Shares of a division

Here's a quote form Dunnigan's old book "How to Make War" (2003, p. 124)  that - while old - still largely applies:

Depending on the type of division and nationality, infantry comprises 8-30 percent of division strength, tank crews 1-10 percent, and artillery (including antiaircraft and antitank weapons) 6-12 percent. Combat troops comprise an even smaller potion of non-divisional forces, something like 5-10 percent. Since combat divisions account for 20-50 percent of army manpower, combat troops comprise only 10-25 percent of all personnel. In all armies, combat support troops are very much the majority.

Elsewhere he wrote that infantry comprises about 5 percent of a Western army's personnel strength only.

There was a move away from division-centric to brigade-centric force structures since, but the overall picture remained about the same. Thus let's take Dunnigan's summary above as a basis for some thoughts:

Some support efforts have a fixed size (equivalent to fixed costs in economics); area air defence by a SAMP/T battery does not scale with the combat troops in the shielded area, except that it is either provided or not. Bridging requires about the same effort, regardless of whether one or ten tank battalions are going to cross that bridge. Load carrying capacity (MLC 60, MLC 80 etc.) doesn't affect personnel demands much either. The width of a bridged river on the other hand changes personnel requirements slightly (more pontoons = more lorries to carry them = more engineers for driving and installation). Electronic warfare is similar; either you have those jammers to blind a JSTARS-like aircraft 300 km away or you don't. Either you have the receivers in position to triangulate radios in the area or you don't - there's no proportionality with the quantity of combat troops in the area.

_ _ _ _ _

A look at tooth to tail ratio or a listing of percentages as Dunnigan provided implies a relationship between combat troops and combat support (fashionably: "sustainment") troops that's following a stable causality. Now I pointed out that sometimes the terrain features instead of the combat troops are the influencing variables. Long-time readers of D&F may probably sense where this is heading:

The 'book' needs to be rewritten and reconsidered for low force densities in state vs. state or alliance vs. alliance (a.k.a. "conventional") warfare.

A 100 x 100 km area may see (among other forces) five manoeuvre battalions, one area air defence battery, one independent bridging company, one field hospital with MedEvac helicopters, one battery with 100 km range artillery missiles and one jammer against radar aircraft.
What happens with the support elements if there's but one brigade in action in the area? Will there be the same amount of one-or-nothing support elements or none? Does this problem lead to an even smaller share of combat personnel in an army or to the opposite, a cutting down of combat (service) support of the one-or-nothing nature?

Second challenge; what about small allied powers' contributions? They do likely not (and should not) have the same assumed-to-be optimal structure in miniature. Shouldn't the larger armies with focus on collective defence compensate for this by having even more than optimal shares of support troops in order to reach the optimal mix in a collective deterrence and defence effort?

Another challenge; with only 10% combat troops an opposing force needs to cause less than 5% casualties to break all of our ground forces and to force them into a general retreat. Maybe 2% if the offensive is limited to one region. We sure need to have personnel reserves for the refreshing (refilling) of combat units, but (assuming these reserves are not in the support units) why wouldn't we employ these reserves right from the start if this leads to a less than proportional growth of support requirements, in low force density scenarios more pronounced than in a long time?

In the end I advocate a close look at the optimum mix for low force density scenarios, while keeping in mind that over time the arrival of reinforcements (even from different countries) will change the structure and the force density in the theatre of war - and thus also the optimum structure.

There's a pretty strong case for thorough research, experimentation and alliance-wide coordination in order to avoid wasteful spending and a waste of the soldiers' time with surplus capacities.




I wrote about skirt armour on wheeled vehicles recently, and casually mentioned the effect of CTIS (central tire inflation system) on tires. The system regulates the air pressure inside. At highest setting these tires are very hard and efficient for road travel, while at lowest setting they're really soft, unsuitable for high speeds but best for difficult (especially soft) ground:

Sorry for the poor quality, my cheap ancient digital camera had many settings wrong apparently.

The technology has been introduced many decades ago, the Soviet BTR-152 APC and ZIL-157 light lorry were as far as I know the first examples of quantity production vehicles with CTIS (compare this study). The BTR-152 likely had it in order to achieve similar offroad-performance as halftracks during WW2, at least in Central Europe.

It's exceedingly difficult to find photos of tires with CTIS in very low pressure mode on the internet. That's probably because it looks as if the tires are flat, and it's mostly unsuitable for presentation purposes. Here's an exception, in context from CTIS marketing or farming (where ground compaction due to high nominal ground pressure is a problem):

CTIS effect on Unimog
You can get improved offroad performance without going that extreme, of course. Still, the low pressure mode should be taken into account in regard to
- attempts to shield the tires (changing geometry)
- calculating ground pressure
- actual offroad ground clearance
- probability of sidewall punctures when sidewall touches the ground regularly
- suspension quality offroad (the tire as a "spring" can go a shorter distance, and has a different spring constant = slow driving is advisable)


P.S.: No comments on this topic because I'm tired of "tracks vs. wheels" debates.


It's more complicated than that

The (quite time-consuming) discussions in the comments of the last weeks have pointed something out to me that wasn't obvious (to me). I'm *sometimes* not good at anticipating such things because they're alien to me.

I wanted to use this GIF for a long time, and it makes the text a bit less bitter.

(1) The fascination of symmetry

There's no need to view things in symmetry all the time.
Back in antiquity archers didn't necessarily fight hostile archers more often than other troops. Cavalry didn't necessarily fight cavalry more often than other troops. Spearmen didn't necessarily fight spearmen more often than others.

Modern infantry shouldn't be compared to other modern infantry with a focus on infantry vs. infantry combat. Remember, in conventional warfare infantry gets killed >80% by artillery and mortars! Their main purpose is evidently NOT in shooting at other infantry.

Likewise, tanks won't be understood if one focuses on their ability to defeat other tanks. This kind of thinking has buggered IFVs more than any other category of tanks; they were even equipped with ATGMs at the expense of one dismount seat and at great risk of secondary fires or explosions inside the squad compartment. Later on during the 90's, frontal protection against 30mm AP(FS)DS became a strange focus, even though poor protection against shaped charges was the elephant in the room.

The art of war isn't about clashing same against same nearly as often as it is about being unfair or using rock-paper-scissors mechanics to advantage.

