Where to begin? Authors felled forests in pursuit of analyzing On War, the seminal work of Carl von Clausewitz. Renowned strategic thinkers in the ages since its publication expanded on, clarified, or critiqued its insights into the conduct of war. In this light, the vast collections of materials associated with On War hardly seem to call for another addition to their midst. What else is there to say?
As it turns out, there is a great deal to discuss with one particular group – first-time readers of the classic. While plenty of specialized sources for experts exist, few offer an introduction suitable for the earnest novice. Of course, those especially committed to the study of On War benefit from the range of advanced sources; however, even the most intrepid scholars need a starting point. Herein lies the goal of this essay – offering a primer to On War suitable as a first step. Such a step does not consider each idea offered up in the classic’s pages nor does it examine every scholar who weighed in on the major debates; rather, it highlights the essential concepts most closely associated with this influential work and outlines the larger debates surrounding them.
This essay follows a roadmap especially designed for new readers of On War. After a brief sketch of Carl von Clausewitz’s life, it explores central arguments from the classic in some detail; I choose each topic to advance the fluency of new strategic studies students on often-cited Clausewitzian concepts. The essay proceeds to examine a sampling of scholarship from the vast body of work analyzing the classic with an eye toward giving readers a chance to explore howOn War fits into the broader strategic studies literature. Finally, the essay concludes with suggestions for how to build from this foundation in future studies. None of these are simple tasks given the richness of Clausewitz’s writing, but each is approached with the aim of making this important work of strategy more accessible to first-time readers.
The Man Behind On War
It seems the examination of the Carl von Clausewitz’s life and On War never goes out of style. Indeed, from the moment his treatise on the conduct of war was published, the man behind the ideas was increasingly the subject of study. To this end, several modern looks at the Clausewitz offer comprehensive coverage of his career and the experiences that informed his thinking about war. For the purposes of introducing On War to new students, however, we need only consider a few features of this military-man’s life.
Clausewitz was born on 1 July 1780 in Burg, Prussia, today a part of modern-day Germany. He joined the Prussian army as a teen and fought against France as its revolution spilled across Europe. After service in the field, he studied under Gerhard von Scharnhorst at the Institute for Young Officers in Berlin where his notions on the nature of war and strategy began to earnestly develop began to develop earnestly. Young Clausewitz, alongside Scharnhorst and other forward thinking officers, next went about reforming the Prussian military, including advocating for mass enlistment to combat Napoleon’s French Empire. Prussia was ultimately defeated and compelled to fight alongside France; however, Clausewitz fled east where he offered his services to the Russian army as it defended against Napoleon’s subsequent invasion. Following the failed French campaign in Russia and the defection of Prussia from France, Clausewitz returned home to serve as the chief of staff in one of the Prussian army corps that ultimately helped defeat the French emperor. Following the war, the now distinguished officer served as head of the Military Academy in Berlin where he found the time to pen On War. Clausewitz died in 1831 while serving as chief of staff to the Prussian army, his treatise examining war unfinished.
On War reflects the evolving views of Clausewitz regarding the nature and fighting of war, and it is largely informed by his understanding of the Napoleonic era. Its age does not disqualify the work, and in fact the book remains essential reading for students of strategy. Indeed, today it is one of the most carefully considered works of military strategy in history and military academies and universities around the world include it among their essential readings. On War continues to inform not just the conduct of war, but also a wide range of activities in which strategy broadly defined is paramount, business not least among them. Clausewitz’s influence on Western militaries since his death is firmly established, and the ideas set forth in On War have been and remain influential; however, just how to interpret them is no easy task. The tendrils of confusion may easily wrap themselves around those new to this nuanced text.
