I'm not talking about world-ending, global-scale thermonuclear war, nor about massive salvos of missiles being fired at countries by other countries. I'm talking about, say, a few divisional-level ground-combat armored forces with a contemporary or near-future tech level throwing a bunch of Davy Crockett-style weapons at one another without it escalating into a full-scale nuclear war.

My question: why would they limit themselves to weapons on this scale, rather than simply escalating into a world-ending conflict? Is such a thing realistic?

Keeping this open and unanswered for a while to see as many perspectives as possible.

  • $\begingroup$ It depends in the first place of who is fighting whom. How would a war between India and Pakistan escalate into a world ending conflict? What exact superpowers care enough about India or Pakistan to risk triggering a world engulfing blaze? $\endgroup$
    – AlexP
    Jul 27 at 4:44
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    $\begingroup$ You should read the books "Arms and Influence" and "The Strategy of Conflict" both by Thomas C. Schelling. Limited nuclear war may be be possible - for example if during a Soviet invasion of France, France used nuclear weapons only on its own territory. Fortunately, nobody's tested this 'maybe' and found out for sure. $\endgroup$
    – mjt
    Jul 27 at 15:02
  • $\begingroup$ And if you want to read the cold war thinking on this question, the search term you want is "limited nuclear war" $\endgroup$
    – mjt
    Jul 27 at 15:04
  • $\begingroup$ Is this a "real world" in which ballistic missiles and long range bombers are flying just fine, or a different world with possibly different physics? $\endgroup$
    – Alexander
    Jul 27 at 17:26
  • $\begingroup$ @Alexander Real world. $\endgroup$
    Jul 27 at 17:38

The use of small nukes is already common.

If many wars and nations have already been using small nuclear weapons without escalation, then our world's fear of escalation is demonstrably unfounded in your world.

Perhaps many nations have an agreement limiting the size of weapons that they use, reserving their big exterminators as a deterrent against the big war that never quite comes.

Or perhaps the maximum size of nuke in common use has been determined by other means, like an International Criminal Court case, or the fiat of a major nearby power.


Why doesn't every war escalate to full-scale world war?

As long as nations realize that the nukes are merely being used as tactical weapons and not as attacks on them, there is no reason to treat the use of nukes as different from any other weapon. That is, the heavier the weapon used, the more seriously other nations would take the war, and the more warily they would treat the combatants, but they wouldn't jump to battle merely because nukes were used.

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    $\begingroup$ I concur with this answer. A tactical nuke used against an advancing army (e.g. NATO's Fulda Gap scenario during the 1980s) is an attack against a valid military target and therefore "acceptable". Contrast that with a strategic nuke used against a city, which is unacceptable because it kills noncombatant civilians en masse. $\endgroup$ Jul 27 at 0:53
  • $\begingroup$ This isn't to say that first use of even tactical nukes wouldn't result in sanctions from friendly nations. $\endgroup$
    – jdunlop
    Jul 27 at 23:25
  • $\begingroup$ Any number of things could result in sanctions. Down to and including sending in troops without firing a shot because a location is undefended. $\endgroup$
    – Mary
    Jul 28 at 0:56
  1. They can't escalate because nukes cant fly.


The Strategic Defense Initiative (SDI), nicknamed the "Star Wars program", was a proposed missile defense system intended to protect the United States from attack by ballistic strategic nuclear weapons (intercontinental ballistic missiles and submarine-launched ballistic missiles). The concept was announced on March 23, 1983 by President Ronald Reagan,[1] a vocal critic of the doctrine of mutually assured destruction (MAD), which he described as a "suicide pact". Reagan called upon American scientists and engineers to develop a system that would render nuclear weapons obsolete.

In this world the SDI system takes out rockets suspected of carrying nuclear weapons. Only small weapons like grenades and artillery shells can slip by the eyes in the sky.

2. Small nukes are what they have.


Tactical nuclear weapon: Israel may also have 175 mm and 203 mm self-propelled artillery pieces, capable of firing nuclear shells. There are three battalions of the 175 mm artillery (36 tubes), reportedly with 108 nuclear shells and more for the 203mm tubes. If true, these low yield, tactical nuclear artillery rounds could reach at least 40 kilometres (25 miles), while by some sources it is possible that the range was extended to 72 km (45 mi) during the 1990s. ...

Nuclear land mine: Israel supposedly has deployed multiple defensive nuclear land mines in the Golan Heights.

