Clausewitz’s Friction Revisited 

January 2025

Introduction[1]

In the winter of 1862, General Burnside of the Union army planned to cross the Rappahannock River and trap General Lee and his Confederate troops in a pocket. When Burnside ordered his army in motion, heavy rain began, turning the roads into mud.[2] Eager to bring about victory and optimistic that the weather and roads ahead would improve, the general decided to march on.[3] The next day, however, the troops were bogged down without having crossed the river, and most equipment was immobilised.[4] Ultimately, Burnside had to order his men to retreat while Confederates taunted them from across the river bank.[5]

General Burnside’s “Mud March” is one of many examples of the great impediments to efficient military action created by what Carl von Clausewitz called “friction” – the unified effects of chance, uncertainty, and human shortcomings that make war in real life very different from war on paper: an ultimately unpredictable endeavour.[6] The concept of friction is one of Clausewitz’s most referenced ideas and has been widely applied from battles[7] to operations,[8] wars,[9] logistics,[10] command,[11] and missile defence,[12] as well as in other fields such as environmental history[13] or business.[14]

In recent decades, however, the advent of military technologies such as satellite navigation, signals intelligence, unmanned sensors, precision-guided weapons, and digital communication – the most recent so-called revolution in military affairs – has led to claims that these new technical means of war enable complete knowledge of the battlefield and perfect control of weapon effects, supposedly “lifting the fog of war”[15] and making the concept of friction obsolete.[16] Such claims raise the question of whether friction is an enduring feature of war, that is, part of its nature, or if technological progress could overcome its adverse effects on war and warfare.[17]

This essay contests these contemporary voices and argues that as long as war is a human undertaking, chance, uncertainty, and human error will prevail, making Clausewitz’s concept of friction a structural element of war that can be reduced but not eliminated. To that end, Clausewitz’s unified concept of a general friction is presented. Then, a more detailed assessment of the role and persistence of chance, uncertainty, and human shortcomings in war is conducted. I seek to explain friction by what Clausewitz wrote rather than by what others have said about him. Thus, I focus on Clausewitz’s writings and use secondary sources mostly to contrast different interpretations.

The Unified Concept of a General Friction

In On War, seemingly contradictory, Clausewitz wrote that “everything in war is very simple, but the simplest thing is difficult. These difficulties accumulate and create a friction that no one who has not seen war can really imagine.”[18] He further observes that in war, “everything seems so simple, all necessary knowledge seems so trivial, all combinations so insignificant,”[19] but also emphasises that “everything is very simple, but not therefore also very easy.”[20] So, what does Clausewitz mean by simple? Why are the simple things difficult? And what is friction really, what does it lead to, and what can be done about it?

When Clausewitz speaks of all things in war being very simple, he refers to war and its activities in theory, arguing that constant repetition in thought and exercise makes them routine operations for officers and soldiers that can be planned and exercised without many difficulties:[21]

“Marches for a circumvention on the right or left are easily devised; the idea of keeping a small formation always concentrated to be a match for the enemy at any point, to multiply forces by rapid movements, is as easily conceived as expressed; (…) and of such simple things nothing remains than to admit that they are simple.”[22] 

According to Clausewitz, difficulties only arise when a plan is executed, and commanders are obliged “to deviate from it a thousand times by a thousand influences.”[23] He calls these influences friction, an “invisible factor that is effective everywhere,”[24] which “makes the seemingly simple difficult”[25] and “distinguishes real war from war on paper.”[26] Here, Clausewitz expresses the core of friction in war as it actually is (der eigentliche Krieg): the exposure of even the best plans, intentions, and theories to chance, uncertainty, and human failings can have immense effects on the outcome of battle and war. Helmuth von Moltke later reflected this notion in his famous dictum that “no operational plan extends with any certainty beyond the first encounter with the enemy’s main force.”[27]

All the sources and elements that make up friction are summarised under Clausewitz’s unitary concept of a general friction (Gesamtbegriff einer allgemeinen Friktion), encompassing “the danger, the physical exertion, the uncertainty, and chance,”[28] which will be discussed in more detail in the next section. According to Clausewitz, through their chaotic effects on decisions, morale, and actions, these factors can impede the realisation of set objectives to varying degrees, possibly even leading to defeat.[29] This reflects Clausewitz’s critique of military thought during the early 19th century, which proposed ways of creating mathematical approaches to war, “rational principles based on hard, quantifiable data that might reduce the conduct of war to a branch of the natural sciences.”[30] Clausewitz believed such drawing board exercises to be overconfident and contradicting war as it actually is, which he believes can only be known – but never predicted – through experience, not “from books or the drill-ground.”[31]

