win, it just required some more soldiers. This became a pattern of broken promises, because the US military overestimated their capabilities, and could not achieve its strategic objectives. The answer ignores the Chinese nuclear elephant in the room, and how hideously corrupt Saigon was.
    – user17846
    Commented Jan 17, 2023 at 14:37

Up until Vietnam, the US had been training their military to fight a "conventional" war, more along the lines of what they fought in each of the World Wars. In Vietnam, the fighting was very "unconventional". In each WW, they could easily identify the enemy because they wore different uniforms and spoke a different language. In Vietnam, the enemy spoke a different language, but it was the same language as the military they were supporting. Furthermore, their enemy did not customarily wear uniforms. It was easy for them to melt into the surrounding populace without being clearly identifiable.

Another factor was the guerilla warfare. Much of the fighting in Vietnam involved night raids by the North, as well as surprise ambushes and quick assaults that melted away into nothing. What I mean by that is that the enemy would seem to disappear because they were so adept at blending into the landscape and they also made extensive use of tunnels to allow them to move troops and supplies. The US was ill equipped and poorly trained in how to fight a guerilla war.

When you look back in the history of the US, you could ask the same question about how the US was able to defeat the British during the Revolutionary war. The answer is basically the same. The US did not fight a "conventional" war, they were better able to make use of their surroundings and the terrain, and they fought a number of smaller skirmishes rather than trying to launch a full out attack against superior forces.

In both scenarios, there was definitely an advantage to fighting on your own soil. Your supplies are more easily replenished and it is easier to muster support from the rest of the country. In both cases, the home team just had to outlast the willingness and desire of the "invaders".

  • 22
    The same reason for 1776 war - but not because of guerrilla tactics. Most of the war of independance was fought as pitched battles between US+French troops vs UK+German troops. The reason the British lost was the same reason the US lost in Vietnam, it was very expensive to fight a war half a world away for a country that wasn't economically or politically worth the effort.
    – none
    Commented Dec 17, 2011 at 17:09
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    +1 . However, I didn't ask why US lost. I ask why south vietnam lost.
    – user4951
    Commented Dec 18, 2011 at 5:02
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    After all the US had done for south vietnam, they still lost.
    – user4951
    Commented Dec 18, 2011 at 5:03
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    There were a number of factors involved there. The inability of the US to maintain a successful military campaign as well as the efforts of the US to control the military initiatives. I believe a lot of South Vietnamese lost faith in their government because they felt that the governement had become puppets that were controlled by the US as a result. Commented Dec 18, 2011 at 5:28
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    @StevenDrennon not inability, unwillingness.
    – jwenting
    Commented Jun 5, 2013 at 5:29

The main reason was that the people just supported the North. The reasons may vary, but the South were considered a force fighting for the interests of the invaders and the North were simply liberators.

One of the previous answers notes that totalitarian governments can sustain higher losses. This does not do anything with the reality of Vietnam. How can you imagine a "totalitarian government" in a forest? In civil war usually wins the side which is more supported by the people, because people can easily defect and switch the sides, and no "totalitarian government" can do anything with it. The people in the North just loved their motherland while those from South loved their money.

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    -1 North Vietnam was a totalitarian government of the communist flavour. Currently, the Socialist Republic of Vietnam is a totalitarian communist government. Commented Jan 16, 2012 at 13:38
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    IMHO the first paragraph has the answer here. If (for whatever reason) the people of Vietnam had wanted the south to win, it would have. As they didn't, it really had no hope in the absence of a huge external presence.
    – T.E.D.
    Commented Feb 7, 2013 at 10:15
  • @Anixx from 11 years ago, you said "How can you imagine a "totalitarian government" in a forest?". I don't know whether the NVA had political commissars in its fighting units, but when the narrative is controlled at home by the government, the soldiers and populace will be indoctrinated to a large extent. Commented Jan 17, 2023 at 17:59

In my opinion, I think the only reason US+South Vietnam lost the war is due to the willingness of Southern people in the war. Vietnamese people have a long tradition of nationalism. They don't accept any invasion from outsiders. North Vietnam took advantage of this. They conducted propaganda to show that US was invading Vietnam and Vietnamese people had the duty to fight back.

