Before getting into this note that I am NOT saying this would have been a good idea, nor am I advocating this as being a correct approach, not at all, it would surely have been horrific and very hard to justify, and likely counterproductive in many ways, but I'm asking this from a military point of view, in the interest of "winning" at war.

It seems the north would never abandon their goal to unite the country under communist rule. So the only way I could see to "win", to prevent the north from succeeding, would be to simply annihilate them. Otherwise you could stay there forever and not change a thing. It seems odd to be losing a war and yet not use your biggest weapon to turn the tide, to continue to lose troops and territory, yet restrain your military.

Did they not do it because they just didn't want to kill that many civilians?

Were they afraid the Soviets and Chinese would retaliate in kind?

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    All of those reasons. Ever heard of the Tsar bomba? :-) Commented Aug 2, 2019 at 5:06
  • 9
    Good question, but one of your premises ("It seems the north would never abandon their goal to unite the country under communist rule.") is pure hindsight. Responsible decision-makers of the time could have that as one of a whole family of possible NV positions, but could not possibly just assume it.
    – Mark Olson
    Commented Aug 2, 2019 at 12:32
  • 12
    If wars were just about obliterating the enemy, they would be easy to win. Imagine this: the American civil war. Britain comes and suggest to the North: "We got a super weapon which will wipe out the whole south and turn it into wasteland." Would Americans have said yes to this "help"? Commented Aug 2, 2019 at 22:48
  • 10
    Besides all the other answers, wouldn’t nukes have made it harder to keep insisting that we aren’t in a war?
    – WGroleau
    Commented Aug 3, 2019 at 4:54
  • 3
    The biggest misconception here is that you can win a war by military power. You can win battles with firepower, but you can't win a war that way. To win a war you need to win the people. Nuclear is a sure way to turn every allies in Vietnam into enemies, and to turn neutral parties and even some allies into your enemies as well. The US would have to be prepared to genocide the entire country if it dropped nuclear, and the US will likely crack with internal pressure because there are many people in the US itself that are heavily against that.
    – Lie Ryan
    Commented Aug 3, 2019 at 15:06

7 Answers 7


The US did not resort to using nuclear weapons in Vietnam for a variety of reasons: fear of the damage it would cause to the US's international reputation, domestic political considerations, a reluctance to break the 'tradition' of non-use, and a realization that, although there were plenty of viable targets such as airfields, ports and supply lines, only extensive use of nuclear weapons would be likely to have a decisive military impact.

Added to this was the strong opposition on moral grounds from key figures such as Secretary of Defense Robert McNamara, and President Johnson's concern at the long-term consequences of the use of such weapons.

A 1966 CIA Memorandum for the Director came out strongly against the use of nuclear weapons in Vietnam for a variety of reasons. Principle among these were that there

would be widespread and fundamental revulsion that the US had broken the 20-year taboo on the use of nuclear weapons.

Another section adds weight to the above point:

Their use in Vietnam, regardless of the circumstances, would send a wave of fear and anger through most of the informed world.

The report also mentions that there

would be intense agitation in Japan, probably leading to a restriction US use of Japanese facilities and possibly to denunciation of the US - Japan defense treaty...[and] a probably resolution of condemnation in the UN; and a marked diminution of such public support as US policy in Vietnam now has.

The report also says that the use of nuclear weapons might lead to a Chinese withdrawal but

we think it more likely that they would not do so

At the same time, though, the author(s) believed that the USSR would not use nuclear weapons or otherwise become directly involved. Instead, the Soviets would exploit the US action for propaganda purposes.

Among other possible or likely negative consequences, the report mentions

  • "NATO would be badly shaken"
  • European support would evaporate and the British government would fall if it did not condemn the US
  • the US would be the main target of calls to disarm while, at the same time, there would be nuclear proliferation because some countries would feel the need the acquire nuclear weapons.

There were other opinions, though. Tannenwald notes that, in a report in May 1967, the Joint Chiefs raised the possibility of using nuclear weapons in southern China, a prospect described by General Robert Ginsburgh in a September 1967 memo as "virtually unthinkable" when he was deputy to national security advisor Walt Rostow.

