September 14, 2025

Fighting the Last War

During a recent podcast appearance, I took issue with the phrase "generals are always fighting the last war", and as the conversation moved on pretty quickly, I thought that the idea was worth expanding on.

To be clear, I am not claiming that military thought isn't profoundly shaped by the most recent available combat experience. It obviously is, although it's not uncommon to have the response be "everything involved in that was a horrible mistake and we should never do anything like it again". But the last general who actually thought the next war would be exactly the same as the last one died sometime in the 1880s, and since then the conversation has always been about how different the next war will be and in what ways. And in that environment, the main purpose of "fighting the last war" is to argue against a conservative1 take and for making more radical changes. And given that the discussion is happening, it doesn't really add any useful information beyond "unthinking and reflexive conservatism is wrong", which really should be obvious to everyone anyway.

More than that, I think the conservative view has generally held up pretty well. Obviously, things change, but those who prophecy immediate and radical change based on the new hotness of the day have not found their theories treated kindly by the test of battle. To take the easiest example to work through given my archive, the battleship was declared obsolete several times before it finally succumbed to changes in warfare. The first serious threat was the ram, which generally turned out to be a bigger threat to friendly ships than to enemy ones. Then there was the torpedo, which did prompt serious changes in how navies planned to use their ships and spawned a new type of vessel, but which didn't render battleships obsolete. Then it was the submarine, which again prompted changes and countermeasures, but which wasn't really a major threat to the battlefleet. And finally came the airplane, which did dethrone the battleship as the master of the waves, but which took several decades to do so and which left the battleship an important niche for another decade or so after that.


Billy Mitchell

The example of the battleship also illustrates another point: when making defense policy, what matters is not eventual rightness, but being right at the right time. Billy Mitchell, who claimed in 1920 that the airplane had already rendered the battleship obsolete, was entirely wrong, and had to rig his test on the matter. Whatever the eventual rightness of Michell's claims,2 a wholesale adoption of his views in 1920 would have been an obviously bad decision if war broke out in 1925. Likewise, even if, say, we will reach a point by the end of the century where unmanned aircraft have effectively replaced manned aircraft, it's probably going to be a few decades before we can build systems that we are comfortable setting loose to operate autonomously in an environment with the sort of limited communications that are likely to occur in a full-scale war.3 And until we know that such systems will actually work, it would be foolish to discard the manned aircraft entirely.

There's also a strong degree of selection bias in which incidents get remembered as "fighting the last war" and which don't. The obsolescence of the battleship gets a lot of play because it turned out that the critics were right in the end, and because the typical version of the story involves Pearl Harbor, one of the approximately three4 events from WWII that a typical American can remember. But what about the obsolescence of the surface ship in the face of the anti-ship missile? That one hasn't fared so well,5 and so the whole thing has been quietly forgotten, although I'm sure that if some future missile does render the surface ship obsolete, someone who said it was doomed in 1967 will be hailed as a prophet. And then there's stuff like the British 1957 Defence White Paper, which argued that the manned airplane was obsolescent in the face of the missile. This obviously didn't work out the way the authors thought it would, but they were far from alone in drawing that conclusion, and it's only something anyone remembers because it did tremendous damage to the British aviation industry.


A Global Hawk

Now, obviously the systems we use to fight wars will change, and new technologies will need advocates. But advocates are at their most convincing, and most worth listening to, when they are clear-eyed about both the benefits and limitations of their systems, and can provide specifics about how they work and where they fit into the existing systems. Someone who is going on about how drones will change everything and that we should cancel the F-35 immediately is likely to be operating in the mold of Billy Mitchell, particularly if they can't tell the difference between a Global Hawk, a Tomahawk and a T-Hawk. Someone who has put thought into the niches where unmanned systems do and, perhaps more importantly, don't fit is probably at least worth listening to.


A T-Hawk

It's also worth keeping in mind the stakes of getting things wrong here. We know that the old systems worked in the last war, and while the next war will be different somehow, it's also likely to be pretty closely related to whatever the last war was.6 Overly hasty embrace of the new in preference to adding elements of the new to a core of the old thus imperils everything. Or as a 1936 Parliamentary sub-committee said about proposals that Britain stop building battleships, “If their theories turn out well founded, we have wasted money; if ill founded, we would, in putting them to the test, have lost the Empire.”


1 Used in a non-political sense throughout, this is not a place to argue about politics.

3 And it's worth pointing out that even if recent advances in AI make you think this will happen much sooner than we would have thought 5 years ago, that's pretty short by the standards of military lifecycles.

