The problem with Lethality

Why increasing lethality is the wrong approach to winning wars

Photo Credit: U.S. Marine Corps photo by Staff Sgt. Donald Holbert

Lethality is the new buzzword, but is that really what armed forces (only) ought to pursue? I have my doubts, let me explain why.

First, what is meant with the term lethality? The US army definition is the following: “Lethality is the capability to effectively neutralize or destroy the enemy target, a critical component of combat effectiveness.”(FM 3-0 Operations)[1] The US and UK Armed forces are seeking to become more lethal.[2] The US army even goes as far as weeding out everything that does not contribute to lethality.[3] The UK Army on the other hand aspires to achieve a ten-fold increase in lethality.[4] The word ‘lethality’ alone appears at least 144 times in the UK Strategic Defence Review.[5]

Lethality ≠ Winning
Let’s do a simple thought experiment. Let us imagine that the only thing you could achieve was killing your enemy (ie. being lethal), this would be your only intent. What if you are confronted with an enemy that will not give up and is willing to die for his or her country, up until the last fighting age male of female? What if you do not pursue any other strategy than neutralize or destroy all of these enemies? Again, it’s all about lethality, deterrence is merely a side-effect when pursuing this strategy. As long as the enemy is not willing to surrender, you would need to kill all the fighting age male and women in order to win. That would not only be a very costly strategy, but it would also leave you with little left to rebuild the country after the war. The result of such a strategy is attrition, of what we see happening now in Ukraine, or what has happened in World War I.

“Through most of its wars, the United States successfully used the attrition approach. It is easier to be proficient at this type of warfare. You need to master only the simplest military skills and possess enormous quantities of arms and munitions.” – Jim Dunnigan

Do adversaries like these exist? We have already encountered several of these types of adversaries in the middle-east. The current war in Ukraine also shows the perseverance of the Ukrainian population. The same is in a sense true for the Russians. The tolerance of the Russian leadership towards the immense number of losses and the disregard for the lives of their soldiers is insane. Will killing more Russian soldiers really bring victory? If there is one country in the world that has a track record of not giving a f* about losing soldiers, then Russia is likely somewhere at the top. China will probably also rank high on this list. However, both Russia and China happen to be the most likely adversaries of the West in any future conflict. If so, is pursuing lethality then really our best strategy?

Winning wars is not always about who kills or destroys the most, but about forcing your enemy to surrender. When you break the will to fight, you don’t necessarily need to be lethal. Was there ever a war where lethality was the key to victory? Of course, killing your adversaries is and will likely always remain a necessary part of war, but it is about forcing or influencing those that are still standing, or havent picked up their weapons yet.

There are several arguments for why lethality is not only a sub-optimal strategy to pursue, but one that has become detrimental. I am also not the first to write about this.[6] One reason why lethality is a bad strategy to pursue is that it blinds us to other options. Or as Jeremy D. Lawhorn explains in Small Wars Journal: “… solutions should be human-centric, focused on how to change behaviour within the current environment without automatically assuming that increasing lethality will generate the desired results. Placing lethality at the centre of the security calculus represents a skewed approach to effectively aligning ends, ways, and means.”[7] Lethality can also blind in an ethical sense, for there is an increased risk of dehumanizing the adversary and possibly even civilians.[8]

If there is one thing that we need to learn from the current war in Ukraine, it is the possibility that we too fall into the trap of attritional warfare, and this is what we ought to avoid, at all costs. Manoeuvre warfare and mission command are solutions that were invented to counter this problem. This hardly sounds innovative, but sometimes we already have learned valuable lessons. We simply seem to forget them somehow.

History again
Yes, I am going to refer to the German invasion of Western Europe, again. Of course these battles have been discussed all too often. However, I am convinced that there are still important lessons to be learned. After world war I, the Germans focused on one thing: how to avoid the war of attrition of 1914-1918. The Allies however, perhaps ignorant about their victory in this war, did not feel the same urgency to learn and adapt. Perhaps this also has to do with their defensive posture, whereas the Germans were planning for the offensive. One might argue that NATO is in the same position, preparing for the defending Europe (or the pacific).