(2) The overemphasis on killing

I tried to convey this back when I wrote about tactical repertoires and functions in warfare, but evidently even among my readers the overemphasis on killing is terribly intact. The vast majority of troops doesn't kill in a year of even in the fiercest of conflicts, but they're still of great use usually. There's so much more that needs be done than mere killing and destruction. The typical military exercise with its ludicrously high attrition rates never teaches this, but almost everything that armies do is not about killing. The killing part is the tip of the iceberg. An army that neglects to pay attention to all those non-killing jobs will be a sucker at the killing part every single time.
Now most of us are not paid to devise the military of the future, but we're citizens who can vote and express opinions, also shape opinions - and we don't serve our society well if we perpetuate the overemphasis on killing.
An infantry company may very well be of extremely great use by overseeing and if need be blocking some forestry roads - this may together with similar such efforts restrict the movement of a mechanised force such that it runs into a trap. Said infantry company may have shot at and disabled some armoured recce vehicle on its route reconnaissance, but nevertheless it would be its presence and ability that shaped the battlefield and constitutes its utility, not the kill count.

It's typically not possible to win a campaign by artful manoeuvring alone, even though this would be great. The second best option is to win/end a campaign by artful tactics that make the advantageous outcome of all major combat events predictable. I think this is what we should strive for; develop forces and if need be use them in a way that achieves the political purpose without resorting to primitive attrition bets. Instead, we should determine outcomes of combat before the major combat occurs (which keeps friendly casualties low), and logically this requires excellence at the activities that are no about killing and destruction.

(3) Clarity of thought

9th grade and higher match classes include theory of sets, logic et cetera among all the formula stuff. Pupils and many parents don't have much respect for this seemingly arcane stuff, but I have grown a deep respect for its importance. Many people simply cannot think logically. Everybody gets carried away sooner or later, and nobody is good at discussions if his or her main motive is plain hostility.
Yet there's also a problem (and this is mostly from observations beyond this blog) with people simply not thinking logically. The conclusions drawn from such fuzzy thinking may be creative, but usually they're plain nonsense.

One example; the topic of an article was whether certain components in food are causing cancer or not. A commenter accused the author of some things I won't repeat here, and his only line of reasoning in support was that in other countries people don't even have enough food.
This was utterly irrelevant, of course. Other countries have other problems, their severity doesn't mean that we shouldn't address our smaller problems. No doubt his employer ceasing to pay him is not nearly as bad as people in Afghanistan dying to mines and duds, but I'm sure the commenter wouldn't feel that this was a good reason not to be bothered about the lack of pay.

Other examples are the very common 'misunderstandings' where comments assert that I am proposing or denying things when I did nothing of the sort. I clearly don't like to discuss against wild and unfounded interpretations of what I wrote for real. Feel free to pin me on whatever I wrote - no doubt sooner or later you can find some inconsistency, lacking evidence or falsifying evidence. There should be no need for wild (if not hostile) interpretations.

I look around the internet, I read newspapers, I listen to political discussions on TV (rarely) and what I see is a world full of people with flawed logic. Maybe I sound a bit Vulcanian here, but I think it's overdue that everyone begins to try hard to check his or her own writings for logical inconsistencies.



Cyber aggression

"A key requirement to determining if there is an armed conflict taking place would be the deliberate intervention of members of a state’s armed forces."

This is from a reply to a parliamentary question (and other parts of the reply may be of interest as well), and a likely unintentional admission of very far-reaching consequences:

Offensive "cyber" ('hacking') activities would rather be considered an act of war (armed conflict) if done by a (para-)military bureaucracy than by a civilian bureaucracy or mercenaries.
There are many reasons why armed bureaucracies trying to develop a 'cyber' arm look a lot like a typical bureaucracy trying to grow in power and size, but this one is in my opinion a knock-out to the idea of offensive 'cyber' capabilities in armed service.

You would simply get away with offensive actions more likely if you are known to not have such a (para-)military cyber arm. The armed services are systemically disadvantaged in this regard.

Let's assume our government or alliance definitely doesn't like how some other country of significance is run by a tyrant, and we want to tip the scales towards  an ousting as for example against Ceaușescu in Romania. A great or superpower backs this tyrant, though - and we don't want a much more intensified conflict with them. Maybe we could disrupt the censorship, reshuffle banks' funds towards dissenters, dig into bureaucracy files and expose/publish appalling corruption, maybe we would even want to distribute a call to every adult to go on strike the next day, or rise up. 
All of this would create much more backlash if the entire world knew that we had this capability in the armed services than if instead we merely employed mercenaries - many of which would probably not even live in our country or not even be fellow citizens.
This isn't even about the technical ability to trace malicious activity to a source; we know that eventually the usual suspects would be blamed quickly (see Stuxnet), but evidently it makes a great difference whether this source is a (para-)military bureaucracy or not.
This also means we would likely get less often falsely accused if we have no institutional, (para-)military ability for such offensive actions.



Skirt armour on wheeled AFVs

Civil wars tend to produce much DIY weaponry and even armoured vehicles, and Syria is no different. The Oryx blog recently showed some of the one-off 'designs' of the Kurds in Syria.

Quite striking next to all those slat armours and improvised rusty soft steel turrets were the skirts used to protect the tires of BTR-60 wheeled 8x8 APCs. The contraptions likely impeded steering in their specific implementation, but otherwise they may point at something important.

I suppose the emphasis on protecting the tires stems from the inability to replace busted tires. Even patching them is probably a major logistical headache.

Still, these skirts - if effective at all and I suppose they do at least defeat AK/RPK bullets - would also greatly improve the sustainment of mobility of wheeled AFVs. An AFV can keep going for a bout 80 km after having its wheels punctured due to the actually simple run flat technology but then there's a huge problem of supplying enough spare tires. Hardly any spare tires are carried in the units themselves.

Western land forces didn't seem to care much about this in the recent wars of occupation. To maintain mobility wasn't valued as highly as reducing casualties more directly, and armour was thus mostly designed to protect the men inside the vehicle, not to maintain its mobility. The threat of fragmentation and bullets was also overshadowed by blast mines and RPGs.

I suppose it would make sense to look at such skirt plates (or meshes) for the defeat of bullets and fragments for wheeled AFV types meant to be used in mobile warfare, including reconnaissance. 

I understand there's often a benefit of the doubt in favour of the armed bureaucracy's competence, thus I raise you the glory of wisdom known as the Cold War's Fuchs Transportpanzer design:

Fuchs Transportpanzer, (c) Anderle

A mere 7.62 mm machinegun (that cannot defeat any protected vehicle) as armament, without any kind of shield, much less a turret. As if it was a soft lorry. Whatever benefit of the doubt the bureaucracy might want to claim, it was squandered by historical precedents IMO.

So maybe let's use other peoples' lessons learned and have a close look at this detail. It may be pivotal for the utility of wheeled AFVs.