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    And that's after the north vietnam mass murder many civilians? Stupid....
    – user4951
    Commented Jan 14, 2013 at 3:06
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    @JimThio You have to know that North communists were very good at propaganda and controlling information. The communists made people belived that those mass murder events were conducted by US and Southern Vietnam government. Even up till now, many Vietnamese students still believe in such propaganda.
    – reFORtEM
    Commented Aug 11, 2014 at 17:52

We lost the war in Vietnam because the American public no longer supported it. You can speculate on any number of reasons for this. People stopped believing the Domino Theory. Americans did not feel threatened by the Vietcong or North Vietnam.

It was part of the larger Cold War, but American public could not tolerate the death toll of Americans for purely ideological reasons. The South Vietnamese government was riddled with corruption with little real support from the South Vietnamese people. After years of claiming that they were winning the war, the Tet Offensive blew a huge hole in the American military's credibility. Even if Tet was a military defeat for the North Vietnamese, the American public did not see it that way.

In the end, the Vietnamese were far more willing to die for their country than we were willing to keep on killing them. They were, and are, a tremendously resilient people. Maybe it is better to speculate on why the Vietnamese communists won rather than why Americans lost.

Shortly after the end of the Vietnam War, the Vietnamese invaded Cambodia and stopped the genocidal slaughter there. They were really spurred on by the Soviets who didn't want the Chinese-supported Pol Pot regime to win. But it was also the right thing to do, and no one else would do it, including America.


In 1996, the North Vietnamese defense minister published an article in the Wall St. Journal about the moment when he felt that North Vietnam had won the war. It was when "Hanoi" Jane Fonda went to the North Vietnamese capital in 1972 to express her "solidarity" with them, returned home, and wasn't severely punished. Then the North Vietnamese felt that she basically spoke for the American people (who didn't want war). After the Americans finished pulling out later that year, the North Vietnamese redoubled their efforts (against the South Vietnamese only), and won.

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    +1 Jane Fonda. How can somebody be that cruel? Does she know how many people got slaughtered due to the war being lost? It's still not answering the question though. Even without the US, South Vietnam has about the same manpower, higher tech, and more industry. So how did they lose?
    – user4951
    Commented Dec 18, 2011 at 4:59
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    @JimThio Do you know how many people got slaughtered while the war was being fought? War, by definition is based on killing people to achieve your aims. The My Lai Massacre should give a good idea of what happens in a war.
    – apoorv020
    Commented Dec 18, 2011 at 7:51
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    @apoorv020 - Does war suck and people die? Yes. But it is evil and morally corrupt to equate killing of <500 people by <50 use soldiers - the ONLY such incident among 2.5 Million Americans who served in Vientnam - to atrocities committed by commies (From 1957 to 1973, the National Liberation Front assassinated 36,725 South Vietnamese and abducted another 58,499; that's not counting what happened after the war ended).
    – DVK
    Commented Dec 18, 2011 at 14:04
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    The Americans weren't supporting good against evil. They were just supporting one group of murderous bastards over another group of murderous bastards. The track record of the South Vietnamese shows that they would hardly have been more merciful had they been the victors, so an earlier end to the war at least spared a few war casualties.
    – lins314159
    Commented Dec 18, 2011 at 20:27
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    @lins314159 - have any sources confirming that assertion?
    – DVK
    Commented Dec 19, 2011 at 0:33

The short answer is that it was impossible for South Vietnam to win. The single biggest strategic issue was the People's Republic of China.

Successive American governments feared that if they invaded North Vietnam this would provoke Chinese intervention, just like in the Korean War. There was also a fear that this could escalate into war with the USSR.