Less than a year later, the US commander in Vietnam, General William Westmoreland approved a planned contingency operation called Fracture Jaw which recommended the use of tactical nuclear weapons in January 1968:

Westmoreland cabled to Admiral Sharp a recommendation that the Commander in Chief, Pacific (CINCPAC), and MACV begin contingency planning for the use of tactical nuclear weapons in northern Quang Tri if necessary to prevent a major defeat. He noted that in the uninhabited mountains around Khe Sanh, such weapons could be used with great effect and with “negligible” civilian casualties.

When the White House found out, which it inevitably had to as only the President could approve the transfer of nuclear weapons to Vietnam, the plan was quickly shut down. In a memorandum to President Johnson, Defense Secretary Robert McNamara stated that the use of nuclear weapons was not an option

because of terrain and other conditions peculiar to our operations in South Vietnam, it is inconceivable that the use of nuclear weapons would be recommended there against either Viet Cong or North Vietnamese forces

Rumours of the proposed use of nuclear weapons had also become public by February 9th:

By that time...the issue had become public in the United States, with Senator Eugene McCarthy and others charging that the military was preparing to use nuclear weapons in South Vietnam. The administration, facing a domestic and foreign outcry, publicly disavowed any such intent.

Further, according to Tom Johnson who was then "a young special assistant to the president and note-taker at the meetings on the issue"

“When he [the President] learned that the planning had been set in motion, he was extraordinarily upset and forcefully sent word through Rostow, and I think directly to Westmoreland, to shut it down,”...

He said the president’s fear was “a wider war” in which the Chinese would enter the fray, as they had in Korea in 1950.

Johnson had already gone on record as being opposed to the use of nuclear weapons. In a speech on Labor Day 1964, he said:

For 19 peril-filled years no nation has loosed the atom against another. To do so now is a political decision of the highest order. And it would lead us down an uncertain path of blows and counterblows whose outcome none may know. No President of the United States can divest himself of the responsibility for such a decision.

Source: Chapter 6 in Nina Tannenwald, 'The Nuclear Taboo: The United States and the Non-Use of Nuclear Weapons Since 1945' (2008)

Johnson was, at the time, campaigning against the 'pro-use of nuclear weapons' Barry Goldwater but then United States Under Secretary of State McGeorge Bundy said LBJ's speech wasn't just politics:

Bundy wrote later that although there was politics in Johnson’s speech, there was “passionate conviction” as well. Two factors appeared to be key in Johnson’s thinking: the long-term effect of any use of the bomb “on the survival of man” – a prudential consideration – and the desire not to be the first president in twenty years to use nuclear weapons, that is, to break the powerful “tradition” of non-use that had now developed – a taboo consideration.

Source: Tannenwald

It wasn't just the people at the top of the administration such Johnson, Bundy and McNamara who were against the use of nuclear weapons:

Most scientists and civilian defense analysts involved in policy advising opposed use of nuclear weapons in Vietnam, for both military and moral reasons.

Source: Tannenwald

As an example of the above, see this March 1967 report Tactical Nuclear Weapons in Southeast Asia. One exception to this opposition was the physicist Samuel T. Cohen who, although defiant, wrote that:

anyone in the Pentagon who was caught thinking seriously of using nuclear weapons in this conflict would find his neck in the wringer in short order.

Source: Samuel Cohen, 'The Truth About the Neutron Bomb' (1983)

Tannenwald summarizes the decision to not use nuclear weapons in Vietnam thus:

Several considerations motivated non-use of nuclear weapons in Vietnam: the possibility of inadvertent and uncontrolled escalation with the consequences this entailed for US vulnerabilities, preservation of the tradition of non-use, and finally a taboo, a normative belief that using nuclear weapons would be wrong. For many US leaders, nuclear weapons were morally repugnant. To be militarily decisive, such weapons would probably have to have been used in large numbers, and this would have been politically and normatively unacceptable.