4 The others are D-Day and one of The Bulge, Midway, and Iwo Jima.

5 To toot my own horn, I was on record predicting this back in 2018, so if, say, the Atlantic wants better defense coverage, it knows where to find me.

6 The last war globally, obviously, which is why every competent military follows relevant conflicts worldwide.

Comments

  1. September 14, 2025Basil Marte said...

    There are cases where for various reasons the adherents of the Yellow School (Jaune Ecole) keep re-proposing the same idea that had already been tested and found wanting.

    One example is transportation reformers' love of on-demand service, coming in waves since at least the '60s-'70s "personal rapid transit" ideas.

  2. September 14, 2025ike said...

    @Basil

    I am preety sure that you are thinking of the Young School rather than the Yellow School - though they are spell similarily in French.

    @bean

    The others are D-Day and one of The Bulge, Midway, and Iwo Jima

    Shouldn't there be an Enola Gay, and maybe a Fall of France in there too?

  3. September 15, 2025Doctorpat said...

    “If their theories turn out well founded, we have wasted money; if ill founded, we would, in putting them to the test, have lost the Empire.”

    Britain DID end up losing the empire, though it was not from lack of battleships.

  4. September 15, 2025bean said...

    Shouldn’t there be an Enola Gay, and maybe a Fall of France in there too?

    There's often some tension between my roles as purveyor of facts and teller of story. I try to limit my indulgences in the latter to cases when it isn't likely to get taken as actual fact and when it makes the writing significantly more fun to read.

  5. September 15, 2025hnau said...

    If anything I'd expect "three things" is generous. https://xkcd.com/2501/

  6. September 16, 2025Techanon said...

    There’s also a strong degree of selection bias in which incidents get remembered as “fighting the last war” and which don’t.

    You phrasing it that way immediately made me think of the most obvious example: guns.

    For all practical purposes, small arms are 150 year old technology, and there's not really any meaningful innovation in military rifles since like the 60s. Nobody ever looks at the army in 2020 and says "rifles? Pfft, that's your grandfather's weapon. Stop fighting the last war".

    Because there's a strong degree of selection bias in which things get remembered as 'fighting the last war'.

  7. September 17, 2025Hugh Fisher said...

    Speaking as a citizen in a western ally country that would depend heavily on US military help, and whose own military is guided by US doctrine and equipment, I'm all in favour of the US planning for a previous war. Specifically WW2, where the US would design something good enough and mass produce it. Can we do that again?

  8. September 17, 2025Anonymous said...

    The idea of fighting the last war may well have become so common that everyone competent in the military considers it a possible failure mode they have to guard against.

    Which may not have been the case in the past, remember that it is only relevantly recently in human history that technology begun changing fast enough for fighting like in the last war to lead to disaster.

    The best example that comes to mind for trying to fight the last war would probably be the fall of France in 1940.

    Techanon:

    For all practical purposes, small arms are 150 year old technology, and there's not really any meaningful innovation in military rifles since like the 60s. Nobody ever looks at the army in 2020 and says "rifles? Pfft, that's your grandfather's weapon. Stop fighting the last war".

    Since 1944 really.

  9. September 19, 2025StupidBro said...

    @Anonymous

    I would say that fall of France was far more political problem, that military one. After WW1 there was completely crazy peacefull movement (in something simillar to current far-right and far-left in the West) in the UK and France. French military would probably build far different army, if it was on them.

  10. September 19, 2025Anonymous said...

    But what type of Army France had in 1940 was on the military.

    The crazy peaceful movement didn't actually have all that much impact and less in France than the UK which had a channel separating it from the peninsula.

    Though I will grant that appeasement was a case of fighting the last war, in that case the war against Ireland.

  11. September 19, 2025StupidBro said...

    @Anonymous

    André Maginot lobbied the Maginot line against the wishes of French army. And in France (as same as in the UK) it was a political suicide to do anything for offensive war.

    You need to understand, that French government basically all the interwar period fighted the French army and cuted their budget. Because, to be fair, French politician rightfully thought, that sooner, or later the military would seize the power. In interwar period, average duration of a government was 7 months and it was unsustainable.

  12. September 20, 2025bean said...

    France in 1940 is complicated, although on balance I would say that it was one of the better cases for "fighting the last war", but also less than most people understand. French policy in the interwar years was profoundly shaped by WWI, but the French did attempt to keep pace with the updates. They were just far behind the Germans in understanding how mechanization could fundamentally change the pace of warfare, and expected things would be on a much slower cadence then they actually were.

    As for how the French army ended up so messed up, that was largely downstream of interwar French politics, which were absurdly terrible. I'm currently reading through Alistair Horne's To Lose a Battle, and it's been rather eye-opening on the sort of mess France had gotten itself into.