A small country fighting in close quarters with its neighbors might not want to nuke everything up. They have got to live there afterwards. Also a small country with a limited amount of nuclear material might see practicality in not putting all of its eggs in one basket. Spreading the nuclear resources among many smaller nuclear devices improved the odds of at least one being useful - as opposed one one huge bomb that is intercepted and that never goes off.


NATO defence of Europe was based on the use of Tactical nuclear weapons.

The Soviet land forces in Europe were larger in number and had more tanks, and there wasn't a good defensive line between the Soviet-occupied "iron curtain" and the "free west". It was believed that a simple mass advance by Soviet forces would overrun Western Europe.

It was possible that Western Europe could have maintained sufficient war footing to make this unlikely, but instead they chose to sit behind a tactical nuclear shield. The plan was simple; if the Soviets advanced, NATO would drop nukes on the advancing forces along bottle necks, such as the Fulda gap, using nuclear artillery or other weapons.

And if that didn't work, to escalate up to strategic nuclear use.

A Tactical response, using a similar sized weapon, would probably occur. Including press releases and diplomatic messaging that this is not an escalation, that the weapon was used Tactically against a military target, and that the yield was similar. If the original nuke used was about a 20 ktonne one (with some uncertainty), the response might be a 15 ktonne one, and the diplomatic and press releases might state that "it was a proportional response under 25 ktonnes".

While this would be dangerous, it could easily lead to a series of such weapon use, each time "under 25 ktonnes". Each side might then seek to not escalate beyond that line in the sand, because if they did, the other side would as well.

Something similar happened with strategic nuclear brickmanship in the cold war. The Tsar bomba had its yield dialed back to avoid a yield race; it was set off bigger than the biggest American bomb, but a large percent smaller than it could be, simply to avoid further escalation.

After the first few bombs, there would be a known convention that use of under 25 ktonne (or whatever) yield tactical nukes is acceptable in warfare if used against military targets. And both sides would be somewhat reluctant to break that rule; both sides might stretch it (firing 4 25 ktonne nukes in one MIRV? Is that 100 ktonnes or not?), and eventually you might get a treaty between two warring nations.

It would help if the war was not an existential one; ie, neither side is in danger of ceasing to exist. So a proxy war where the locals had a limited number of small nuclear weapons (like Cuba, or even parts of Europe) and escalated.


Without an external reason for why missiles don't exist, this is unrealistic

No tactical nuclear weapon has ever been used in a combat situation. (Source)

The only reason to not use strategic nuclear weapons is because you want a "surgical" conflict, you want to preserve something. This has a simple name:


Leon Trotsky once made a very practical observation:

There are no absolute rules of conduct, either in peace or war.

A war is fought either to gain something or to stop another from gaining something. The question remains, what is a nation willing to risk to gain that something, or stop another from gaining that something?

So far, the world has been willing to not risk everything. But our single data point, our own history, suggests that there is a limit. That limit is the step into tactical nuclear weapons.

Hollywood sometimes sucks

Hollywood is in the business of selling a cheap fix. Quick entertainment. And so they need to present fundamentally broad ideas in very short periods of time. Consequently, Hollywood makes it seem like tactical nukes basically don't exist — that the step into nuclear war is a whole lot shorter than it really is.

Maybe Hollywood's right, but it's probably not. With the exception of lunatics,1 the world has proven in all but two cases2 that it will not take that step to strategic nuclear war without a whole lot of something happening first. Oh, we'll posture and cast the proverbial vulgar hand gesture at one another — test a few nukes in out-of-the-way places to prove we have them — but we won't actually pull the trigger.

But we've never seen what nations will do if someone pulls a tactical trigger.

Tactical nuclear warfare is the trigger for strategic nuclear warfare

I can't think of any reason why anyone would roll out strategic nuclear forces during a conventional war. I'm not even sure I'd believe a story that presented it as a last-ditch effort to win an already lost conventional war. That doesn't reflect the subconscious fear the world feels about nuclear weapons. Likewise, I can't think of a reason why any country capable of a strategic nuclear response would hesitate to use it if faced with a tactical nuclear attack. Why?

Because the doofus is willing to use nukes at all

And your only option is to stop him dead in his tracks before he lobs even one more shell.

Having lived through the cold war, the Cuban missile crisis, and a number of other doomsday clock events, I can tell you that one of the greatest reasons no one would dare use tactical nukes is that the rest of us.. all of the rest of us... are scared to death of it.

So, what conditions might allow tactical but not strategic nuclear warfare?

  1. The "target" does not have strategic nuclear capabilities and isn't important enough for those who have strategic nuclear abilities to stand up and fight back in their name.