While Clausewitz emphasises the immense significance of friction in war, he does not despair about it. First, he argues that through experiencing war, “everything becomes apparent”[32] and one comes to know friction, which can be incorporated in planning and reacted to in battle.[33] Second, Clausewitz considers military genius, comprised of determination, strength of character, boldness, courage, and self-reliance, to be able to overcome the effects of friction.[34] Third, he articulates various means and measures to reduce friction and its effects on military action, such as flexibility in battle,[35] exercises close to battle conditions,[36] or learning lessons from other wars during peacetime.[37]

In summary, Clausewitz’s concept of friction describes the difference between planning and making war, where even well-trained, “simple” actions may go awry because of the unpredictable effects of chance, uncertainty, and human failure. Nonetheless, Clausewitz is convinced that the effects of friction can be reduced through wartime experience, strong leadership, and peacetime preparation.

Friction in Action

In this section, the individual elements of the unified concept of a general friction – chance, uncertainty, and human shortcomings[38] – are presented in more detail and illustrated through a selection of brief examples. To demonstrate the persistence and omnipresence of friction, cases are chosen from the 18th century to today and from the strategic, operational, and tactical levels of war.

Chance

In his famous trinity, Clausewitz describes war as comprising the tendencies of the people (animosity and hatred), of politics (reason), and of the general and his army: probability and chance.[39] For him, “there is no human activity that is so constantly and so universally in contact with chance as war.”[40] This “play of possibilities, probabilities, luck, and misfortune”[41] makes war a gambling game for Clausewitz, in which calculations of probability dictate action and unforeseeable events can determine the winner.[42] In war, chance events such as changing environmental conditions,[43] the failure of equipment,[44] or simple accidents produce, by definition, “phenomena that cannot be predicted”[45] but can heavily affect the execution of plans, leading to outcomes falling short of the mark:[46] 

“Here the fog prevents the enemy from being discovered at the right time, a gun from firing at the right time, a report from finding the commanding officer; there the rain prevents a battalion from arriving, another from arriving at the right time because it had to march for perhaps eight hours instead of three, [and] the cavalry from being able to hit the ground effectively because it gets stuck in mud.”[47]

For Clausewitz, the pervasiveness of chance in war makes it a chaotic endeavour, “inherently unpredictable by analytical means,”[48] which contemporary authors have compared to chaos theory and non-linear science.[49] But chance works both ways, and as Waldman observes, “is essentially neutral: it can create possibilities and opportunities to be exploited, or equally dash the best laid plans.”[50]

The role of chance in war is well illustrated by the so-called “Second Miracle of the House of Brandenburg.” In 1762, six years into the Seven Years’ War, Prussia’s situation in its war against the coalition of Austria, France, Sweden, and Russia, among others, was dire, and “defeat appeared imminent.”[51] Prussian force strength and quality were declining, morale was low, and the enemy coalition prepared the final blow against Frederick the Great. Then, surprisingly, the Russian empress Elizabeth died, and her nephew Peter succeeded her on the throne. German-born Peter idolised Frederick and even had his personal guard wear Prussian uniforms.[52] He immediately made peace with Prussia and supplied 20,000 troops to Frederick’s war effort.[53] While Peter was dethroned soon after, his actions allowed Frederick to concentrate forces against Austria, decisively defeating them in the Battle of Burkersdorf, after which the Austrian empress made peace and relinquished the reconquest of Silesia.[54] The sudden death of Elizabeth at this time thus constitutes an act of friction with immense effects on the strategic level, beneficial for Prussia and detrimental for the coalition. Arguably, if Russia had not made peace, Prussia would have been reduced to a minor power, and Austrian power in Europe vis-à-vis other German-speaking states would have been consolidated.[55]

Uncertainty

For Clausewitz, “war is the domain of uncertainty; three-fourths of the things on which action in war is built lie in the fog of a greater or lesser degree of uncertainty.”[56] In the context of friction, uncertainty refers to the ever-present lack of perfect information in the planning and execution of military action, a “want of insight,”[57] which requires commanders to make innumerable assumptions, each of which can ultimately be a fatal misjudgment.[58] According to Clausewitz, “the difficulty of seeing things correctly (…) is [therefore] one of the greatest frictions in war.”[59]

Uncertainty is pervasive and covers, among others, the capabilities of one’s own forces, the strength of the enemy, and the enemy’s intentions and morale.[60] This gap between necessary and actual knowledge is further exacerbated by deception, counter-intelligence, rumours, human error, and the limits of human cognition.[61] Together, the friction caused by uncertainty can lead to delay, hesitation, untimely action or inaction, and overconfidence – all possibly decisive mistakes.[62]