A call for a unified light infantry

Back during the Second World War infantry divisions defined the frontline during the less hectic phases; they did set up and maintain a string of pickets and positions that defined 'ours' and 'theirs'. These de facto divisions of the line made up about 85% of the German field army throughout WW2.
The other 15% were about 10 per cent points fast troops (armoured, mechanised, motorized or semi-motorized cavalry divisions) and about 5 per cent points specialised light infantry formations; mostly mountain troops, few dedicated Jäger divisions, and the Luftwaffe's true paratroopers (let's count them as army here). These figures were rules of thumb, not accurate - but descriptive enough for painting the overall picture.

Later, during the Cold War, West Germany promised a twelve division army for a planned 26 division defence in central Europe against the Warsaw Pact. Germany had rebuilt and recovered so quickly that by the mid-50's it had a higher economic output than ever before WW2, and motorization had progressed as well. The new army was almost fully motorized, and the infantry (Grenadier-) divisions were equipped much heavier than their ancestors - more like late WW2 American infantry division orders of battle (that had organic tank support).
Army structures were changed a couple times, infantry was renamed from "Grenadier-"* to "Jäger-", but what mattered the most was that both the more infantry-strong and the more tank-strong brigades were meant to establish and maintain a semblance of a front line with mobile warfare tactics. This had been done before, for example by a motorized division south of Stalingrad that covered a sector hundreds of kilometres wide (steppe terrain).
There were some mountain and paratroops brigades as well, not the least because they were supposed to be cheaper (not so much or at all if you consider the need for transport aircraft and helicopters). The old infantry division-centric idea of an army was gone, at least regarding peacetime order of battle.

Post-Cold War, the Jäger brigades went away as well, and even the occupation mission in Afghanistan and earlier similar peacekeeping missions in the former Yugoslavia did not change this: Jäger brigades used wheeled vehicles that were most suitable for such missions, were relatively cheap, had the infantry strength to 'put boots on the ground' - but they were not preferred. Save for Jäger leftovers on the battalion level, the only German infantry of the 2000's were para and mountain infantry.

This is a similar outcome to what happened in other NATO powers; 'regular' infantry demised, 'special' infantry (marines, mountain, para, heliborne, ranger) survived the cuts (and "special forces" were created), possibly due to higher prestige and higher perceived utility.
_ _ _ _ _

This begs the question; why differentiate at all? Why not go to a unified (light) infantry?
Let's compare the two most common infantry types; para and mountain
(a) both largely lack heavy weapons
(b) both are typically motorized, with lightly armoured wheeled vehicles at most
(c) both are typically expected to meet high physical fitness standards
(d) both are heliborne-capable
(e) both depend on light infantry tactics and little (if at all) on infantry-tank cooperation

The paras get some parachuting training, but you can get a more demanding (manual jumps) parachuting training on four weekends in a civilian parachuting school for a few hundred Euros. The mountain infantry gets (or is supposed to get) some high altitude training, usually with at least some serious mountain climbing training.
Yet it's neither realistic to expect a parachute assault larger than battalion nor is it realistic to expect more than a fraction of mountain troops to be of much use above 3,000 m altitude.
And there are lots of air defence systems and very few high mountains at the periphery of European NATO.

Furthermore, "brigades" imply an accomplished combined arms capability, whereas "regiments" admit a focus on one of the branches with little combined arms capability. A light infantry regiment could still have a regimental artillery battery or two rather than only infantry, and would still deserve to be called "regiment" more than "brigade".

I suppose we could and should garrison army unified light infantry forces close to mountain, swamp, settlement and woodland training areas. The size could vary from a two infantry battalion regiment to two regiments with each four infantry battalions. "Battalion" sizes may vary, so this may really be about 1,500 to 5,000 personnel.

One battalion with extra qualification in parachuting including a HAHO platoon of parachuting experts/trainers.
One battalion with extra qualification in high altitude combat including a platoon of mountaineering experts/trainers.
One battalion for combat support (two batteries which choose between 120 mm mortar and 105 mm howitzers as the French do, one company for electronic intelligence and joint forward observers.
One battalion for  non-combat support including a platoon which retains the super-rare skill of (combat) bridging at high altitude and a small company that maintains animal-handling skills (mules and llamas, forget the inferior Haflinger horses).

Bavaria has both some mountains and some swamps for training (assuming the latter could be used legally). Two unified light infantry (Jäger) regiments in Bavaria would make sense for Germany - particularly if they were allowed to train in Austria (EU ally) often. Their ease of long-range administrative marches in exclusively wheeled vehicles would allowed for frequent exercises with mechanised forces in low lands as well.
Other countries could unify their infantry as a versatile force for terrains where mechanised troops are inefficient or ineffective as well. (The reasoning changes if a country decides to mechanise its airborne forces in Soviet/Russian style.)


This may have had the appearance of some military history summary followed by an Order of Battle proposal.
It was really meant as something different; the regimental OoB example isn't important. I mean to point out that the current army structures with their infantry types are legacies** and neither optimal nor necessary. A force design released from the shackles of the past would almost certainly not arrive at what we have nowadays, but at a force structure that recognizes the small importance of the infantry specialisations and the great importance of the infantry's unique strengths vis-a-vis mechanised forces.

Also, please not I did not argue to unify all infantry forces. Mechanised infantry and my basic volunteer infantry proposal were not included. The separation between stand-alone "Jäger", "Gebirgsjäger" and "Fallschirmjäger" forces makes hardly any sense, though.




*: Grenadiers were elite troops from the 18th century that used hand grenades and early grenade launchers. The ordinary infantry had been renamed "Grenadier" or "Volksgrenadier" by the Nazis in mid-WW2 in an attempt to bolster their prestige and morale. "Jäger" were reliable light infantry with rifles instead of muskets during the 18th century, and with their open order tactics precedents for 20th century infantry. The term "Jäger" had not been used much by the Nazis, so it was more politically correct in West Germany and used to rename the regular infantry, while the "Panzergrenadiere" were never renamed.
**: Originally airborne forces were separate from mountain infantry because they were first introduced during the Nazi era and the head of aviation ministry and air force, Göring, wanted to be in control of airborne troops. The training and material needs of mountain and airborne troops were never very different. Airborne troops were often employed in gliders, which could have been done with mountain troops and their light equipment as well.


Finnish land forces doctrine

Here's a video about the "new" Finnish land warfare doctrine.

English subtitles can be activated!

Essentially they took what they already had ("Sissi" tradition, "Jäger" tradition), combined it with 1970's Spannocchi-style Raumverteidigung and (in my opinion an overdose of) trust in digital radio communications and encryption.

As you can see in this video, breaking contact, dispersion and elusiveness are very important (to them). 