  • 11
    That "informed world" is rather frightening to read. It almost reads as if it would have been OK in a world where POTUS could have dismissed reports of nukes getting used as fake news. Commented Aug 2, 2019 at 16:58
  • 2
    That's quite a memo - this quote illustrates the question: "...And there would be some who would consider the United States foolish to accept defeat or even compromise in the Vietnam struggle without having recourse to its most formidable element of military power"
    – Duke Leto
    Commented Aug 3, 2019 at 1:49
  • 3
    What surprised me is that the report's dated 1966. First combat troops land in 65, IIRC. So, 1 year later already, nukes are already being considered. I would have expected 68 @ Khe Sanh. Or 69, post-Tet. Not 66. Glad the question was coolly evaluated and glad that LBJ had the clarity of thought to listen to his advisors. For precisely realpolitik, not sentimental, reasons, which history has proven right. I'll go along with @DenisdeBernardy on that one. Commented Aug 3, 2019 at 3:37
  • 4
    @Denis de Bernardy I could be wrong, but considering the pre-internet world being referred to, I thought it was more an acknowledgement that such news simply wouldn't reach certain parts of the world. Commented Aug 4, 2019 at 14:26
  • 2
    @suchiuomizu: no, it was almost certainly a reference to countries without state controlled news. Commented Aug 4, 2019 at 18:00

By the time of the Vietnam war, the US nuclear weapons policies had changed radically from the mid-1950s (when nuclear weapons were seen as the logical option for ALL conflicts), and were considered viable only as a last resort and as retaliatory weapons in case an enemy would use them (or other weapons of mass destruction) first against the USA or a NATO partner.

So nuclear weapons were not a militarily logical or politically acceptable option, even though no doubt some in the chain of command did draw up plans for their use had their use been authorised by the political leadership.

But given the politicians' demand for ever more surgical, low impact, strikes against ever smaller authorised target areas, that was never going to happen (at some point the white house was listing not just what enemy bases to target and avoid, but which individual gun emplacements could be hit, leaving US strike jets to have to fly through dense areas of SAM sites and AAA batteries to reach their targets while not being allowed to defend themselves or preemptively take out those sites because the WH was afraid there might be Soviet or Chinese troops manning them).

Without the political resolve in Washington to win the war in Vietnam the US military, which could have easily pulled that off without resorting to nuclear weapons and with the forces in theater during most of the Vietnam war, the war could never be won with any weapons. This seriously demoralised many in the US military btw.

  • Comments are not for extended discussion; this conversation has been moved to chat. Commented Aug 5, 2019 at 7:20
  • Unfortunately the link to the 1966 CIA Memorandum for the Director is broken, and I cannot seem to find this document anywhere now.
    – Duke Leto
    Commented Aug 26, 2021 at 4:21
  • 1
    @DukeLeto its rather late, but here's the fixed link. I've also suggested an edit to Lars's post to update it.
    – mbrig
    Commented Sep 27, 2022 at 2:56
  • Thanks, this question is very apt today!
    – Duke Leto
    Commented Oct 5, 2022 at 16:00

At that time, the US was concerned that a repeat of the Korean war could happen, with China sending in masses of troops... North Vietnam shares a border with China, just like North Korea. China wasn't overly fond of N Korea or Vietnam (in both cases, the initial supporter was the Soviet Union, not China), but when UN forces got near the Chinese border in N Kora, China sent in masses of troops... hundreds of thousands of troops.

So, defeating N Vietnam simply wasn't possible without risking Chinese intervention and massive loss of life on both sides. The whole Vietnam situation was a complete mess... in hindsight, it's hard to believe just how ill conceived it was, and how long it dragged on.

Also, the mid to late 1960's is when China and the Soviet Union had a major falling out, so it was difficult if not impossible to ascertain exactly what China would have done if N Vietnam were seriously threatened.

The use of nuclear arms so close to China's borders would have been extremely provocative: imagine China setting off nukes in Mexico. Unlike Korea in the 1950's, China had nuclear weapons in the late 1960's. Would they have used those weapons in response to the US using them so near their borders?

Best not to find out... an error of judgment could see Saigon wiped out, and all US personnel there.

Related note: the exit of the US from Vietnam closely parallels the unprecedented opening of diplomatic contacts with China, which had been essentially closed to the rest of the world at that time.

But, that's another very interesting story for another time.