On War as a Study
Theory and a Peculiar Trinity
Any new reader of On War needs a few words of warning before opening its pages. First is the issue of completeness. In short, the book is unfinished. Written over twelve years of Carl von Clausewitz’s life, it was left incomplete when he died of cholera before finalizing revisions. As a result, some ideas, most importantly the concept of “absolute war,” vary depending on the chapter under consideration. Of all eight Books included in the final product, Clausewitz only had time to completely revise the first few chapters of Book One. Thankfully, his most important concepts are introduced here and may be used as a guide to decipher later selections. Second, the Prussia strategist employs a dialectic analysis, most clearly on display in the very first chapter of On War. Dialectic analysis essentially uses two competing arguments to get at the underlying nature of a problem. One position is heartily argued before a second argument is employed to replace or amend the first with the aim of uncovering some more fundamental truth. Often used by philosophers, this style of inquiry can be challenging to decode for first time readers. In the case of Clausewitz, this form of analysis has long been the root of several misinterpretations of his work.
On War is seemingly contradictory and scattered not just because it was left unfinished but also because it was originally written in German and has since been translated to English. Translations of disparate quality serve to confound readers and undermine important concepts offered up by the Prussian officer; however, reading a scholarly edition of the book helps mitigate this issue. To this end, the most commonly used edition in the academic study of On War is the 1976 Princeton University Press version, edited and translated by renewed scholars Michael Howard and Peter Paret. Other printings may be cheaper or easier to obtain, but this edition ensures a high-quality translation, and its intuitive editing and formatting help break down at least a few barriers to entry.
From an epistemological perspective, meanwhile, On War employs a particular view on the utility of theory in the study of war, and it is this view that informs the underlying goal of the entire work. Clausewitz argues that theory “is meant to educate the mind of the future commander, or, more accurately, to guide him in his self-education, not to accompany him to the battlefield.” This classical understanding theory is distinct from the scientific conception common in the social sciences today that stresses explanatory and predictive power. Indeed, Clausewitz calls this modern vision of theory into question when he claims that “theory cannot equip the mind with formulas for solving problems, nor can it mark the narrow path on which the sole solution is supposed to lie by planting a hedge of principles on either side.”
The Prussian strategist is responding most directly to strategic notions peddled by what he called the “scribblers of systems” who were interested in mathematical explanations for winning battles. Antoine-Henri Jomini, a contemporary of Clausewitz, was one of the targets against which the Prussian fired this comment and others like it.J omini was famous for appropriating the language of mathematics to proscribe “general principles” from which strategy might be derived, and after the death of Clausewitz, he was the primary critic of and counterpoint to On War. From Clausewitz’s viewpoint, the uncertain nature of war, its fickle inputs, the interaction between combatants, and the human factor undermine any hope for scientific theories of war. From this perspective he launched his own examination of war.
It begins with a definition. Succinctly, war is “an act of force to compel our enemy to do our will.” War is not some primal explosion of violence, although both emotion and violence play an important role, but rather “war is a continuation of political intercourse, carried on with other means.” Importantly, a “political object” motivates war.This is both a subjective and objective statement – it is what war should be and what really differentiates war from fits of violent rage. And from this conceptualization of war several implications flow. Chief among them is that war is a “true political instrument,” that is to say war is itself an act of politics. Meanwhile, the political object, the thing animating a fight, informs the military objectives and the level of effort to achieve these. The political object and the military objectives may be the same, but they are generally different. Regardless, high-quality military objectives are those whose attainment ultimately supports achieving the political object.
Clausewitz’s argues that policy “will permeate all military operations, and, in so far as their violent nature will admit, it will have a continuous influence on them.” Generals do not have the final say on issues of strategic importance; rather, policymakers may exercise their influence at all levels of the military activity as they see fit. The generals work for the policymakers, not the other way around, and military leadership are beholden to interjection from those holding office. Still, both statesmen and commanders must make the same important judgment, namely, determining “the kind of war on which they are embarking; neither mistaking it for, nor trying to turn it into, something that is alien to its nature.” In other words, leadership must determine the scale and characteristics of a war before they subsequently plan to fight it. This determination will influence the strategies employed, conception of the enemy’s center of gravity, level of effort, and a host of other considerations that weigh on the commander, political leadership, or most often both.