Modern self-protection smoke; examples

I don't want to pass on these; a (marketing) brochure with nice images of smoke effect in visible and IR spectrum and lots of specs about delay time, spectrum coverage, munition weight.

Such munitions are for launchers as these, of which there aren't enough mounted on combat vehicles and usually none are mounted on non-combat vehicles. Reloading under armour is always impossible and such launchers are almost never bulletproofed, which they should be. I think this category is underrated for armoured vehicles, 'soft' vehicles and dismounted personnel.

Smoke is also very useful for protecting areas against PGMs; the only fallback option in face of a combination of successful radar jamming, SatNav jamming and multispectral smoke is to use either dumb or inertial navigation munitions. Smoke was already used to conceal industrial point targets back during the Second World War.

RP (red phosphorous) has WP (white phosphorous) as an intermediate product and is accordingly more expensive, as far as I know it's roughly twice as expensive. It is less troublesome and appears to be the agent of choice for multispectral (visible and IR) smoke agents, though some alternatives were tested and produced as well. RP smoke isn't affecting thermal sensors for long, though. The longer smoke durations require continued burning of additional material.



Some links on Baltic defence

Michael Kofman, War on the Rocks

Wesley Clark et al, ICDS

I disagree with so much of the latter, and often on such a fundamental level, that I feel no desire to pay any additional attention to it. Accordingly, I won't take it down piece by piece. A rare agreement of mine with the authors is this paragraph, though:

"Multi-nationality must be ensured in this kind of presence, but the cohesion and combat capability of the battalions must not be compromised as a result. The last thing we need is ineffective "Frankenstein”battalions. Therefore, each battalion should have a core nation."

It's giving a sense of satisfaction that the mainstream finally pays so much attention to the Baltic defence. I began to do so seriously in 2010 already, and IIRC wrote sometimes about it even earlier (though not here).
Professionals working full time on defence issues should or could have seen the problems a decade ago at the latest. Sadly, here we are and the issue was still not addressed satisfactorily.



It's the voids, stupid!

I'd like to summarise what I wrote about skirmishing, delay, pursuit, force densities, shaping ops, armoured recce and so on over the course of the years:*

The best practice in future conventional (government vs. government, gloves off) land warfare will be to seek superiority in the voids between the few concentrations of forces.

There will be battalion battlegroups and (small) brigades that don't disperse much and can be treated as classic manoeuvre elements. Yet the spacing between them will be dozens of kilometres (maybe 100+ km in some scenarios, see Ukraine), and what happens in these "voids" is what decides the campaign. For it's what decides about ammunition supply for the manoeuvre elements, decides about their practical mobility (how impeded it is), deters them from advancing or not, blinds or enlightens their commanders and potentially denies army aviation operations.

The major manoeuvre elements (battlegroups, brigades) could execute their classic manoeuvres well if and only if the events in the voids permit it. Clashes between brigades would have a predetermined result because the shaping ops that happened in the voids delivered the real decision. The few classic battle-like clashes of massed forces would shatter already-doomed forces that didn't escape in time, akin to the elimination of pockets in WW2.

The void spaces would be devoid of united and massed forces larger than companies, but those independently-manoeuvering armoured-recce and long range scout-like forces in platoon and company or even only squad (LRS) size would dominate the voids, supported by long-range assets (artillery, electronic long-range surveillance and nighttime helo medevac mostly).
Their campaign - the scouting, skirmishing and observation campaign detached from larger forces - would be the decisive one. The army that's superior in this facet of land warfare would be as dominant as back in WW2 the armies that better mastered rapid operations with tank-heavy formations.
The better main battle tank may thus be of little consequence compared to the better armoured recce car and the better ability to call in responsive long-range artillery fires.

That's the real departure from classic land warfare as Carl von Clausewitz  and other thinkers wrote about: They saw the decision in what mobile concentrations of great power would do, whereas in the future when a single sniper pair may doom a tank battalion with a radio call or two such concentrations of power should merely seal a deal that was already negotiated by the skirmishing forces.

Modern field manuals still follow the orthodox, classic patterns. They're either about the (small) unit level with little consideration for what their actions cause in the greater picture or they are about how to commit the force concentrations. They're not about (small) units shaping the battlefield with merely over-the-horizon support from force concentrations. The closest thing to this are probably the Jagdkampf tactic and Raumverteidigung doctrines. I'd rather emphasize this in the context of armoured reconnaissance forces, for well-armed combat-capable (instead of observation-focused) armoured recce is the closest to the needed skirmisher force for the voids.

The brigades meanwhile would be 'fleets in being' that contribute to the deterrence of opposing forces advances and serve as long-range support nodes to the skirmishers until committed to breaking an opposing peer formation (preferably in a pincer manoeuvre). They wouldn't need so much "Panzer" troops dash, but rather patience and long range arty. The highest demands would not be placed on the leaders of tank forces, but on the skirmishing armoured recce platoon and company leaders. That's what the 'best and brightest' officers should be assigned to. Meanwhile, nations with a rather cumbersome mechanised forces culture would merely need to improve on their evasion skills in order to avoid decisive engagements of their brigades until the shaping ops provided the right setting.

Nothing of this would prevent that actual generals would send actual brigades to clash with opposing brigades ASAP in a future conflict. Just as insights in the role of firepower didn't prevent the French army's suicidal offensive tactics in 1914, after all. I'm merely pointing out what I think will be best practices. It's not a prediction of actual future campaigns.


*: I'm too lazy to look up all the links. Simply click on the "Military theory" tag on the left if you want to look the stuff up.


"The U.S. Army’s War Over Russia"

edit 2023: This blog post aged fairly well, but its last part about towed artillery didn't. The Russian armed forces are so bad that even 155 mm L/39 M777 towed artillery survives in Ukrainian service for months on average.
by Mark Perry, POLITICO

That article has weaknesses (particularly the lines about tanks), but it nicely summarises an example of Niskanen's bureaucrat and the principal-agent problem in effect, two models that I've described and applied on D&F repeatedly:


The U.S. Army has a couple rock stars; two of them are mentioned in the article (MacGregor and McMaster). Honestly, I was never terribly impressed by their output. They're often referred to as intellectuals, smart and great thinkers and so on, but their published writings never seemed to be particularly impressive to me. 
MacGregor's signature book "Breaking the Phalanx" featured some nonsense (mostly about organic army aviation) and otherwise only unimpressive ordinary stuff. I was told that it was still a ground-breaking book in its context (U.S.Army) and that it broke with certain anachronisms specific to that armed service, but to me it looked not terribly different from what Europeans did in the 60's already.
So in addition to that principal-agent / bureaucratic behaviour thing, I'd also like to point out that we better not buy into descriptions of people as particularly bright ones. Form your own opinion based on their actual output!