  13. September 21, 2025Doctorpat said...

    I was just watching the latest Forgotten Weapons episode on youtube, and Ian was arguing that the USA just adopting the M7 rifle was very much a case of "fighting the last war". Namely, that every war fought since 1914 has shown that infantry small-arm fire is exchanged at distances of 2-300m distance at most. And so, using a rifle optimized to give effective ranges of 3 to 5 times that merely results in weapons that are too heavy, with more training required to use effectively, not suitable for full auto fire, and where you can only carry half as many rounds of ammunition. So, eventually, every country gave up on the "full power" riles and moved to much smaller and lighter weapons using calibres like 5.56mm eg. the M16. And the result was lighter, easier to carry, and more effective at the distances that actual fighting takes place. BUT THEN... the USA has one war where shooting occurs at long distances (Afghanistan) and "hey, everything is different now" and they threw over a century of experience out the window to adopt a new rifle optimized for Afghan type 1000m shooting. Literally designed for fighting the last war. Meanwhile, in Ukraine, we can see that all the fighting is at near submachine gun distances of 100m or so.

  14. September 21, 2025hypozomata said...

    The French did understand the potential of motorization and created a dozen motorized/light mechanized divisions before the krauts had their first panzer division ready. What did them in was a failure to invest in sufficiently responsive command & control, a poorly developed air force that couldn't scale up force generation as well as göring's boys or generate enough sorties on the decisive few days, and pursuing an operational deployment plan that did not allow for a sufficient reserve.

  15. September 21, 2025StupidBro said...

    @hypozomata

    It is really not about that French army did not want to, it was really about that French government did not want to. French government just want as weak army as possible, either because they: a) were afraid of military overthrowing them, b) did wanted Communists could conquer them, c) did wanted Nazis could conquer them, d) were complete idealistic pacifistic lunatics.

    One minister of Air force was someone who supported occupation of France... So how you think it was plausible to make modern Air force?

    It is simillar to current state of France, only by magnitude worst.

  16. September 21, 2025Anonymous said...

    DoctorPat:

    I was just watching the latest Forgotten Weapons episode on youtube, and Ian was arguing that the USA just adopting the M7 rifle was very much a case of "fighting the last war".

    Never mind that the 7 mm British could reach those ranges with a more streamlined bullet and be usable at full auto (and it is still a capability worth having if you can get it without compromising the rest).

    Will the M7 be viewed as every bit the failure of the M14? Be surprised if it doesn't.

    hypozomata:

    What did them in was a failure to invest in sufficiently responsive command & control

    Yes, which was enough to make their advantages in equipment irrelevant.

    But why did they not make the effort to get workable command and control? That was because army command insisted that the next war would be much the same as the last one just with bigger tanks and faster planes.

    But WWII turned out not to be the trench warfare in Belgium that the French expected (that anyone pointing out otherwise would have their carrier ended also played a role).

    hypozomata:

    a poorly developed air force that couldn't scale up force generation as well as göring's boys or generate enough sorties on the decisive few days

    OTOH they had help from the RAF, if they'd demonstrated better command and control the British would have been more willing to let them borrow an air force.

    StupidBro:

    c) did wanted Nazis could conquer them

    Do you have any evidence of this?

    Certainly some military leaders collaborated after France lost but do you have any evidence that any of them actually wanted that to happen instead of just viewing collaboration as the least worst thing they could do in a bad situation?

  17. September 21, 2025Doctorpat said...

    @Anonymous

    "... viewing collaboration as the least worst thing they could do in a bad situation?"

    And how much of THAT was "fighting the last war" because being occupied by the Germans in 1914 really wasn't that bad, as much of France found out first hand. But things had changed.

    "Never mind that the 7 mm British could reach those ranges with a more streamlined bullet and be usable at full auto"

    Let's not get into a discussion on this, before I bring out my pet theory of .17 Remmington Fireball assault rifles...

  18. September 21, 2025Anonymous said...

    Doctorpat:

    And how much of THAT was "fighting the last war" because being occupied by the Germans in 1914 really wasn't that bad, as much of France found out first hand. But things had changed.

    From a personal point of view the allies beating Germany and liberating France was what made things bad for collaborators, without that they wouldn't have thought all that much had changed from the last war.

    Doctorpat:

    Let's not get into a discussion on this, before I bring out my pet theory of .17 Remmington Fireball assault rifles...

    It seems like nothing less than 6 mm (maybe 6.5 mm) is truly viable for infantry rifles that can be used everywhere (and nothing more than 7 mm).