War in the service of policy or as an extension of politics might suggest the undertaking is supremely rational. This is only partly true. Clausewitz does explain that “war is not an act of senseless passion but is controlled by its political object” and “the value of this object must determine the sacrifices to be made for it in magnitude and also in duration.” Thus, there is a certain level of rational calculation occurring that matches ends with means. Game theorists of today would find this description of war neatly in line with their modern models. However, the Prussian scholar of war caveats his vision for the rationality of war in no uncertain terms:
[i]t would be an obvious fallacy to imagine war between civilized peoples as resulting merely from a rational act on the part of the governments and to conceive of war as a gradually ridding itself of passion so that in the end one would never really need to use the physical impact of the fighting forces – comparative figures of their strength would be enough. That would be a kind of war by algebra…. If war is an act of force, the emotions cannot fail to be involved. War may not spring from them, but they will still affect it in some degree, and the extent to which they do so will depend not on the level of civilization but on how important the conflicting interests are and on how long their conflict lasts.
Thus, emotion (or irrationality) and rationality each have a partial but important influence over the conduct of war. Neither should be neglected but neither completely explains violent armed combat. Additionally, the excerpt above once again highlights Clausewitz’s view on the role of theory in war – those seeking a determinative, mathematical, or purely scientific “war by algebra” miss an essential feature of the phenomena in question.
Beyond the roles of politics and emotion in war, Clausewitz introduces a third central feature – chance, or nonrationality. Because a commander is forced to assess probabilities “in light of the circumstances” that she faces, there is a natural, non-deterministic feature to war. “No other human activity is so continuously or universally bound up with chance,” argues the Prussian officer. While strategy, training, and planning may mitigate this consideration, it is an ever-present and unavoidable aspect of warfare. Chance ultimately makes engaging in war something of a gamble. Nothing is known for certain, and how the many actors engaged in a fight might break upon one another, work amongst themselves, or understand the progress of the conflict are all subject to chance.
This all leads to what Clausewitz calls war’s “trinity.” Standing on three legs, he contends that war is characterized by:
 primordial violence, hatred, and enmity, which are to be regarded as a blind natural force;  of the play of chance and probability within which the creative spirit is free to roam;  and of its element of subordination, as an instrument of policy, which makes it subject to reason alone.
The Prussian officer attaches each of these legs to a particular constituency engaged in war. The first, violence, deals principally with a people at war. While wars may not spring to life because of blind passion or rage, the citizenry enlisted to support and fight in wars certainly falls to these base emotions. The second, chance, deals mostly with military leadership and the armies they command. Commanders may exploit or fall prey to chance and probability depending on how well they craft their strategy. Finally, policy is most associated with the government waging a war. It is on political leaders to exercise their control over military activities and to sync them with the ultimate political end of the war. Together these three features form a trinity that embodies war; however, there is an important caveat. Just because one group is associated with a particular leg in the trinity does not mean it cannot experience something of the other two. Governments may run into chance. Militaries may come to know rage. The trinity is not cleanly one-for-one with constituencies. Reality is more malleable.
War in Theory, War in Reality
The relationship between absolute war, what Clausewitz also called war in theory, and limited war, or war in practice, confuses many first-time readers of On War. Significant portions of Book I and Book IV, among others, discuss absolute war at some length. In short, absolute war is what would result from merely following the logic of combat to its rational conclusion – application of maximal violence. It is a theoretical type of politically motivated combat whose logic is characterized by three “extremes” featuring “interaction” between combatants. Interaction is best understood as an action-reaction dynamic that develops between competitors. One side takes some action and the opposing side reacts to this action only to have the first side react in turn to the latest reaction and so on. It is the same type of reasoning that motivates many game theoretic inquiries in the social sciences today and is essential to understanding absolute war and the three “extremes.”
The first extreme associated with absolute war and the first source of interaction resides in the use of force itself. Clausewitz argues that “war is an act of force, and there is no logical limit to the applications of that force” each side may apply attempting to defeat an opposing military in pursuit of a political objective. What is the rational extension of this dynamic? Each side employs maximal force. The second extreme contends that each side in war shares the same fundamental aim – to completely disarm or overthrow its opponent. Only after this is complete can the victor attain a political objective. So long as each opponent remains in the field, neither is in complete control of the war’s outcome, and both are driven to the same second extreme. Finally, each side in a war adjusts its level of effort to match the other. Because this is a dynamic interaction and each side holds the same basic aim, the level of effort on each side will logically be driven to the maximum. This is the third and final extreme. Because all three extremes work in combination, absolute war represents a type of warfare characterized by massive mobilizations, enormous battles, and war until the complete subjugation of one side or the other.
