The USA stayed in Vietnam from 1955 to 1975 = 19 years. They also stayed in Afghanistan for 17 years. Arguably, they failed to achieve their objectives on both occasions.

Why didn't the USA use nuclear bombs in Vietnam or Afghanistan to win the wars?

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    I’m voting to close this question because it is more a History question than a political question concerning Vietnam. And it makes no sense in Afghanistan due to dispersal of Taliban assets. Jul 15 '21 at 17:36
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    There may be a number of interpretations or nuances to take away from the first two occasions, but I'm pretty sure none of those should elicit a "hey, why don't do this more often?"
    – Will
    Jul 16 '21 at 5:18
  • @ItalianPhilosophers4Monica I'd say it's at least in part political because the decision which weapons to use in Vietnam was made at White House level and the decision to use nuclear weapons has ALWAYS been a political decision rather than a purely military one
    – jwenting
    Jul 16 '21 at 5:29
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    @jwenting this decision while political in 1967-1970 belongs strictly in SE.History 50 years later, where it has already been asked and answered. I had already commented to that effect, except that I had linked to my own answer rather than the question by mistake. Jul 16 '21 at 15:08
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    @Gary2 nope, no war crime but a sensible military decision that ended up saving hundreds of thousands if not millions of lives when compared to an invasion of the home islands.
    – jwenting
    Jul 19 '21 at 7:23

Nuclear weapons are both extreme and extremely imprecise.

In the case of Vietnam, while the 'nuclear triad' of technologies that most people associate with the Mutually Assured Destruction doctrine of the 60s and onwards was not yet available, the foundation of MAD was laid down by Secretary of State John Foster Dulles in the year before the U.S. presence in Vietnam began. The doctrine he outlined was known as "massive retaliation."

Nuclear weapons were therefore already understood as a world-ending weapon. Only to be deployed when the United States' very existence was threatened or already forfeit. Their presence as an existential threat was understood to be the thing that kept the Soviet Union from directly dominating the globe.

To use them in Vietnam, aside from the indiscriminate toll on civilian populations and ecological havoc that this would have wrought, would also signal to the world that the United States was willing to nuke anyone, any time, any where. This would, in turn, trigger the necessity for any nation that felt threatened by the United States to seek pre-emptive military action to protect themselves from nuclear attack. In other words, the Soviet Union would then have no choice but to deploy its full nuclear arsenal against the United States in the hopes of crippling the U.S. nuclear force before it could be used against Soviet territories or interests.

The first person to drop a nuke post 1950, ends the world. That's reason enough to not use the weapon.

As to Afghanistan, which is a post Cold War conflict so presumably not subject to the same political concerns, the nature of the conflict there was important. The war in Afghanistan was (not incorrectly) approached as a counter insurgency campaign.

The U.S. Counterinsurgency Field Manual, Chapter 7, paragraph 6, lays out one of the most important parts of counterinsurgency operations:

The more successful the counterinsurgency is, the less force can be used, and the more risk must be taken.

Followed by 7-8:

Some of the best weapons for counterinsurgents do not shoot.

Nuclear weapons are the extreme opposite of what counterinsurgency operations are about, and deploying nuclear weapons against a terrorist organization within a compromised host nation - inducing millions of civilian casualties to knock out a handful of extremists - would readily galvanize the entire Islamic world against the United States - and not without cause, either.

Nuclear weapons are primarily 'second strike' weapons. They're used as a threat, not as a realistic tactical or strategic option. The long tail on their effects means the costs of using them go on long after you've done so.

Overall, the U.S. Military began to move away from maximum firepower weapons and towards precision munitions as the nature of warfare changed, for this reason.