My earlier post (Strange Defeat) on how the French experienced the German invasion of 1940 shows how an attritional approach can be destructive, and how a manoeuvrist approach can break the will to fight. The following passages by Marc Bloch are illustrative: “I saw men who had the day before gone into the line under murderous fire without turning a hair, run like rabbits…..” Because, Bloch explains: “The Germans turned up where we didn’t expect them and where we had never been told we ought to expect them.” [9]

Time – Space – Force
Manoeuvre is a means, not an end. What needs to be achieved is surprise and unpredictability. Trying to fight an enemy you don’t understand and that is continuously one step ahead is what makes you lose morale. This means varying in time, space and force.
Time: attack when they do not expect you to be ready or there yet. Marc Bloch explains that this one time, an officer encountered a column of tanks driving in the wrong direction. The officer ran towards the column in order to tell them of their mistake but was stopped in his tracks by a local farmer, who explained that these were German tanks, not French.[10] (which were driving in the correct direction, from a German perspective).
Space: be there were they do not expect you to be. The push through the Ardennes was not expected. Even when the original plans were intercepted by accident, they were ignored because they were deemed unlikely. The Germans even pulled of this trick a second time in 1944, successfully.[11] The Ukrainian offensive in Kursk (2024) is also a good example of using space wisely.
Force: besides timing and location, the quantity, quality or formation of your troops (ie. the force) can provide unpredictability. New weapon systems are also a prime example for achieving surprise. The effect however is always limited because the adversary will likely adapt and find ways how to counter these weapons eventually. The fiber-optic (wired) drones being used by both the Ukrainians and Russians nowadays is a good example of a new weapon system that likely achieved some surprise at the beginning.[12] Yet in a war of attrition these tactical and technological successes are limited. When you don’t exploit unpredictability and just focus on lethality, your advantage will likely be temporary for you will give the enemy time to adapt. Of course, advocates of lethality can argue that your enemy can’t adapt when there dead, but this overlooks the likelihood that you won’t be able to kill all your enemies. Besides the atomic bomb, few weapons have had this effect on adversaries. Moreover, the enemy might as well copy your technology and use it against you, like with the fiber-optic drones.

My hypothesis is therefore: you need to become unpredictable to your adversaries, while simultaneously being able to predict what your adversary will do.
We use to say in the Army: “hope is a bad military principle, no plan should rely on hope”. However, humans need hope to continue fighting. Hope is something that is hard to grasp, but we all have a sense of what this means. When you feel defeat is unavoidable, and moreover, when you are unable to grasp what you are up against, then most people will eventually give up. You don’t necessarily need to kill your enemy, when they are forced to lay down their weapons, or even better, not even willing to pick them up in the first place.*

Thank you for reading! As of now, there will only be free-subscriptions to Beyond the Art of War. If you do want to make a contribution, you’re welcome to buy me a coffee!

The views expressed are those of the author and do not reflect the official position of the Armed Forces.

Note*: Some might say that this is cognitive warfare, but I would disagree. You still need to become unpredictable by using time, space and force to your advantage. Influencing what and how people think without manipulating the physical dimensions is likely very limited. Let me know in the comments if this is something you like me to elaborate on in a future post.

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[1] https://www.forscom.army.mil/Lethality/

[2] https://api.army.mil/e2/c/downloads/2025/05/01/c4c9539c/letter-to-the-force-army-transformation-initiative.pdf

[3] https://www.defense.gov/News/News-Stories/Article/Article/4220986/army-plans-to-eliminate-programs-not-contributing-to-lethality/

[4] https://www.gov.uk/government/publications/the-strategic-defence-review-2025-making-britain-safer-secure-at-home-strong-abroad P 20

[5] https://www.gov.uk/government/publications/the-strategic-defence-review-2025-making-britain-safer-secure-at-home-strong-abroad

[6] The Perils of Lethality • Stimson Center

[7] Pursuing a Strategy for Yesterday’s War | Small Wars Journal

[8] The epistemology of lethality: Bullets, knowledge trajectories, kinetic effects | European Journal of International Security | Cambridge Core

[9] Marc Bloch, Strange Defeat, P49

[10] Marc Bloch, Strange Defeat

[11] https://en.wikipedia.org/wiki/Battle_of_the_Bulge

[12] https://www.bbc.com/news/articles/ckgn47e5qyno

Image source: THERE'S MORE TO LIFE THAN LETHALITY - War Room - U.S. Army War College

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Bibliography:

Marc Bloch, Strange Defeat (2019: Must Have Books, Victoria)