While the notion of absolute war anchors the opening pages of On War, but it is hardly Clausewitz’s final assessment of his subject; indeed, it is just a starting point for a dialectic inquiry into the nature of war. Students must ultimately understand how reality in fact modifies war in theory. Failing this modification, even the most dedicated readers easily misunderstand the classic treatise on war and strategy. Clausewitz sets up absolute war as an “ideal type,” a theoretical form of conflict that is never actually observed in the world for three reasons. First, “war is never an isolated act” but rather a series of moves and countermoves in which both sides participate. Commanders on each side may thus adjust their plans in accordance with what their opponents actually do over time rather than what they ought to do in theory. Second, “war does not consist of a single short blow.” Instead, it is often characterized by a series of smaller ones. After all, time and space present obvious logistical challenges making it impossible to concentrate forces on each side at precisely the same moment and in the same location to fight a war in a single massive battle. Finally, “in war the result is never final,” meaning that it may be re-adjudicated in the future. Those defeated may fight again on another day to reclaim some loss. All told, these three mitigating factors prevent war from ever reaching its theoretical extreme. Absolute war exists only in the minds of theorists, not of the fields of battle. War in reality is limited.
Combat, Defense, and Strategy
Even if war does not reach its logical violent extreme, it does remain a bloody business. Clausewitz takes a strong position on the centrality of combat in war. He argues that “it is inherent in the very concept of war that everything that occurs must originally derive from combat.” As a result, “the whole of military activity must therefore relate directly or indirectly to the engagement,” which is to say, preparing to meet the enemy in battle becomes the central purpose of strategy. In his most vivid description of combat Clausewitz writes:
Battle is the bloodiest solution. While it should not simply be considered as mutual murder – its effect is rather a killing of the enemy’s spirit than of his men – it is always true that the character of battle, like its name [Schlacht] is slaughter, and its price is blood.
While this is perhaps a startling view, the Prussian took it quite seriously. Indeed, from his perspective, it is actually foolhardy to think that war might be fought without the loss of blood and these types of errant hopes, given the stakes of war, are the very worst.
Still, it is possible to misunderstand the implications of Clausewitz’s position. Pursuing combat may be the only way to prosecute a war, but that does not necessarily mean combat always occurs. While “combat is the only effective force in war,” Clausewitz makes clear that “its aim is to destroy the enemy’s forces as a means to a further end.” Combat is not the end in and of itself. Thus, fighting may not necessarily come to pass. Why? It is “because the outcome rests on the assumption that if it came to fighting, the enemy would be destroyed.” If an enemy knows he will be defeated in a fight, he may not risk the death and destruction and instead leave open the path to achieving the political objective without a fight. This is a subtle nuance, easy to miss if a reader gets hung up on the notion of battle itself.
Additional nuances mark the concept of combat. For instance, not all forms of combat are equal. Rather, Clausewitz argues that there are “two distinct forms of action in war: attack and defense.” He goes on to maintain that “the defensive form of warfare is intrinsically stronger than the offensive.” This does not mean that a commander merely digs his men in and waits for his opponent to attack. Rather, defense is relative. A wise military commander might employ offensive strikes as part of a wider defensive war; for example, “a defensive campaign can be fought with offensive battles.” Still, the defense should only be employed until an army is strong enough to attack, since it is the offense that achieves the “positive aim” of war, namely the military objective in support of a political object. Once the defense degrades an enemy and yields a more favorable “balance of strength,” only the offense can be used to win a war.
If combat is central to war, how is strategy employed to meet in battle on the most favorable terms? Indeed, this is the question many students of strategy are most interested in answering. Book III is entirely devoted to discussing the details of sound strategy. Clausewitz defines strategy as “the use of the engagement for the purpose of the war.”Several elements of strategy ultimately affect the engagement, including “moral, physical, mathematical, geographical, and statistical” considerations. Of these the most important may be the moral. It is made up of the “skill of the commander, the experience and courage of the troops, and their patriotic spirit.”Additionally Clausewitz suggests that the very best strategist will “define an aim for the entire operational side of the war that will be in accordance with its [political] purpose.”