In late 1964 the People's Republic of China tested their first atomic bomb: 596. By mid 1965 they had developed airborne delivery, and in 1966 the PRC was able to equip medium ranged missiles with nuclear warheads. The evidence is that Mao was not only willing to intervene in Vietnam, but was also preparing for it.. A combination of Maoist enthusiasm for intervention, and China's newfound atomic weapons, represented an exceptionally dangerous risk.

Consequently America was unable to defeat the regime in Hanoi, and so long as North Vietnam existed they would always work to overthrow the regime in Saigon. Officially America framed the war in the context of anti-Communism, but this was a fundamental error.

When Ho Chi Minh studied in Moscow his peers remarked that he was a nationalist first and a communist second. That was typical of the North Vietnamese mentality. It's understandable given history. Vietnam had been occupied by the French and Japanese, and it was believed that Saigon was just another puppet regime created by a colonial power.

South Vietnam's behaviour justified arguments against it. From the start the regime was plagued with blatant vote rigging, corruption, and institutional discrimination. The government was run by Vietnamese Catholics, who represented little more than 10% of South Vietnam's population. Promotion in the civil service and armed forces was often based on nepotism and religion; not merit. The South Vietnamese elite repeatedly provoked the vast majority of their own people, who were rural Buddhists.

All this led to the Buddhist Crisis, when peaceful protesters were shot dead by South Vietnamese soldiers. In response monks began to protest discrimination by burning themselves alive. This situation embarrassed America, and seemed to prove that the government in Saigon was indeed just another oppressive form of colonial minority rule.

America escalated their involvement in Vietnam out of fear. JFK and LBJ felt trapped by hysterical anti-Communism at home. At this point it was widely believed that America was losing the Cold War. Eastern Europe and China had fallen, and the Bay of Pigs had been a disaster.
In 1962 JFK remarked:

"If I tried to pull out completely now from Vietnam, we would have another Red scare on our hands."

In 1963 he said privately:

"We don't have a prayer of staying in Vietnam.... But I can't give up a piece of territory like that to the Communists and get the American people to reelect me."

As the war escalated so too did the body count. This was a way the White House attempted to prove they were winning. The argument went that there was a tipping point, after which North Vietnam could not replenish its losses and victory would be inevitable.

But this never happened. Instead civilian casualties became routine. Dead civilians were often tallied as Viet Cong, and American soldiers were sometimes told to assume anyone running away was a hostile target. There were many massacres by American soldiers. Most notably My Lai, where over 340 people, overwhelmingly women and children, were raped and murdered. More would have died had an American helicopter pilot not tried to stop it by landing between the Americans and the fleeing villagers. These incidents further eroded American credibility. When the war ended America had killed up to two million civilians.

By 1970 American morale was in free fall. War exhaustion was high. For years the American military had claimed it could win. It just required twenty thousand more soldiers... two hundred thousand more soldiers... another two hundred thousand soldiers. This pattern of repeated boasts and failures was becoming evident to most.

Even though the North's Tet Offensive in 1968 was a tactical failure with thousands dead on both sides, it shocked and unnerved the establishment. They were worried by Hanoi's ability to conduct such a massive operation so late in the war, and to still be able to keep going after it had failed.

Public opposition to the war and draft was common. Many Americans were angry that they and their friends and family were expected to die for an unwinnable war. There had been a spike in "fragging". American soldiers tried to kill their own officers, usually with hand grenades. There were over 360 such events recorded in 1971 alone, and that year the Armed Forces Journal declared:

“morale, discipline and battleworthiness of the U.S. Armed Forces are, with a few salient exceptions, lower and worse than at any time in this century and possibly in the history of the United States.”

In conclusion:

Ultimately South Vietnam fell because victory was strategically impossible given the threat of Chinese intervention.

South Vietnam repeatedly undermined itself with institutional corruption and discrimination. It failed to become a viable alternative to the North.

Consequently North Vietnam successfully presented itself as a means for the Vietnamese people to achieve national liberation.