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    "To use them in Vietnam... would also signal to the world that the United States was willing to nuke anyone, any time, any where" - that seems like an odd conclusion to draw. Nuking a non-nuclear state that is incapable of retaliation does not indicate that the US would be willing to nuke a nuclear state like the Soviet Union and risk its very existence. This reasoning ignores the entire rationale of nuclear deterrence - whether or not to use nukes changes drastically whether or not your target also has them. Jul 15 '21 at 16:00
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    @NuclearHoagie Post Cold War, I would agree with you. But remember that Vietnam was a proxy war in the same way that the Russian invasion of Afghanistan was. Nuclear-armed interests were in play and being opposed by the U.S. action. Jul 15 '21 at 16:02
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    Supposedly triggers for use also included attacks on countries under the "nuclear umbrella" of the US. Not entriely altruistic, the US could either defend western Europe and Japan or wait until the Commies took them and added them to their strength. Regarding usability, you should stress more how interspersed the units were. The US would have to evacuate and then nuke, and having evacuated it would look pointless.
    – o.m.
    Jul 15 '21 at 16:08
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    @o.m. I had to decide where to cut for length. The way I see it, if nuclear weapons were ever considered a realistic option, then the force deployments wouldn't have been what they were. That they were incompatible with nuclear weapon use is a co-effect, not a cause in my view. Jul 15 '21 at 16:17
  • @nucl But the vietcong would surely retaliate with nukes. Of Russian or Chinese make. Result being each side splattered and the land inhospitable. Jul 16 '21 at 10:05

Neglecting moral and ethical issues, nuclear weapons would not have been effective (believe it or not).


Those conclusions were eye-opening. Although a RAND Corporation study estimated that one tactical nuclear weapon equaled twelve conventional bombing attacks, the JASONs concluded that an all-nuclear “rolling thunder”–style bombing campaign would require 3000 tactical nukes a year. Not even the massive U.S. nuclear production complex could support that kind of use.

Even with such awesome firepower, the results looked unsatisfying. Wargames played under Big War conditions—massed troop and armor concentrations in Europe—indicated that each nuke would only kill one hundred soldiers. Attacks against small, dispersed forces moving under jungle cover looked even less effective.

Mountain passes along the Ho Chi Minh Trail could be shut down and large areas of forest blown down by tactical nukes very effectively, but only until the Vietnamese cleared new paths. Maintaining damage and radiation levels would require repeated nuclear attacks and as one JASON said, "a tree only falls once."

Tactical nukes could destroy tunnel systems, but required precise targeting. If targeting were that precise why not just use conventional B-52 strikes? Said former CIA analyst Daniel Ellsberg, "If you don't have a target for B-52s, you don’t have a target for nuclears."

The Vietnam war was especially risky for tactical nuke deployment, since it could provoke the Soviet Union and/or China to respond. If they had armed the North Vietnamese with tactical nukes, then these nukes would have been exceptionally effective against the US forces.

If weapons comparable to the Honest John battlefield missile or the Davy Crockett nuclear bazooka made it into Viet Cong hands the results would have been catastrophic. "If about 100 weapons of 10-KT yield each could be delivered from base parameters onto all 70 [US] target areas in a coordinated strike," wrote the JASONs, "the U.S. fighting capability in Vietnam would be essentially annihilated [emphasis added]."

(same source as above)

These apply to the Vietnam war, but I'd be surprised if they don't apply to Afghanistan as well.


The United States encountered a multitude of problems in both conflicts. Lack of indiscriminate firepower was not one of them: They could have turned both countries into rubble with conventional weapons alone, but that was not the goal. Adding more indiscriminate firepower therefore would not have helped.

A more general analysis might even conclude that both conflicts, at their heart, were not military. Turning them into armed conflicts was the result of men reducing the complexity of reality so that it fits a mental framework they can, as men, presidents and generals, understand: A physical fight to determine who is stronger. That reduction was never adequate. The wars were consequently pointless to counter-productive, and "more war" in the shape of nuclear weapons would have been more pointless and counter-productive.

  • This answer seems to explain many of the interminable wars that have been going on the last few decades: military conflicts aren't the appropriate solution to ideological problems.
    – Barmar
    Jul 16 '21 at 22:25
  • @Barmar feel free to upvote ;-). Jul 16 '21 at 23:20

Nuclear bombs can easily cause genocides of millions of people, and the American administrations have been wary of normalizing genocides and the use of genocidal weapons. The same goes for chemical and biological weapons. They are too indiscriminately deadly.

It would green-light the use of atomic regional bombings by Russia and China in areas like Taiwan, Japan, Poland, Ukraine.

Vietnam was a cultural war: The Americans framed themselves as the enemy because they spent more money on destruction than food, supplies, aid, when they arrived in the country. Nuclear bombs would have worsened the war and caused regional and communist nations to retaliate against America, it would be inviting a nuclear world war.

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