Designing a strategy may be simple in theory, matching military means with political ends, but executing one is a challenge suitable only for a commander who has “great strength of character” and who has the “firmness of mind” necessary to see a strategy through to completion. The human factor becomes essential to effective strategy, and it is here that the concept of “genius” comes to the fore in On War. To Clausewitz, genius does not suggest anything about the intellectual capability of a commander. While traditional smarts might be useful, they do not constitute the makings of a great captain nor do they ensure that such a leader can establish or carry out a successful strategy. When speaking of military genius Clausewitz has other characteristics in mind. First, the courage to act in the face of danger and to accept responsibility for the prosecution of a campaign are essential for the commander and ideally she holds “a compound of both.” Second, there must be a “strength of body and soul” to see a commander through the suffering of war.Third are the “powers of intellect” characterized by a “sensitive and discriminating judgment” for cutting to the truth of a matter.Together, these constitute genius.
The first and third features, courage and the ability to perceive truth, are essential for any military commander given the “relentless struggle with the unforeseen,” or chance, that surrounds combat. But the ability to find truth is not enough; indeed, the courage to pursue it, embodied in a “strong rather than a brilliant” mind is essential. Here an element of instinct becomes important. Throughout Chapter 3 of Book I Clausewitz goes into even greater detail about the making of military genius. He ultimately concludes that the ideal commander embodying this characteristic will have an “inquiring rather than the creative mind,” “the comprehensive rather than the specialized approach,” and finally “the calm rather than the excitable head.” This is the man or women who can be trusted to lead an army.
Victory in War
One of the most difficult concepts to grasp in On War is the “center of gravity.” Sometimes abbreviated as CoG for short by military professionals, is a term Clausewitz uses repeatedly throughout his classic but in varying ways. In fact, rarely does he use it to describe precisely the same thing more than once. Consequently, it is an easy place for confusion to degrade understanding. One way to approach this concept is to accept the multitude of meanings as they come. While it is impractical to review each mention in detail, indeed an entire paper could easily be written on just this concept, some references are sufficiently congruent to serve as a starting point. Exploring the center of gravity also begins to give a sense for how wars may be won.
In his Book IV chapter on battle, Clausewitz writes that “since the essence of war is fighting, and since the battle is the fight of the main force, the battle must always be considered the true center of gravity in war.” He goes on to argue that “the major battle is therefore to be regarded as concentrated war, as the center of gravity of the entire conflict or campaign.” In this conceptualization, the center of gravity is something akin to the enemy’s forces, the point against which an attack is launched, and battle that occurs at this point. It is an understanding naturally flowing from Clausewitz’s arguments about the centrality of combat. Later in Book VI this vision seems extended, if just slightly. Clausewitz writes that “a center of gravity is always found where the mass is concentrated… [i]t presents the most effective target for a blow.” Here Clausewitz seems to suggest that the center of gravity is not just a target for attack, but rather the point where the greatest benefit from attacking will be realized. Finally, in his last Book, the Prussian strategist expands the meaning to the most general strategic perspective. Here he writes that the center of gravity is “the hub of all power and movement, on which everything depends.” Now it might include leadership, a capital city, or an essential ally rather than just an opposing military force. New readers of On War should take careful note of this last, broader definition.
Beyond the center of gravity, two additional concepts especially associated with Clausewitz have bearing on the termination of war – the “culminating point of attack” and the “culminating point of victory.” Though the defense is viewed as stronger than the attack, it is often the offense that wins a war through attaining the “positive aim.” These attacks may offer gains to the side employing them provided they do not go beyond the “culminating point of attack,” the point at which the commander has pressed an attack so far that his remaining strength is just enough to defend the gains won. At this point the strength of the defense can be used to hold the winnings resulting from the offence. Should a commander push beyond this point, the counterattack from the opponent will drive him back resulting in the loss of any gains made in the initial attack. A wise commander must therefore “detect the culminating point with discriminative judgment” so as to not step beyond it. If this is possible, the gains from the initial attack may be held and affect the negotiations at the end of the war.