  2. Enough time has passed on your world that everyone who remembers the nuclear testing, use of nuclear weapons, and any cold-war-like conditions that threatened nuclear strikes, and at least one full generation beyond that, are dead. (In real life this might, maybe, happen somewhere between 2080-2100.) No one really remembers just how bad the consequences or even the fear were, leaving the world stupid enough to think that a tactical attack really wouldn't be that bad.3

  3. A nation develops what it sincerely believes is tactical nuclear protection for their military, opening the door to the idea of a "safe" tactical nuclear war.

Note: I can't actually imagine a world with artillery but not rocketry — but that's what you'd need to have tactical nuclear capabilities but not strategic capabilities. I consider this incapable of attaining suspension of disbelief, but that's just my opinion. But, I do have one more idea...

  1. Zugzwang. It's a chess term that describes a point in the game when neither player can make a move without significantly degrading their defense. Tactical nukes might be believable if you set up your story with a condition where neither military can make any move without basically giving up the war. Their only option is to use tactical nukes and hope like crazy the other guy won't respond with strategic nukes. This would actually make a fabulous story (I mean it, a Hollywood-options-paying-for-your-grandkids-college kind of fabulous), if you can seriously and believably set up the zugzwang. In this case, it's a race when the two combatants realize the zugzwang is forming, realizing they can't avoid it, and rolling out the tac-nukes first. You can believe the PEOC discussion would cause heart attacks all the way over in Tibet.

1By "lunatics" I mean religious fanatics, terrorists, heartbroken nuclear scientists... you know, anybody who has access to a weapon of mass destruction but doesn't have the common sense to not actually use it.

2Nagasaki & Hiroshima....

3If you'll forgive the momentary descent into politics, here in the U.S. we're experiencing a resurgence of Socialism despite decades of world experience with Communism. But we've begun to forget what pure Socialism and Communism can make of a society. You may agree with me or not at your leisure, maybe I'm wrong, but my point is that it's simple to do something stupid once enough people have forgotten how stupid it is. Very few people seriously study history, which is why it's a suspension-of-disbelief-worthy justification for the use of tactical nukes.

  • 1
    $\begingroup$ My situation is the first one: neither party (both warlord states) have serious strategic capabilities, and are not interested in antagonizing other nations, but they have a whole lot of tactical nukes (think .02-to-1-kiloton affairs launched out of artillery or on artillery-style rockets), they've undergone a regional civilizational collapse, they're both within artillery range - and they both hate one another. $\endgroup$
    Jul 27 at 1:18
  • $\begingroup$ During the Cold War, tactical nuclear weapons were something both NATO and the Eastern Bloc actively deployed and planned on using if war broke out, e.g. quora.com/… so saying that it's unrealistic isn't accurate. The threat of escalation from tactical to strategic nuclear warfare was recognized at the time but, as I have said elsewhere, striking a valid military target is considered legitimate where striking a civilian population is not. $\endgroup$ Jul 27 at 2:49
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    $\begingroup$ @KEY_ABRADE Re: antagonizing other nations, even tactical nukes release fallout into the air that will travel globally, antagonizing literally everybody else on the planet and inviting swift and harsh military intervention by a UN coalition. If your scenario allows introduction of future tech, make the warheads into en.wikipedia.org/wiki/Pure_fusion_weapon instead to avoid this issue. $\endgroup$ Jul 27 at 2:55
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    $\begingroup$ Arguments about escalation to strategic weapons depend on a near-universal belief that nukes represent a difference in kind, not in degree. That belief holds in our world, but your world may have a different path of development. $\endgroup$
    – Mark Wood
    Jul 27 at 17:30
  • $\begingroup$ @MarkWood That's my solution #2. I'm not convinced any nation could get to the use of tactical nuclear weapons without passing through the trauma of nuclear testing. That would have to be a delicately-written story. $\endgroup$ Jul 27 at 20:33

So, a major thing that would allow a power to use tactical nukes but not strategic nukes could be international public opinion, specifically in which tactical nukes are tolerated but strategic nukes would provoke a response. Since there is no historical precedent for this, you could just make your own up.

For instance, let’s take a hypothetical war between Country A and Country B (in which they both have tactical nukes, but no strategic nukes). By random chance, some Country A Lieutenant trapped in a hopeless position gets his hands on a Davy Crockett and decides to go for broke, using it on the enemy. Country B gets pissed and reacts in kind, causing Country A to start using them regularly, and so on. The International Community kinda freezes and decides they don’t want any part of that, and let it slide; but issue an ultimatum that if strategic nukes are used, the full weight of the world will fall upon whoever used them.