It is noteworthy that the U.S.Army's complaints about being outgunned and outranged have at least some merit regarding tube artillery.
Yet this is of their own making. They failed spectacularly with their Crusader project, developing an SPG with little more performance than the PzH 2000, but multiple times its price per copy - and got it cancelled because of the excessive costs. Another attempt was to shoehorn a M109 replacement into the FCS boondoggle - but that, too, would have had no greater range than the M109. FCS was cancelled as well, and with it the SPG ("NLOS") version that offered almost no improvement over the M109.
So instead, the U.S.Army is using a M109 that's no M109 any more because every single part (hull, turret and gun) was replaced in some upgrade sometime during the M109's long time in service (with only fire control making much progress after the first very early gun upgrade). It's essentially a 3rd class SPG with an ordinary 39 cal. barrel, mediocre mobility (at least able to pass over weaker bridges than PzH 2000, though) and no particularly impressive rate of fire.
The U.S. Army's "outgunned and outranged" problem is even worse in its light and medium brigade types (Infantry BCT and Stryker BCT), for they use towed 155 mm howitzers (instead of M109 SPGs) which lack 360° traverse, are slow loading and feature a 39 cal. barrel as well. The U.S. airborne forces have essentially no artillery for use in conventional warfare and would thus be near-useless as reinforcements to the Baltic region, South Korea or Taiwan, for example. The USMC has the same inadequacy.
Yet again; these are shortcomings of their own making - the bureaucracies failed to replace equipment of the 1970's that was outperformed in the 1980's already. Often times they failed with successor projects or introduced overhyped yet obsolete-by-design systems (M777).



Syrian Civil War explained [censored]

This is a sanitised version of a rant from October 2015.

I'm getting increasingly "disappointed" by comments about the Syrian Civil War and by the Western military reactions.
Thus even though I don't think the Syrian Civil War is in any way related to the defence of my country or its allies*, I will write down an explanation. 
All of this could have been understood within the framework of 18th century art of war already.

First, Da'esh (also known as IS, ISIS, ISIL - I don't think they're a "state", though). Their success is explained by a single, simple fact: They possess strategic and operational mobility.
This is not a matter of motor vehicles. They would still possess superior mobility if they used camels only. This is NOT about hardware. Their mobility stems from their personnel structure. They have a mercenary army. Their mercs are not all in it for money, but they are - typical mercenary - not from the region, and this is all-important. A jihadist from Europe doesn't care whether he's being sent into a fight in Western Syria or in Eastern Syria - Da'esh can even send him into Iraq.

Meanwhile, the other civil war factions have always been or have devolved** into local militias or networks thereof. Their fighters typically expect to eat their mother's or wife's meals every day at home, and don't intend to fight in some part of Syria unknown to them or even inhabited by some other ethnic or religious group.
These militias cannot easily muster the troops concentration for an offensive, and the few times they did they failed, not the least due to lack of unity of command. Essentially, they can only fight at home or in other regions of their own group, whereas Da'esh can set up a Schwerpunkt and attack with local superiority at any front.

The Assad regime would have lost long ago had it not received support from some mercs as well - Hezbollah. Yet Hezbollah isn't really in this civil war to win all of Syria back for Assad - they're rather motivated to protect the Shi'ites from what would happen if the Sunni forces conquer Shi'ite territory or even all of Syria. So Hezbollah is not much of a mobile reserve for Assad, particularly not any more after they experienced severe casualties.

Now about the bombing campaign of Western powers and Arab autocrats:
What they're doing are strikes at intelligence-delivered targets and at targets of opportunity. They kill, maim and destroy. It's pointless, because all this does is it suppresses Da'esh temporarily and partially.
They cannot win through this campaign of attrition unless Da'esh makes a huge mistake itself. Da'esh can simply avoid defeat by keeping its exposure small enough to not lose more personnel and material to the bombing campaign and ground combat than they can replace. This isn't difficult because their opponents on the ground lack a good punch, as I explained above.
These generals employ air power not to "win", but to delay defeat - again. They did the same over Afghanistan already.

Now the Russians. It appears they bomb with a regional focus, mostly preparing or supporting offensive action on the ground. It seems they did also motivate Assad to scrape together some kind of smallish mobile reserves, which can then be supported in action by air power. Assad doesn't appear to have been capable of mobilizing enough reserves, but Russian ground forces or increased economic strength through Russian subsidies may change this. The Russians may be incapable of super-technicised, sophisticated synchronised strike packages including SEAD, aerial refuelling, standoff jamming and whatnot, but at least they appear to have a modicum of art of war understanding. They may soon disappoint in this regard, of course - and I wouldn't mind it with Eastern European security in mind.

Meanwhile, the usual warmonger suspects who write in English have no more sophisticated proposals than to throw more resources at the problem, preferably many ground troops.

Not only those who start a war are responsible for its horrors, but also those who fail to end it quickly.

edit: The Washington Post offers a map of the air attacks, and a description of the recent fighting.

edit2: I noticed that this blog post may be misunderstood. I do NOT mean to assert that Daesh is superior and will win. They are doomed because they made too many enemies, period. It's going to be defeated by land power, though - air power is merely a supportive component.


*: The Turkish government is embarrassing and insulting its own military when it claims they need help from allies, but they don't care because the secular military is not the AKP's darling
**: The Assad regime, which began to rely ever more on Shia and Alawite militias the more the regular army broke apart.



"A pursuit is an offensive operation designed to catch or cut off a hostile force attempting to escape, with the aim of destroying it (...). Pursuit operations begin when an enemy force attempts to conduct retrograde operations. At that point, it becomes most vulnerable to the loss of internal cohesion and complete destruction. A pursuit aggressively executed leaves the enemy trapped, unprepared, and unable to defend, faced with the options of surrendering or complete destruction."

FM 3-90 (U.S. Army), chapter 7

A pursuit usually happens when the opposing forces try to avoid or minimise combat by withdrawal or evasion while friendly forces seek to force a fight on them. Typically, this would be caused by opposing forces feeling unfit for the fight, while friendly forces feel much fitter. It may also be initiated in error, though; the opposing forces may feign weakness and withdrawal, and the pursuing force may run into a trap. The cavalry-centric steppe nomads (Scythians, Huns, Mongols) were famed for such feigned retreats for a thousand, maybe two thousand years.