  • 3
    The use of nuclear weapons against a communist adversary would have been provocative to the Soviet Union as well. A nuclear exchange with them would have been...very bad.
    – Seth R
    Commented Aug 2, 2019 at 14:30
  • Yeah, the Korean war was totally a proxy war with the USSR and China completely on-side with the DPRK. Nuclear retaliation from the Soviets was as serious a threat during the Korean war as it was with the Vietnam war. Surely the USSR would not have stood by and watched if the US had nuked Pyongyang.
    – J...
    Commented Aug 2, 2019 at 17:11

The ostensible war aim was to keep the South Vietnamese people free of communism so that they could thrive. Dropping nuclear bombs on their fellow countrymen in the North would have been self-defeating, even assuming that it worked at a military level and did not result in retaliation of any sort: (1) it's so close it would likely have contaminated South Vietnam with radioactive fallout; (2) it would have shown an immense level of contempt for the people the US was trying to help. A Vietnamese life wasn't worth less just because the person had the misfortune to be born in the North; it would have been unthinkable to compound that misfortune by dropping nuclear weapons on them. And I'm sure South Vietnamese hoped for reunification some day, just as West Germans did. You don't help people by slaughtering their brothers and cousins....

  • 9
    I think it's tragic irony that while this should be the right answer it probably isn't the real reason. The US supported ruthless dictators in South Vietnam (such as Ngo Dinh Diem), so much of the US strategy in Vietnam was self-defeating with respect to the goal of helping the Vietnamese people. Commented Aug 2, 2019 at 14:12
  • 6
    @CalebMauer Yes, but it would have been self-evidently self-defeating. US propaganda could well say, "dictator, what dictator? He's a totally Nice Guy!", but it couldn't say "nukes, what nukes?" Commented Aug 2, 2019 at 14:33
  • @John Coleman Thanks, you are quite right. I edited accordingly. It turns out memories from pre-school days (when the fighting was going on) about war aims aren't always trustworthy.
    – C Monsour
    Commented Aug 2, 2019 at 21:14

Bombing the dikes in North Vietnam was also considered. But it was abandoned as causing too many casualties.

At some point, you have to consider the international political fallout of winning a war at all cost. Killing 100k-1M civilians by rupturing dams would have been a PR disaster and would have seriously set back US efforts to contain Communism on the world stage.

Regardless of the amount of deaths, even if they are all enemy soldiers, using atomic weapons first will carry a massive stigma. You might somewhat get away with it if you are facing an existential threat to your country, say if Israel had done it in 1973, as some suspect they told the US they would do if losing. Or within Western Europe in the 70s or 80s in case of a massive Soviet invasion.

Done on a tactical level, the bomb wouldn't have had long term strategic (war-winning) impact. It was considered, I believe, at Khe Sanh, as the US didn't want Dien Ben Phu 2. But the political fallout would have been massive.

Done at a strategic level, ie. bombing of NV infrastructure, it might have worked, but the political cost would have been that much greater and escalation with the USSR could have been a possibility.

These insurgency wars are extremely hard to win in general and best avoided. As a big part of winning them is the elusive hearts and minds, excessive civilian casualties need to be avoided at all cost.

On a similar vein, B52 bombings in Cambodia severely damaged the US' image.

Not using nukes was the right call and precisely the reason why the ultimate war-waging authority needs to be held by politicians rather than left to the military. The US "lost and lived to fight another day" and Communism collapsed 20 years later. That might have turned out differently given a world that had massively rejected US values and alliances.


Probably also because the Non-Proliferation Treaty (NPT) was signed on 1968-07-01 and came into effect on 1970-03-051. It was negotiated during the 1950s and 1960s.

The signatory states of the treaty with nuclear weapons (and the USA is one of these) have made it clear that they will not use nuclear weapons against signatory states without nuclear weapons except in response to a nuclear attack, or a conventional attack in alliance with a Nuclear Weapons State.

So unless the USA wanted to throw the NPT into the dustbin and risk nuclear proliferation (and nobody wants that), they could not use nuclear weapons against North Vietnam (or Cambodia or Laos).

Note that we are normally talking about usage of nuclear weapons as actually detonating them. That's forbidden and nobody has done that since 1945. But of course they have been used by openly or covertly threatening their detonation. Daniel Ellsberg has reported in The Doomsday Machine that the USA did that on multiple occasions because it's policy on first use isn't as clear as one would hope.