If you’re dealing with a war between full-fledged great powers that would normally be the ones applying pressure onto the nations doing the nuking, you could simply insert the previous, smaller war into the lore before your story takes place. After the war, they redraw up the treaties, which are sorta hazy on tactical nukes but adamant that strategic nukes are not to be used. When your Great Power Conflict breaks out, those great powers will be likely to use tactical nukes for their own advantage, but still avoid strategic nukes since they’d have SOME semblance of a guarantee that their enemy won’t either; and since no one WANTS to start a strategic nuclear war due to M.A.D., they could conceivably stay away from strategic nukes entirely, just so long as their opponent does to.

Tl;dr: tactical nukes get normalized but strategic nukes don’t.

  • 1
    $\begingroup$ It can be argued that the whole point of strategic nukes is to be so powerful that no one wants to see them used. One can argue that it follows from this that the only way to improve a practical nuke is to make it smaller, not bigger. Present such arguments as back-story. $\endgroup$
    – Mark Wood
    Jul 27 at 17:19

It's not realistic.

Nuclear weapons are weapons that have powerful political impacts, sometimes well beyond their destructive power. Your question didn't ask for political impacts, but I'm going to talk about them anyway because they might be more important than the military of sociological impacts.

You may use a Davy Crocket-type weapon to wipe out an enemy battalion, but you just created the enemy's best propaganda and recruiting material. The dead battalion becomes a unit of celebrated martyrs and heroes, and you will be portrayed as a sub-human bloodthirsty monster.

Historically, most wars end with a negotiated settlement. Nuclear weapons reduce an enemy's willingness to settle (who negotiates with sub-human bloodthirsty monsters?) and encourage retaliatory escalation (it's only fair, after all).

Escalation doesn't need to be in the size of weapon. Escalation could mean using more weapons. Escalation could mean using different weapons (chemical, biological). Escalation could mean a wider choice of targets (cultural sites, non-combatants, press). Escalation could mean a change of policy (from a limited goal up the spectrum all the way to genocide).

And escalation is easy if they did it first.

Once you uncork the genie of escalation, you no longer get to decide the path it takes you upon. The enemy gets a vote. Both populations get a vote. The wider community of peer states get a vote. Your domestic political opponents get a vote. Maybe you go down in history as the conquering hero...or maybe the fool who led their people to oblivion. It will take extraordinary leadership to weather the storm and calm the unleashed forces.

Now look at the non-escalation case: By NOT escalating, you deny almost all those parties a chance to overthrow you. Your remaining risk is losing the war (but you can settle before that occurs). Your personal risk is much lower...and you might still win the war anyway.

  • $\begingroup$ Let's say that these divisional-level forces, while still capable of full resupply and repair, don't need to worry about politics, due to a set of rather complicated circumstances. What then? $\endgroup$
    Jul 27 at 0:11
  • $\begingroup$ That's unrealistic. And the whole point is that you cannot predict the political repercussions of escalation. That's why it's a risk. Maybe you get lucky. Maybe you don't. $\endgroup$
    – user535733
    Jul 27 at 0:18
  • $\begingroup$ In the case of what I'm writing, the forces in question are sitting on top of massive arsenals and caches of machinery left behind by a fractured, collapsed, highly-factionalized country after a localized apocalyptic event. Each is led by a general who hates the other one, and both sides are highly socially and politically opposed to the other. I don't really think it's that unrealistic in this context. $\endgroup$
    Jul 27 at 0:24
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    $\begingroup$ A major nuke-user might find themself the target of a consortium. Entire units might mutiny rather than needlessly die of radiation poisoning. A subordinate might assassinate their seemingly-insane or foolhardy warlord. A secret underground of pro-peace saboteurs might grow among the junior officers of many forces. Those are all political repercussions that might occur in such a situation. $\endgroup$
    – user535733
    Jul 27 at 0:32
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    $\begingroup$ @KerrAvon2055 It's way worse than a sample size of 1. The USA propaganda has always mantained that they used their atomic bombs on Japan to force it to surrender, and they worked (Japan surrendered because of the atomic bombings). There's ample evidence to sustain a different opinion about that. And social awareness about the implications of nuclear weapons were not understood in 1945. Just 6 years after, the USA thought about using them in Korea, and didn't dare despite being the only nuclear power at the time (the URSS wouldn't test its first atomic bomb in 1953). $\endgroup$
    – Rekesoft
    Jul 27 at 7:54

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