    Which does rule out everything in service.

    That said 4.4 mm guns would have very low recoil. What about the .14-222?

  19. September 22, 2025Blackshoe said...

    I have no doubt that someone is using increased range as a bonus of the M7, but to be clear, that wasn't the main reason why they've decided to go up in caliber (it's to counteract the ubiquity of body armor).

    On WW2: one of the fascinating things about WW2 is how everyone really did a good job in the interwar years of looking at the last war and saying "Right, let's never let that happen again"...and they did! WW2 was fought very different than WW1. Whether the solutions they came up with were good or not, different question (looking at you, pre-war US Army tank employment doctrine). But they did a great job of avoiding the Western front again.

  20. September 22, 2025Blackshoe said...

    @Hugh Fisher:

    Specifically WW2, where the US would design something good enough...Can we do that again?

    Yes

    and mass produce it

    Ahahahahahahahahahahaha no, no we can't, that's impossible. Anyway, good luck to everyone out there!

  21. September 22, 2025StupidBro said...

    @Blackshoe

    "On WW2: one of the fascinating things about WW2 is how everyone really did a good job in the interwar years of looking at the last war and saying “Right, let’s never let that happen again”..."

    In my thing about WW2 is that it was completely unlogical war made by pacifists. And it kinda beautifully proves that extremely important things in human history can happen without some big reason, only because someone crazy seize power (is elected).

    WW1 had many reasons to happen but WW2 did not have any. Modern historians are trying to make them (most popular bullshit is how big reparations made Germany into fascism), but reality is that if Germany just executed Hitler after the coup, WW2 would never happen. Any sane government would attacked Germany immediately after remilitarization of rhine. If French government would had not fought with their military whole interwar period the war would probably be won in less than a year.

    Long story short, in my opinion WW2 was just caused by democracy and mainly voters yelling "Let's never let that happen again." and that makes it so much different from other wars.

  22. September 22, 2025Anonymous said...

    Blackshoe:

    I have no doubt that someone is using increased range as a bonus of the M7, but to be clear, that wasn't the main reason why they've decided to go up in caliber (it's to counteract the ubiquity of body armor).

    Then make the bullets out of DU or W (or even switch to flechettes).

    Alternatively invent power armor then you can switch to 20 mm.

    StupidBro:

    In my thing about WW2 is that it was completely unlogical war made by pacifists.

    No, it was fascist leaders of Germany, Italy and Japan.

    StupidBro:

    And it kinda beautifully proves that extremely important things in human history can happen without some big reason, only because someone crazy seize power (is elected).

    Yes, sometimes random things can have big effects.

    StupidBro:

    most popular bullshit is how big reparations made Germany into fascism

    It wasn't just reparations, but also the Great Depression which hit Germany very hard.

    With the economy doing well crazies (which included the commies as well as the Nazis) did nice and badly at elections.

    StupidBro:

    but reality is that if Germany just executed Hitler after the coup, WW2 would never happen.

    Possible and the law did not allow the lenient penalty he got.

    OTOH Japan was still going to rampage across the Pacific though Mussolini may not have thought Italy powerful enough to start a non-colonial war without an alliance with Germany.

    There's also the Soviet Union, but Stalin purged that to impotency.

    StupidBro:

    Any sane government would attacked Germany immediately after remilitarization of rhine.

    Easily too given that the soldiers sent to re-militarize it were unarmed, using childrens' toys as transport and under orders not to resist if another military decides to detain them.

    But there was also a view that the terms were unfair and that it should be returned to Germany.

    StupidBro:

    Long story short, in my opinion WW2 was just caused by democracy and mainly voters yelling "Let's never let that happen again." and that makes it so much different from other wars.

    I think it would be more accurate to say that it was caused by a mismatch between democracy and dictatorship, specifically an appeasement trap.

    But don't confine yourself to Europe.

    Also the voters weren't completely wrong about not wanting another War, WWI was so destructive that the French felt like it hadn't been worth it despite getting basically all their pre-war aims. Maybe why the French were willing to re-fight it, it had indeed worked and whilst expensive they were willing to pay that cost to prevent being invaded and it was something they knew how to do.

  23. September 24, 2025Blackshoe said...

    Anonymous:

    Then make the bullets out of DU or W (or even switch to flechettes).

    "Let's change our entire ammunition supply system to make it more difficult to manufacture and also make it so that some of our lowest ASVAB scoring members will require specialized training and extra PPE (having seen CIWS Uploads in progress, I can only imagine the fun of getting PV2 Joe to use all that stuff correctly) to use!"