The 2024 Kursk offensive offers an apt example of how uncertainty prevails even in contemporary wars, where ubiquitous intelligence, surveillance, and reconnaissance (ISR) assets have supposedly made battlefields “transparent” by enabling the tracking of “any troop movements by either side, making it all but impossible to hide massing forces and concentrations of armoured vehicles from the enemy.”[63] When the Ukrainian armed forces launched their incursion into Kursk Oblast in early August, Russian border guards and military units were caught by surprise and initially offered little to no resistance.[64] After a week, Ukraine had captured 1,000 km2 of Russian territory, making further gains until late September.[65] Only from October onwards was Russia able to concentrate sufficient forces to push back the incursion.[66] The Kursk offensive shows that even with its highly advanced ISR capabilities, Russia was unaware of the Ukrainian intention to strike into Kursk and either did not register the massing of forces close to the border or did not consider it a serious threat. Moreover, even after it started, Russia was not capable of grinding down the advance with long-range strikes and attack drones due to Ukrainian columns being protected by electronic warfare and air defence assets, severely impeding ISR and target acquisition.[67] The Russian lack of information about Ukraine’s intentions and movements before and during the offensive thus shows how uncertainty in war – friction – prevails on the operational level even when fielding advanced technologies.

Human Shortcomings

War is a human endeavour, and humans, Clausewitz emphasises, are not perfect machines but prone to all kinds of mistakes and shortcomings. War “has to deal with living and moral forces,”[68] which are, other than material factors, difficult to comprehend and impossible to predict.[69]The fear induced by the dangers of war, that is, possible death and mutilation in battle, has severe psychological effects on the morale and performance of soldiers and commanders alike.[70] Similarly, the physical demands of march and battle quickly affect the willingness and capability to perform well in combat.[71] These factors, the psychological and physical impediments inherent to human beings, can undermine discipline, demoralise an army, and lead to mistakes, misunderstandings, wrong decisions, and failure to carry out orders.[72]

Clausewitz stresses that moving a battalion on a map is very easy but that “the battalion remains composed of many people, the most insignificant of whom, if chance would have it, is capable of causing a halt or other irregularity.”[73] The human elements of war, the individual soldiers and the commander, thus each harbour the potential for significant friction, which is exacerbated by the constant interplay of thousands of friction-prone individuals.[74]

The potential grave consequences of human error in war are aptly illustrated by the failed destruction of the Ludendorff Bridge at Remagen in 1945. As one of the few intact Rhine crossings, its timely destruction was a priority for German forces to slow the Allied advance.[75] When Allied troops approached, Major Hans Scheller first decided to hold up the demolition to allow a German artillery unit to reach and cross the bridge.[76] Then, the explosive charge, which was only half the required amount and of weaker industrial rather than military grade, did not detonate at first. When the explosion finally succeeded, it was not powerful enough to destroy the bridge, allowing the Allies to capture it intact and bring six divisions across before it collapsed ten days later.[77] The delay in destruction may be attributed in part to the earlier court martial and execution of officers responsible for a premature bridge destruction, which could have instilled fear in Scheller of suffering the same fate.[78] Nonetheless, his prioritisation of the artillery unit over the demolition was a wrong tactical judgment, which, combined with the engineers’ failure to install sufficient explosives, contributed to the rapid collapse of German defence eastward of the Rhine. The bridge of Remagen thus shows how fear, stress, and incompetence of individuals on the tactical level can have immense consequences for one’s overall war effort.

Conclusion

This essay has presented Clausewitz’s unified concept of a general friction and demonstrated the significance and persistence of chance, uncertainty, and human shortcomings in war throughout history and on all levels of war. The essay has shown that friction is a structural feature of war that can be reduced through experience or technology, but cannot be removed from war as long as humans still play a part in it. Therefore, even 200 years later, both observers and practitioners of war can only be advised to use Clausewitz’s analytical tools, of which friction is only one, to better understand their profession. Peter Paret has aptly summarised this enduring value of friction: “Everyone knows that unexpected changes in weather, misunderstood orders, and accidents may affect events. By grouping such occurrences under the concept of friction, Clausewitz turned them from ideas of haphazard familiarity into a firm component of an analytic description that seeks to explain its subject.”[79]