American support for Saigon escalated due to the politics of fear and saving face, instead of a rational analysis of whether they could win or not.

The American presidency and military regularly boasted victory would happen sooner rather than later, and yet the war became the longest in US history. This led to the collapse of public and congressional support.

The threat of global communism was greatly exaggerated, as relations between communist states quickly deteriorated. By 1961 the PRC and USSR were publicly denouncing each other, and the PRC and North Vietnam regarded each other with contempt. Global communism would win the war, but it couldn't survive the peace.

  • Actually, given the long standing enmity between the Chinese and Vietnamese - there have been a couple of border clashes between the two since the end of the war, and China is currently trying to claim parts of the ocean that should be Vietnamese territory - that wasn't likely to happen. The major supporter of N Vietnam during the war wasn't China, it was the USSR.
    – tj1000
    Commented Oct 21, 2017 at 2:51
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    @tj1000 I completely agree with what you're saying. The reality was that communist unity began to fall apart relatively quickly. I don't think China's role in the region was motivated by love of the Vietnamese people, rather; if they got involved like in Korea it'd be a way to expand their influence. There may be an ideological element to that, where Mao wanted to push revolutionary conflict against America. But I couldn't source that at the time. Point being, China didn't need to be BFFs with Vietnam for them to be a principal strategic threat limiting US involvement.
    – user17846
    Commented Oct 21, 2017 at 11:29
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    I really like this answer. Thank you for the very accessible overview. It's really much better than other answers.
    – bonzo-lz
    Commented Mar 18, 2020 at 10:35

The answer as to why the United States lost The Vietnam War-(which actually was the Indochina War since it also involved the neighboring country of Cambodia), is rather complex and comprehensive in scope. Perhaps I can give AN answer, rather than a series of answers.

One main reason as to why the United States lost Vietnam, is perhaps we underestimated the strength and determination of the Communist North Vietnamese, initially led by Ho Chi Minh.

While Ho Chi Minh died in 1969-(approximately 4 years before the war ended), one must remember that he was the Supreme Leader of the Vietnamese anti-colonial resistance movement against the French Empire dating back to the 1940's. Ho Chi Minh mounted a consecutively aggressive campaign against the French and by 1954, the French withdrew from Vietnam. However, Vietnam, shortly thereafter, collapsed into Civil War pitting Communists-(largely supported by the Soviets and led by Ho Chi Minh) and Anti-Communists. The Vietnamese Civil war raged for 20 plus years, though during the first half of the Civil War, it was fought by the indigenous peoples largely without any visible foreign assistance-(on either side). However, by 1964, with the passage of The Gulf of Tonkin resolution, the United States officially allied itself with the Anti-Communist South Vietnamese and essentially, went to war, against the Communist North Vietnamese under the leadership of Ho Chi Minh.

The North Vietnamese fought their own version of trench warfare and guerilla warfare against the Americans, whereby snipers, land mines and various "traps" were scattered throughout the terrain. In addition to the North Vietnamese military, there was the Viet Cong-(a.k.a. the VC), who were often the ones who fought "in the trenches"-(so to speak) against the Americans and South Vietnamese. Keep in mind that this did not occur during the latter years of the Vietnam War, this happened pretty much from the start of the war and was authorized by Ho Chi Minh.

By the time of Ho Chi Minh's passing in 1969, the U.S. led Vietnam War was already 4-5 years old, Richard Nixon began a new-(or what appeared to be a new) policy towards Vietnam-(which eventually led to the expansion of the war into neighboring Cambodia), though it was becoming increasingly clear that the war-(especially after the disastrous Tet Offensive a year earlier).....was unwinnable. While Ho Chi Minh only fought against the United States for about 5 years, his strategies, tactics and mainly, his steadfastness, as well as his indefatigability, exhausted Americans on the battlefields, as well as Americans at home, while confounding and frustrating U.S. Policymakers in Washington-(who despite the exhaustion, perpetuated and even expanded the war for another 4 years).