The “culminating point of victory”, meanwhile, is a similar but distinct concept. Clausewitz writes that “… it is not possible in every war for the victor to overthrow his enemy completely,” as would be the case in theoretical, absolute war; instead, “even victory has a culminating point.” Generally the side with superior strength, especially numerical, wins the victory.Superior strength allows a commander to seek complete destruction of his opponent or at least take steps to improve positioning for negotiations, perhaps by taking and holding some enemy territory.Yet, superiority is merely the means to an end. When the enemy cannot be destroyed outright, a commander should not press beyond the point where gains cannot be defended. The “culminating point of victory” thus takes the dynamic insights of the “culminating point of attack” and applies them to the strategic level. Pushing beyond this point invites the possibility of damaging one’s position in negotiations since any additional gains would only be lost to an opponent’s reaction.
All three of these concepts offer insights into the dynamics of victory and war termination, yet formalization of this process remains. Book I of On War offers the clearest insights along these lines and proposes three distinct paths to victory. The simplest and most preferred by the old strategist aims to “bring about the enemy’s collapse – the destruction of his armed forces and the conquest of his territory.” This is the surest way to achieve the political object held in the balance of war, and Clausewitz outlines the logic behind this approach in the introduction to chapter eleven of Book IV. In short, the destruction of enemy forces is the chief means to achieve the political object in war and fighting is generally the only way to bring about this destruction. Thus, the greatest successes toward achieving the goals of a war are won in major engagements, ideally in “one great battle” aimed at the enemy’s center of gravity. While this is theoretically easy to understand, it is not always possible in reality, as discussed earlier.
The second path to victory centers on adjusting the probability of winning. Of course increasing the probability for one side naturally decreases the probability for the other since it is a zero-sum game between two combatants. Clausewitz observes:
Not every war need be fought until one side collapses. When the motives and tensions of war are slight we can imagine that the very faintest prospect of defeat might be enough to cause one side to yield. If from the very start the other side feels that this is probable, it will obviously concentrate on bringing about this probability rather than take the long way round and totally defeat the enemy.
He goes on to discuss specific ways these probabilities might be altered:
It is possible to increase the likelihood of success without defeating the enemy’s forces. I refer to operations that have direct political repercussions, that are designed in the first place to disrupt the opposing alliance, or paralyze it, that gain us new allies, favorably affect the political scene, etc. 
While combat and battle might offer the surest theoretical route to success, in reality, altering the probabilities for success will matter a great deal in determining if one party will still keep up the fight. The concepts of the “culminating point of attack” and the “culminating point of victory” play a role in this vision for war termination since an enemy dug in and defending from the culminating point of victory sends a clear message that the odds of winning the war have settled in its favor.
The last path to termination centers on making continued war an unacceptably high cost for one’s opponent.Costs may be increased four ways, though the magnitude of each varies given the natures of the combatants and governments involved. The first is the “wastage of his forces” and conquest, or permanent holding, of his territory. Second is invasion and “seizure of enemy territory” not with the aim of holding it indefinitely but rather to gather financial resources at the enemy’s expense or to “lay it waste” so that the enemy cannot benefit from it. Third “is to wear down the enemy,” meaning to use “the duration of the war to bring about a gradual exhaustion of his physical and moral resistance.” And finally, one may simply drag the war out by waiting for the enemy to attack, refusing engagements except only those on the most favorable defensive terms. This last method will not secure any major political object, but it certainly can help achieve a minimal object of political survival. Regardless of how costs are amplified, an opponent engaged in a cost-benefit analysis may reconsider ongoing participation in a war under these circumstances.