    Power armor is always one of those things that I suspect will one day happen, but some magic needs to happen in energy production/storage first and I have no clue what that energy thingy is.

  24. September 25, 2025John Schilling said...

    We started making 5.56mm bullets with tungsten penetrators in the 1980s. They're not standard issue, but they're available if they're needed. But they don't automagically penetrate whatever armor the enemy is wearing because "Tungsten penetrates armor!!!". Neither does DU, which really doesn't give much better penetration than W.

    The Army seems to believe that, even with tungsten penetrators, 5.56mm NATO will not be adequate against next-generation body armor. They feel that 6.8x51mm tungsten penetrators are the practical minimum. I'm not sure they are wrong, and they do have more relevant information at hand than any of us here.

  25. September 25, 2025bean said...

    Power armor is always one of those things that I suspect will one day happen, but some magic needs to happen in energy production/storage first and I have no clue what that energy thingy is.

    I am skeptical of that. The problem is that to be infantry, the guy in powered armor needs to be able to climb stairs, and at current armor/bullet weight ratios, the amount of armor required to protect a guy is more than most stairs in the US can handle, to say nothing of Iraq or the like. And that was before people started to do things like the M7.

  26. September 26, 2025Doctorpat said...

    at current armor/bullet weight ratios, the amount of armor required to protect a guy ...

    Hence the need to develop active protection at the human scale. Using continuous ultrasonic sensors to detect any high velocity object.

    Which is why only a slow blade could penetrate the shield.

  27. September 28, 2025Anonymous said...

    John Schilling:

    They feel that 6.8x51mm tungsten penetrators are the practical minimum. I'm not sure they are wrong, and they do have more relevant information at hand than any of us here.

    OTOH the US Army did insist on not using an intermediate round before for no good reason so maybe they are doing it again.

  28. September 29, 2025Mateusz Konieczny said...

    In my thing about WW2 is that it was completely unlogical war made by pacifists.

    (...)

    Long story short, in my opinion WW2 was just caused by democracy and mainly voters yelling “Let’s never let that happen again.” and that makes it so much different from other wars.

    Are you seriously claiming that Russia and Japan was democracy at that time? Or have you missed their participation in igniting WWII?

    Reminds me about Open Thread 181 - are you again doing thing where you make false statements and later claim that it was hyperbole and you meant something completely different?

  29. October 01, 2025Ski206 said...

    I really feel like we are seeing a lot of this “fight the last war” syndrome with drones and Ukraine. There is little doubt that drones are a potential game changing technology. But to listen to some defense analysts (especially TWZ) the6a re essentially now the coin of the realm. They are arguing that the US should be stockpiling thousands of Shaheed like drones right now. All while ignoring that these supposed next generation weapons when employed by Iran against Israel for example have largely been failures.

    That’s not to say that we should not be moving at a high rate of speed when it comes to defenses against these weapons. The cost exchange of shooting SM-2 or AIM-120 or even AIM-9 at cheap drones is atrocious. We need the rapidly develop our ability to kill drones cheaply and rapidly. But stockpiling thousands of cheap drones as TWZ advocates that might well be obsolete and near useless in 6 months is not the way to go.

  30. October 02, 2025StupidBro said...

    @Mateusz Konieczny

    Sorry, I was talking about war in Europe, I would say that war in Pacific was more like war of two emerging powers over their sphere of influence. And I think that war would happend no matter what, only Japan want to exploite that Brittish are busy in Europe.

    And from Soviet perpective Germany starting to attack everyone around was never a bad thing. It only kinda got out of hands (54 million hands, to be exact). And to be fair, geopolitically Soviet Union was the biggest winner of WW2. The US would be major world power no matter what, Soviet Union would be, without WW2, regional European power.

  31. October 02, 2025StupidBro said...

    @Ski206

    I would say that drones became AI of military. It is definitely usefull and maybe a future, but that hype is sometimes really stupid.

  32. October 05, 2025Anonymous said...

    Ski206:

    All while ignoring that these supposed next generation weapons when employed by Iran against Israel for example have largely been failures.

    OTOH those have been largely for show, not total war.

  33. October 13, 2025quanticle said...

    @Techanon

    Nobody ever looks at the army in 2020 and says “rifles? Pfft, that’s your grandfather’s weapon. Stop fighting the last war”.

    I don't know about the Army in 2020, but in, say, 1950? People absolutely did say that. The US Army has a long and sordid history of attempting to replace the standard infantry rifle with something more "sophisticated". Whether we're talking about the flechette launchers of SPIW, or the grenade launchers of the OICW, the post-World War 2 Army has repeatedly sought to replace the "obsolete" repeating rifle with something allegedly better.

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