The typically recommended manoeuvre for a pursuit is not to chase the opposing forces directly (by following the in their trail), but to try to race past them and flank or stop them afterwards. This and pursuit in general puts a very high demand on high speed of movement, while the same applies to those elements of the withdrawing opposing forces that try to provide security for the bulk of opposing forces. Traditionally, (light) cavalry was the branch of choice for pursuit of a beaten army at the tactical level, but at the operational or campaign level entire (mixed) army corps pursue their peers. In theory air and artillery strikes could be used to slow down the withdrawing force, even by scattering anti-vehicle mines. Yet in practice the artillery will likely lack the range and air forces would first need to be convinced to be helpers of the ground forces, enablers of ground forces manoeuvre success, rather than ground forces' rescuers and prime time killers in their own right. To crater a road at a bottleneck would typically mean to not directly drop that bomb on some hostile vehicle for an air force-attributed attrition effect.
"Lediglich frontales Nachstoßen der im fortschreitenden Angriff befindlichen Teile vorderer Linie genügt allein nicht. Der Erfolg wird erst dann erreicht, wenn es gelingt den weichenden Feind
- zu überholen
- zu überflügeln
- sich ihm vorzulegen"
 "Handbuch der Taktik, Eike Middeldorf et al, 1957

(A merely frontal push of the attacking elements of the forward line alone does not suffice. Success will only be achieved if one succeeds to 
- to overtake
- to outflank
- to place oneself in front of 
the evading enemy.)
"It is difficult to intercept and destroy the enemy by merely following the enemy withdrawing from his front and carrying out a pursuit, and it is necessary to push in from the enemy's flank and carry out a pursuit toward the enemy's rear. In other words, it is necessary to be positioned so that the pursuit is carried out from abroad front. In view of the above, in order to intercept and destroy the enemy, pursuit must be carried out over a wide and deep area."
"Principles of War", 1969, p.99

A wide/broad pursuit also reduces the susceptibility of the pursuing force to the feigned retreat tactic somewhat.

Moreover, it's essential to be ready for pursuit (and exploitation in general) at the time of the opportunity. This requires suitable reserves in the right place.

The withdrawing forces are usually not very orderly, not well-secured, demoralised - they are not ready for combat. This offers the prospect of great successes even to small pursuit parties if only those are in a much better state. This is why reserves are so important; those forces that convinced (by combat) the opposing force to withdraw will be morally and physically unfit and would take too much time to regain the necessary order. At least nowadays we could also expect them to be too obsessed about caring for the wounded and some prisoners of war may be burdening them as well.

- - - - -

There is a trivial answer to the challenge of pursuit: Readiness, timing, placing, reserves etc. are all solved problems if only you have a small yet combat-capable force in the back of the opposing forces. Yes, I'm coming back to THIS again. A company-sized element of armoured recce is a sword of Damocles to every opposing forces' manoeuvre commander. It forces 360° security on him, it disrupts his flow of supplies, cuts him off from rotary army aviation support ... and in the event that his brigade runs into trouble and is forced to withdraw said tiny armoured recce element would be ideally placed and highly dangerous for a pursuit action. It wouldn't even need to manoeuvre into position any more. In fact, it would have the choice between maximising attrition by itself and trying to slow down the withdrawing force for a greater pursuit success by larger (and then relatively faster) friendly forces. On top of that, it may cause a panic storm (or accept a disproportionate quantity of prisoners of war surrenders) because the beaten, withdrawing troops would be disheartened by its presence. They couldn't know what caused the noises, the rising smoke columns - and it's quite a stretch to expect forces to withdraw towards or through a threat.

On the other hand, I don't really think that pursuit or withdrawals as described in field manuals should be found in future European-style land warfare. Aside from the fact that there should be peace, evasive manoeuvres and aggressive manoeuvres should be largely indistinguishable until an army formation was really shattered by a well-prepared blow. I suppose that the forces would withdraw in utter disorder (more positive choice of words: "in dispersion"), which is the quickest method of movement and the one that could be stopped the least. This assumes that no obstacle such as a river provides bottlenecks through which only organised forces could pass safely (through engineer efforts or by fighting through an occupied bridge). A somewhat orderly withdrawal of large forces smells very much of the foot-mobile armies of the past. Fully motorised forces would flee very differently.

Coming back to the 'reserves are important' thing: A battalion battlegroup or brigade appears to be the army formation of choice for conventional land war, and usually it would split its combat vehicles into no more than two elements (afaik). There's very little reason to believe that the commanding officer of such a manoeuvre element would keep reserves for pursuit - any reserves would likely be employed to achieve the effect that convinces the opposing force to withdraw in the first place.
"Reserves" don't need to be organic, though. Another battlegroup nearby (less than 50 km away) could be tasked with the pursuit by a higher CO (division or corps level). What matters is that suitable forces are available for the job. It's old-style division-centric thinking to expect these reserves to be held ready by the same CO who led the effort to compel the opposing force to withdraw.
So once again, having multiple manoeuvre elements puts an advancing opposing force at great risk: Two elements could defeat it and force it into a withdrawal with a coordinated two-axis assault, while a third could mount a devastating pursuit. This prospect should serve as a great deterrent, since advancing with one or few manoeuvre elements would put them at great risk. This is somewhat reminiscent of the function of a front line: It would take a concentration of forces (that's not easily overburdened by 360° security and not easily thrown into disorder and ruined by a pursuit) to advance. A couple of manoeuvre elements could be threatening enough to deter an advance by opposing forces this way, without actually getting into contact.
You'd need powerful manoeuvre elements for the assault, but weaker/smaller ones could do the pursuit.



Delaying actions

"A delay is a form of retrograde (...) in which a force under pressure trades space for time by slowing down the enemy’s momentum and inflicting maximum damage on the enemy without, in principle, becoming decisively engaged (...). The delay is one of the most demanding of all ground combat operations. A delay wears down the enemy so that friendly forces can regain the initiative through offensive action, buy time to establish an effective defense, or determine enemy intentions as part of a security operation. Normally in a delay, inflicting casualties on the enemy is secondary to gaining time. For example, a flank security force conducts a delay operation to provide time for the protected  force to establish a viable defense along its threatened flank. Except when directed to prevent enemy penetration of a phase line (...) for a specific duration, a force conducting a delay normally does not become decisively engaged."
FM 3-90 (chapter 11-5)

I'll spare everyone the nitpicking about that definition. My short(er) definition is as follows:

"A delaying action serves the purpose to slow down the advance of opposing ground forces by yielding ground for time. It is preferable for the defending force to not get fixed or engaged decisively. Slowing down the opposing forces typically is prioritised over reducing them."
I personally consider delaying actions as the dominant part of modern mobile warfare. Forces would be thinly distributed in most areas of a theatre of war due to a low ratio between forces and area, so "economy of force" is most important in most places. Save for harassment a delaying action can be executed with the worst ratio of friendly to opposing forces if only the friendly forces are technically no less mobile than the attacking opposing forces. This typically poor ratio of forces is what makes a delaying action "demanding" according to the U.S.Army definition above.
Befitting von Clausewitz' Schwerpunkt concept, you need to minimise defences in most places in order to amass enough or as many as possible forces for the Schwerpunkt or the main effort for decisive offensive action. Those reserves freed from failing in 'defending everywhere' could also have a "fleet in being" effect of deterring major hostile offensive operations by being available for counterstrokes.