In a sense, each of these alternatives paths to victory corresponds to one of the legs in the trinity: outright destruction of the enemy might be the outcome of hatred and violence, altering the probabilities of success plays in the world of chance, and forcing new cost-benefit analyses relies on the rational government. Still, the alternative paths to victory are often lost on readers of On War, though this is understandable since they are buried in the classic and hardly receive the same coverage as victory through battle. The importance of battle is ultimately the thing most closely associated with Clausewitz. A particular quote from Book IV is often cited to support this narrow view:
We are not interested in generals who win victories without bloodshed. The fact that slaughter is a horrifying spectacle must make us take war more seriously, but not provide an excuse for gradually blunting our swords in the name of humanity. Sooner or later someone will come along with a sharp sword and hack off our arms.
A second is also often quoted:
Kind-hearted people might of course think that there was some ingenious way to disarm or defeat an enemy without too much bloodshed, and might imagine that this is the true goal of the art of war. Pleasant as it sounds, it is a fallacy that must be exposed: war is such a dangerous business that the mistakes which come from kindness are the very worst. The maximum use of force is in no way incompatible with the simultaneous use of the intellect.
Yet, Clausewitz provides clear visions for victory that do not entail bloodshed alone. What should be made of this seeming contradiction? Returning to the text of Book I is essential. It is this text, after all, that was subject to the most revisions before its author’s untimely death. And in its pages readers find all three recipes for alternative endings to war. Perhaps the compromise view, the view most closely representing that of Clausewitz at the end of this life, might be this: though there are alternatives to complete destruction of the enemy that might lead to attainment of a political object, the most certain way to achieve a political end is through successful battle.
Constant and Changing Features of War
While this essay does not address every insight into war offered by Clausewitz, it does aim to cover the most essential. Two of these are the “fog of war” and “friction.” Each contributes to the presence of chance in war, and they pose universal challenges and opportunities to commanders. Importantly, both are constant features of combat, timeless features of war that remain as relevant today as they did in the 19th century.
Clausewitz writes that “war is the realm of uncertainty; three quarters of the factors on which action in war is based are wrapped in a fog of greater or lesser uncertainty.” The “fog” to which he refers is known as the “fog of war,” and in his discussion of military genius, Clausewitz stresses the importance of sound intuition and the ability to discover truth as essential characteristics of a commander who will operate effectively in this fog. This insight into the uncertain and hazy features of war has profound implications for the utility of military intelligence in war. From the viewpoint of Clausewitz “most intelligence is false, and the effect of fear is to multiply lies and inaccuracies.”Intelligence reports often do not help cut away the fog, but rather they compound it by spreading misinformation or disinformation. Thus, it is even more important for a commander to have the genius necessary to divine truth out of the fog. But truth will not come along easily.
The fog of war, meanwhile, is just one source of friction. “Everything in war is very simple, but the simplest thing is difficult. The difficulties accumulate and end by producing a kind of friction,” observes the old Prussian strategist.In some ways the concept of friction is akin to Murphy’s Law – everything that can go wrong will go wrong at some point or another during war. Weather might gum up transportation. Mechanical failures might delay an offensive. Disease might render large swaths of troops unfit for duty. These are all examples of friction, and it is friction “that more or less corresponds to the factors that distinguish real war from war on paper.” Friction is one brake preventing the dynamics of war in theory from being realized in reality. Ultimately, Clausewitz links friction to the behavior of a high-quality commander and the preparation of the army. A leader “must know friction in order to overcome it whenever possible, and in order not to expect a standard of achievement in his operations which this very friction makes impossible.” Meanwhile an army especially well trained or exercised may minimize friction. As the peculiar trinity reminds us, war is in part governed by chance, and it is friction, along with the fog of war, from which this element of chance springs.
If war is intimately wrapped up in these constant features, how does Clausewitz view the undoubtable changing features of war? After all, over time there are many changes in the tactics and technologies that animate war, and say war remains characterized by static broad features seems out of place when considering the diversity of armed conflict. The Prussian strategist thus differentiates between what he calls the “logic” and the “grammar” of war. The logic of war is the timeless part. All wars are fought as a continuation of politics, for the achievement of political aims, and this continues, “irrespective of the means it employs.” The “grammar” of war includes all the ways that it is prosecuted. Indeed, this grammar may be unique to a particular war or a particular period in time, but it remains subordinate to the logic of war. If it does not, if the violence states wreak on one another decouples from political aims, then such violence is “pointless and devoid of sense.” Ultimately, Clausewitz is well aware that features of war change with time, but just because wars may appear different or be fought using different means it does not mean that they are fought for different purposes. The purpose of war, just like the fog of war and friction, remains enduring.