1 When did the USA ratify the NPT?

  • 4
    Certainly no leader of the United States would ever throw a nuclear treaty into the dustbin and risk nuclear proliferation. Nobody wants that.
    – Davislor
    Commented Aug 2, 2019 at 22:39
  • 1
    @Davislor The problem with that logic is that the US constitution allows the electorate to appoint an imbecile as president, should they so wish.
    – alephzero
    Commented Aug 4, 2019 at 9:58
  • 1
    @alephzero: Never heard of sarcasm?
    – DaG
    Commented Aug 4, 2019 at 20:14
  • @Davislor the US threw the INF treaty out after the Russians had violated it deliberately and for years despite being asked to stop doing so. tit-for-tat.
    – jwenting
    Commented Aug 8, 2019 at 3:47

Question: Why didn't the United States resort to nuclear weapons in the Vietnam War.

Simply put that was one of the questions decided in the 1964 election where the conservative Barry Goldwater seemingly favored the use of nuclear weapons in Vietnam.

  • Goldwater said: "By one impulse act you could press a button and wipe out 300 million people before sundown."
  • Goldwater said: "Commanders in Vietnam already had the authority to use nuclear weapons and did not need a presidential authorization."
  • Goldwater also said: "I would remind you that extremism in the defense of liberty is no vice! And let me remind you also that moderation in the pursuit of justice is no virtue!"

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How Daisy Add Changed Everything about Political Advertising

The incumbent president Johnson capitalized on these statements by airing the famous Daisy Attack Add, Sept 7, 1964. The Johnston campaign aired it only once and was pulled from the airwaves it probable aired an additional 1000 times free of charge by the media, the Johnston campaign had no need to pay to run it again. Its shocking point was made. A vote for Goldwater was a vote for nuclear war.

Lyndon Baines Johnson went on to win the election by the widest majority since James Monroe's virtually uncontested second term election of 1820.

From the Comments

@Ed999 The Democrats won that election in '64 because their incumbent President had been assassinated 12 months earlier, not because of any perception that Barry Goldwater was pro nuclear war. Goldwater could have campaigned on any issues he cared to, or not, and nothing would have affected the outcome. That election turned solely on the issue of the assassination, and nothing was ever going to influence the result, whoever the Republican candidate had been or whatever policies the GOP had espoused.

That's a bit of an oversimplification and ignores President Johnson's incredible transformation and political astuteness which brought about his landslide victory in the 64 election. Johnson the son of a poor sharecropper from west Texas was a lifelong segregationist who was considered unelectable to national office because of his long history championing the policies of the South.
Johnson transformed himself into President Kennedy's torch bearer beginning the day after the assassination. In his first televised national address Johnson threw his whole weight and the emotional outpouring for the slain president behind the stalled 1964 Civil Rights Bill. Personally stewarding it through congress.
In championing a Kennedy signature initiative which Kennedy had been unable to pass through Congress himself, Johnson solidified himself with Kennedy's political machine, and the nation, and eliminated his greatest impediment to winning the Presidency on his own.
Yes, portraying Goldwater as out of touch and willing to use nuclear weapons in Vietnam went a long way to painting Goldwater as unelectable in the minds of the American voters. Both of these two action were about winning the Presidency and helped bond the morning nation to Johnson with the effect of the landslide victory in 1964.

  • 2
    The Democrats won that election in '64 because their incumbent President had been assassinated 12 months earlier, not because of any perception that Barry Goldwater was pro nuclear war. Goldwater could have campaigned on any issues he cared to, or not, and nothing would have affected the outcome. That election turned solely on the issue of the assassination, and nothing was ever going to influence the result, whoever the Republican candidate had been or whatever policies the GOP had espoused.
    – Ed999
    Commented Apr 25, 2020 at 21:58
  • 1
    @Ed999, If you think a life long segregationist from south texas was the natural successor for Camelot, then I think you are mistaken. Johnson sold himself to kennedy's machine as Kennedy's man, and he Sold Goldwater as out of touch. Both reflected political campaigns whcih were masterfully executed.
    – user27618
    Commented Apr 26, 2020 at 0:10

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