Now about the textbook version of delaying actions (aggregated from many sources, not only the FM 3-90):
You divide the share of friendly forces that are suitable (speed, morale, training, equipment, supply state) into at least two different elements.
Engineers reduce the trafficability of the routes (blowing up bridges, cratering roads at bottlenecks, flooding terrain, causing forest fires to make forest roads impassable, fake and real mines, removal or manipulation of road signs etc.).
The element more close to the advancing opposing forces tries to force them off the road with long-range artillery fires (to slow their movement), and then forces them to deploy into battle formation (slower than march column) with a far ambush. A prioritisation of slowing down instead of attrition would typically suggest that this friendly force makes its presence known before the far ambush in order to force the opposing force to deploy and thus spend time without substantial line of sight combat (Remember? No decisive engagement!). A greater emphasis on attrition and an effort to build up a reputation for dangerous far ambushes early on would require to execute the far ambush for real. The problem is then to avoid decisive action even through the opposing force can move at 50+ kph on the battlefield and line of sight are often only 500-3,000 m and can be reduced further by obscuration efforts (mostly artillery-delivered multispectral smoke). 
The defenders risk being overrun by a rapid counter-ambush assault. Obstacles (such as scatterable mines) may help in this regard.
A frontal far ambush makes withdrawal of the ambushers less difficult and an attempted flank attack on it costs the attacker more time, while a flanking far ambush allows for a better attrition effect, particularly the destruction of other than lead elements (such as bridgelaying and minesweeping tanks, which in the end may have a greater slowing effect).

So the defenders force the attackers to deploy, waste time in a minefield or unsuccessful flanking move and ideally withdraw in time to avoid decisive (close) combat, though possibly causing and suffering some attrition.
This forward delaying element then withdraws, and an incompetent delaying action would demand this very same force to set up the next far ambush itself. A competent commander would instead have arrangements for a second element to allow the retreating friendly forces to pass and execute the next far ambush. It's impossible for a single element to maintain a delaying effort without vastly superior mobility.

- - - - -

Now about the modern picture:

(1) The advancing opposing forces are nowadays an all-offroad capable, all-motorised force. This is true even of Toyota technical-based improvised civil war forces in developing countries.
They can move in dispersion, with individual platoons or companies moving with several kilometres spacing. The delaying effort could then be the sum of (small) unit engagements. Attrition would naturally become more prevalent (since every far ambush salvo might eradicate an entire manoeuvre element) and frontal assaults (overrun attempts) on far ambush positions less likely. Flanking on the other hand would be more easily against the defenders, since inevitably some advancing manoeuvre elements will be farther forward than others.

(2) There's likely no front-line going to be established soon for want of enough forces, thus it's not so risky to be "behind" opposing forces any more. No front-line will cut such forces off any time soon, after all.
This allows for an alternative and supplement to the far ambush, especially on the operational (~corps command) level of war: Substantial forces* "left behind" or manoeuvring into positions behind an advancing hostile force would threaten its supply lines and its support elements (which are only marginally capable of line of sight combat). This would at the very least force a 360° security effort on the advancing opposing force, turning it into a moving pocket. This means a weakened tip of the spear and thus less offensive power (making delay by far ambush easier and attrition more important), but it's also most uncomfortable for the opposing commander. He might be tempted to 'clean up' those elements in his rear, which of course would cost a lot of time, since those elements can resist removal by a delaying effort of their own. A delaying effort in the 21st century does thus not need to be about withdrawal (the attacking opposing force may well move away  from the bulk of friendly (our) forces when engaging a pesky element in its rear). Accordingly, it also doesn't need to be about trading space for time. In fact, space may be gained if the opposing force attempts to get rid of an element in its rear.

(3) Delaying actions may be considered to be shaping operations.
To slow an opposing force down allows for less-impeded friendly elements to manoeuvre into position for a decisive engagement (for a synchronised pincer attack, for example). To force a 360° security effort on the opposing force may reduce the surprise effect on such an action, but also reduce the opposing force's ability to resist it. A delaying action may also be used to slow down a withdrawal (another reason why a delaying action isn't necessarily trading away territory) in order to make a pursuit more effective.
Delaying actions may also be kept the dominant choice of course for days in order to build up forces or to exploit superior long-range artillery firepower or superior air/ground attack strength. Entire army corps might refuse to offer battle brigades vs. brigades if this improves their odds of success.** Tactics treaties are often excessively focused on how to win a battle during the battle, while the preferable course of action is to refuse battle until shaping operations almost guaranteed success in battle. This necessitates some alternative effect (other than battle or front-lines) to keep the opposing forces from advancing and accomplishing their objectives in the meantime.

(4) Delaying actions should refuse decisive actions, that is the delaying elements should avoid their own destruction. That's generally a good idea, but as mentioned before, the ratio of forces is usually disadvantageous in a delay, so offering battle to the death (of either the friendly or the hostile element) is typically a losing proposition in a delaying action. The problem nowadays is that about 80-90% of casualties are caused by indirect fires (non-line of sight combat) in conventional warfare, so the classic view that the delaying element would risk its destruction primarily in close line-of-sight combat is probably inaccurate and obsolete. Sure, close combat may still eliminate the element and make its withdrawal very, very difficult. Yet its destruction (or attrition high enough to make the element incapable of staying on its mission) is more likely by repeated artillery (and other support) fires. The focus for survivability on a delaying action mission should thus not be on avoiding close combat any more. Instead, it's important to avoid artillery and other support fires. Short range air defences, withdrawal within 2-3 minutes after giving away one's position, irregular movements to avoid shelling on the move between ambush positions and so on will require additional capabilities and efforts and narrow down the freedom of action of the delaying forces.
On the other hand, the destructive and inhibiting effects of indirect fires may be used to greater effect than ever before in the delaying effort itself. Modern artillery typically has about 30 km range, about 40 km with fewer munitions and 80-100 km range with very few munitions. A moving opposing force could be threatened by artillery almost at all times, potentially forcing it into a dispersed and offroad movement instead of a quick and efficient road march even without classic delaying actions (far ambushes).