Notes

1] All translations from German were made by the author.[2] Brady, “Nature,” 127.[3] Ibid.[4] Ibid.[5] Ibid.[6] Stone, Military Strategy, 9–10.[7] Michot, “Labadieville.”[8] Stone, “Military Strategy,” 42–55.[9] Jemirade, “Iraq.”[10] Lere, “Logistics.”[11] Samuels, “Command.”[12] See Cimbala, “Missile Defense.”[13] See Brady, “Nature.”[14] Gilroy, “Business.”[15] Owen, “Fog;” Karlsrud and Rosén, “Lifting.”[16] For an overview of frictions’ alleged obsolescence, see Strachan, “Clausewitz,” 135; Waldman, “Shadows,” 350–351; Watts, “Future War,” 1–6.[17] See also Cimbala, Chaos; Lere, “Logistics,” 10; Waldman, “Shadows,” 350–351; Watts, “Future War,” 3–4.[18] Clausewitz, Vom Kriege, 261.[19] Ibid.[20] Ibid., 347.[21] Ibid., 346–347.[22] Ibid., 349.[23] Ibid., 347.[24] Ibid., 261, emphasis added.[25] Ibid., 264.[26] Ibid., 262.[27] Moltke, “Über Strategie,” 291. [28] Clausewitz, Vom Kriege, 237, 265.[29] Ibid., 261; see also Holmes, “Chaos,” 141; Michot, “Labadieville,” 129; Paret, “Clausewitz,” 203; and Stone, Military Strategy, 10 for different assessments on the degree of negative effects on military action as well as on positive effects from the enemy’s friction.[30] Howard, Clausewitz, 13; Watts, “Future War,” 22–23.[31] Clausewitz, Vom Kriege, 208, 261, 263–264, 350.[32] Ibid., 261, emphasis added.[33] Ibid., 263[34] Ibid., 208, 261–262, 346–347; see also Holmes, “Chaos,” 141; Paret, “Clausewitz,” 202–203; and Waldman, “Shadows,” 356–358 for assessments of the interplay of friction and military genius.[35] Clausewitz, Vom Kriege, 345.[36] Ibid., 266.[37]Ibid. See also Samuels, “Command” and Stone, Military Strategy, 10 for contemporary approaches to reduce friction.[38] Henceforth, danger and physical exertion are considered together as human shortcomings.[39] Clausewitz, Vom Kriege, 213.[40] Ibid., 207.[41] Ibid., 208, 213.[42] Ibid., 207, 208.[43] Brady, “Nature,” 131.[44] Stone, Military Strategy, 10.[45] Clausewitz, Vom Kriege, 262.[46] See also Samuels, “Command,” 40; Waldman, “Shadows,” 344.[47] Clausewitz, Vom Kriege, 262.[48] Beyerchen, “Nonlinearity,” 90.[49] Ibid., 76–77, 90.[50] Waldman, “Shadows,” 360.[51] Byman and Pollack, “Great Men,” 107.[52] Ibid., 107; Seewald, “Preußen.”[53] Ibid.[54] Ibid.[55] See Byman and Pollack, “Great Men,” 107.[56] Clausewitz, Vom Kriege, 233. As Clausewitz does not use the often-quoted term “fog of war” and does not particularly emphasise fog as a metaphor for uncertainty, this essay also refrains from its use.[57] Ibid., 206.[58] Ibid., 206, 348.[59] Ibid., 259, emphasis in original.[60] Stone, Military Strategy, 10; Paret, State, 197–198; Waldman, “Shadows,” 346; Watts, “Future War,” 9–10.[61] Clausewitz, Vom Kriege, 258; Samuels, “Command,” 40; Waldman, “Shadows,” 349; Watts, “Future War,” 84.[62] Waldman, “Shadows,” 352.[63] Gady, “Drones.”[64] Sabbagh and Sauer, “Kursk attack.”[65] The Guardian, “Kursk offensive.”[66] Cox, “Kursk Offensive.”[67] Boyer and Becker, “Kursk.”[68] Clausewitz, Vom Kriege, 208.[69] Ibid., 347.[70] Ibid., 233.[71] Ibid., 235.[72] Ibid., 350; see also Paret, “Clausewitz,” 208; Stone, Military Strategy, 10; and Watts, “Future War,” 28, 84, for further discussion of soldiers’ combat effectiveness in Clausewitz’s thought.[73] Clausewitz, Vom Kriege, 262.[74] Ibid., 262, 350. [75] McMullen and Rogers, “Remagen.”[76] Ibid.[77] Ibid.[78] Scheller was subsequently court-martialed and executed for failing to destroy the bridge, see Janta, “Exekution,” 199–200.[79] Paret, “Clausewitz,” 208.

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Picture credit: 
Alfred R Waud: Winter Campaigning. The Army of the Potomac on the move (1863)