The United States, in its 200 year history had "never lost a war".....until Vietnam....led by a seemingly inconsequential anti-colonial Communist Leader named, Ho Chi Minh. The underestimation of Ho Chi Minh's steadfast anti-colonialism and brutal warfare techniques, ultimately led to America's loss in Vietnam.

(And when Saigon officially fell to the North Vietnamese Communists in 1975, the city of Saigon was officially renamed....Ho Chi Minh City, which exists into the present-day).

  • Why the downvote? Please explain.
    – Alex
    Commented Jan 17, 2023 at 1:26

The only reason the south lost is because in April 30th 1975, they were already in sai gon fighting there last battle but they surrender because they did not want another event like Hue they still have the other marine regiment they could just call the marines that's still left out there back and take a last stand in sai gon but by that time if they do that then the vc had fire in to the city, killing civilians so that's why they surrendered it's because they did not want any more civilians to die

  • 3
    A better answer would have included sources.
    – MCW
    Commented Aug 10, 2014 at 12:19

How did the US/South Vietnam lose the Vietnam war?

The question really ought to be why was the US actually fighting a war in Vietnam. After all, they posed no direct threat to them, there being no land border with them - in fact, the land masses are separated by 12,000km!

Why they were there has to do with colonialism and racism; this was a right that was felt all across the Western world; for example, even the Nazis felt they had a right to territory required for their natural development - they called it Lebensraum.

But of course, the USA was not a small land-locked territory, by the time it engaged with the second world war it occupied half a continent and hence, one would think, had enough 'lebensraum'.

With the European powers occupied with rebuilding Europe after the two world wars, the USA felt it had to more or less hold the line against uppity colonial non-white subjects as well as put down communism - and this is why they were in Vietnam.

But the tide had turned against colonialism, the war that the USA was engaged in Vietnam, despite the compliance of the media, increasingly looked like the atrocities that the Nazis had carried out in Europe; thus the moral high ground that they had occupied after winning the war against the Nazis began to look increasingly shaky until, despite their overwhelming military force, they had lost the moral argument for waging war.

This is why Robert McNamara, the Secretary of Defense under both Kennedy and Johnson, and who played a major role in escalating the war against Vietnam, wrote in his 1995 memoir, In Retrospect:

"We were wrong, terribly wrong. We owe it to future generations to explain why."

The USA lost the Vietnam war because racially motivated colonialism was no longer acceptable in the West, and specifically in the USA, where a civil rights movement went from strength to strength.

  • 4
    This does not answer the question, and invokes Godwin's law.
    – MCW
    Commented Mar 16, 2020 at 21:30
  • @MarkC.Wallace: The question asked 'How did the US/South Vietnam lose the Vietnam war?'; I'm saying that they lost the moral argument for prosecuting such a war and this was felt globally; how is that not an answer? Commented Mar 16, 2020 at 21:33
  • @MarkC.Wallace The US was strongly anti-colonial in their rhetoric after WWI and WWII, how can someone then explain their involvement in Vietnam (and other post WWII in parts of the world which isnt in the Americas - the Monroe doctrine and its successors.) Commented Mar 17, 2020 at 14:14
  • @Stefan skoglund: The rhetoric wasn't matched up with deeds; this is after all what Bertrand Russell uncovered in his letters to the New York Times and then later picked up by the anti-Vietnam war brigade; he more or less accused the media to be in collusion with the government in covering up one of the most important stories of the last century ... Commented Mar 17, 2020 at 19:44
  • @StefanSkoglund: Moreover, I'd say that the US was anti-colonialist in rhetoric so as to not to portray themselves as colonialist Europe, but with the underlying agenda of roping in territories that the Europe was no longer able to control under their own hegemony; it's only when newspaper reports began to show the difference between the rhetoric and the reality that things began to change on the ground. Commented Mar 17, 2020 at 19:48

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