- - - - -

I insist that delaying actions are very, very important in modern conventional (state vs. state) mobile warfare. Meanwhile, field manuals still appear to imply that it's a poor man's choice and to be avoided if possible. Instead, I would consider it as the first choice, in preparation for (possibly never happening) brigade-on-brigade battles later on.


*: More than long-range scouts / LRRP / Fernspäher and in this case no Jagdkommando, for I emphasise mobile warfare and thus mounted combat in this text. I'm rather thinking of quite combat-capable armoured recce units.
**: I really need to write about the 'fleet in being' effect sometime.


Political resolve for collective defence

There are occasional polls about alliance resolve, and whether the populations of certain countries would be willing to go to war if the alliance was attacked. A recent one incidentally asked this again, with a somewhat typical result.

I strongly doubt that such hypothetical poll questions are useful at all.
Aside from that, translations often change the actual meaning and most likely interpretation of a question very much, so you need to know the actual question and know the language to actually understand what was asked. I inquired the pollsters from earlier such polls for the German wording of the question, and none ever replied - so I won't give them the benefit of a link.

'Some people' simply LOVE  such poll results, for they fit to their prejudices, and then many of them go on fantasizing further. I won't honour this with any links either.

Instead, let's look at how the political mobilization for war actually looks like historically and likely also in the future.
In modern times an important step was to kill the idea that war is avoidable. An aggression by another power makes this obvious (reducing the question to whether to participate). Aggressors need to use different devices; typically a great urgency is suggested (such as Blair's lie about "45 minutes" threat by Saddam's non-existing missiles), or poor defenceless people about to be massacred (Kosovo, Russian intervention in Eastern Ukraine, and the story about Yezidis on a hill encircled by ISIS eerily sounded like a failed try, though it was partially true).

Another important step is the endorsement of war. Trusted figures - politicians*, journalists* - support going to war or abstain but favour it (by the choice of topics, guests and narratives for political discussions, for example). This would happen before almost any war, but is absent in advance of any poll about political resolve to defend the alliance.

And then there's the general manufacturing of consent**, a kind of crowd-sourced subconscious propaganda effort by political parties and the press that favours a certain narrative to the degree of eliminating dissenting ones from almost all public discussions.
I must admit that Putin somewhat undermined the manufactured consent of the West by somehow attracting at least many far right folks as a kind of hero of theirs, establishing a channel for a Russia-favouring dissenting narrative. Sadly, they've so far never been more fair than the establishment one and the establishment narrative would almost certainly prevail in the foreseeable future.

Last but not least, we don't have plebiscites for the decision to go to war. Almost any German government would agree*** to article 5 proclamation and initiate V-Fall / Verteidigungsfall (state of war) without hesitation if the alliance defence criteria were objectively met by an aggression. There may be some salami tactics-style minor border incident that would not trigger such a maximum response, but most likely it would lead to a Spannungsfall (military mobilisation).
There's no realistic option for a German government to limit participation in collective defence to token, symbolic contributions even if it wanted to: Many German military forces are under NATO command and would not be directed to deploy by the German minister of defence or chancellor, but by the CO of SHAPE once there's an aggression.

And yes, we'd ignore much red tape if there's an actual war. We'd have to.

Thus in short: Nobody is 'ever going to gain my respect' for his or her 'quality of thought' by proclaiming that Germans would not defend NATO.****

_ _ _ _ _

And now a special message to Americans: It's disrespectful to question German resolve to defend the alliance in the event of an actual aggression against it. After all, we agreed to the article 5 activation and participated in that Afghanistan bollocks of yours because of it - in response to anything but an actual aggression against the alliance. The Baltic countries and Poland may discuss this topic, but you Americans better join the waiting queue on this topic at the very end!


*: Probably "trusted" less than ever before, so maybe this isn't all that applicable to near-future conflicts any more). 
**: I introduced this term 'manufactured consent' only recently on this blog, but I've actually read the book more than a decade ago already. I added this line of argument to the blogging because revisiting the old meta topics became somewhat stale. 
***: Anything else is unthinkable in the German political landscape that saw even the greens agree to the Kosovo war. We can revisit this diagnosis once there's a PDS Die Linke-only administration (that's never going to happen unless the Soviet Union reappears and overran us).
****: It's different with EU members that are no NATO members; hardly anyone perceives the EU as an alliance even though it's one. The media would probably hurry up to put the spotlight on this in the event of an aggression.


Breakpoints in land battles

A comment by kesler12 asked me to provide some support for my claim that in actual battle units usually break after losing a minority of their strength (the context was that simulated combat where men do not fear for their lives tends to have much higher casualty rates and much more resolute defences).

I couldn't find the original summarising article or report that I would have preferred to supply and I sure won't even try to assemble the dozens if not hundreds of separate tiny bits that form the general picture, but I did find an old study with a statistic analysis that seems relevant:

Robert L. Helmbold, RAND Corporation, 1971

He tried in typical (then still new) operational research style to develop a formula for calculating when a force would 'break' and retreat. His hypotheses had to be tested, and he used a database of 1080 historical battles, and the author produced these diagrams:

As you can see, the winning defenders suffered up to 20% casualties in about 90% of the battles and 20-25% casualties in another about 5% of the battles. Meanwhile, the attacks - which faltered obviously - suffered less than 40% casualties in more than 90% of the battles.

Next, the same from 612 battles won by the attackers. Again, about 90% of the losing defenders suffered "only" up to about 40% casualties.Keep in mind that it's a rule of thumb that usually more casualties occur during pursuit than before the defence broke!

These were historical battles, many of which were rather unlike modern combat engagements, but human nature largely stays the same, I suppose. Either way, the results are so very striking in support of the assumption that defending forces yield after suffering less than 50% casualties that this should be accepted as true IMO.

What I remember from the old summarising article that I keep not finding (I suspect it's in Infantry Magazine 1990's, Armor magazine 1980's or 1990's or in Military Review somewhere, or maybe it's some RAND report.) is:
Many defences break after 10-20% casualties over a time span of hours or days. The most resolute "stubborn" defending forces suffered up to 40% casualties before retiring.
Other sources support more assumptions:
Only encircled forces or forces that couldn't flee (such as Japanese island defenders) went to 80% casualties and beyond without routing. Attacks stall after similar (lower) casualty rates as defences break, and they stall the earlier the more "veteran" and less "youthful" the units are. "Veteran" units tend to be more stubborn (less fragile) defenders (and less vigorous attackers), and so are forces with a higher share of married men (who tend to be less prone to give up).