A Special Kind of War, “People at Arms”
While Clausewitz is primarily occupied with discussing war between states using conventional armies and weapons, he does devote one chapter of On War to the question of what he calls “people at arms.” By this he means instances where civilians rather than professional soldiers engage in fighting, or, more specifically, insurrection. The brief chapter addressing this type of warfare envisions insurgency standing alongside or as an auxiliary to conventional warfare. “One must therefore think of a general insurrection within the framework of a war conducted by the regular army, and coordinated in one all-encompassing plan,” writes Clausewitz. From this starting point his thesis is simple, namely “any nation that uses it [people’s war] intelligently will, as a rule, gain some superiority over those who disdain its use;” yet, features of this thesis and the logic underpinning it require elaboration.
First is the question of resources. While Clausewitz understands why some might argue for applying the resources of an insurrection toward other military efforts, he retorts that many of these resources are unique, indeed “called into being only by this type of usage,” and consequently cannot be turned toward other types of warfare. A passionate regular citizen, willing to bend her resources against an enemy operating in the territory of her state, is positioned to engage in activities unlike those of regular forces. At her disposal are resources, especially the passion of everyday people, and opportunities, including access to enemy supply lines, communications hubs, and staging areas, unique to her circumstances and environment that cannot easily translate to other kinds of warfare. An insurgency, therefore, should not be opposed by commanders on the logic of resources; rather, insurgency should be appreciated for bringing new opportunities to the fight.
The second caveat focuses on the types of operations in which a people at arms may engage. Here Clausewitz is somewhat poetic: “Like smoldering embers, [insurgency] consumes the basic foundations of the enemy.” This is to say, insurgents are best at offering “scattered resistance” designed to wear down an enemy over time rather than fighting “major actions.” Militia forces or civilians practicing insurgency “should not be employed against the main enemy force” and instead gather around the enemy like “thunder clouds” harassing small units of the enemy and aiming always to “nibble at the shell and around the edges” of powerful enemy armies.< In the same vein, an uprising must be “nebulous and elusive” so that the enemy cannot “direct sufficient force at its core, crush it, and take many prisoners” for in these instances a people at arms will “lose heart” and give up their efforts.
When it comes to just how insurgents should “nibble at the shell,” Clausewitz offers definitive advice. He urges that the strongest insurgent forces should focus their activities on the flanks of an enemy and most importantly on its rear where the greatest psychological damage may be realized. Under no circumstance should irregular forces find themselves in a pitched battle or defending against regular forces for in these instances the likelihood of loss is far too high to justify the risk; better to scatter apart and engage in surprise attacks than face annihilation. The aim of a people at arms is always to weaken their opponent, setting up a more favorable fight between their conventional brothers-at-arms and the enemy.
Clearly Clausewitz is much more interested in how to employ a people at arms rather than fight against them. This raises the third point. Under what circumstances should people at arms be employed? The Prussian military thinker lists five conditions under which a general uprising may be effective. First, the war in question must be carried out throughout the inside of a country, not along its borders. Only there will the enemy be sufficiently surrounded by the populace to face real risks from an insurgency. Second, the war must not hinge on a single battle but rather be drawn out over time to give insurgents an opportunity to disrupt and dishearten the enemy. Third, military actions must take place over a relatively large theater of operations throughout which insurgents may move, attack, and hide. Fourth, the civilian people themselves must be suited to engaging in armed resistance. Insurgencies are only as good as the people willing to fight in them. And fifth, a country with rough features, including mountains, forests, marshes, or other natural barriers offer insurgents the protection needed to mount their attacks and hinder the rapid and effective use of regular forces. There is also the question of when in time an insurgency may be best suited. Here Clausewitz suggests that insurgencies may be useful as a last resort after a major defeat or “as a natural auxiliary [to regular forces] before a decisive battle.”
The fourth and final highlight surrounding Clausewitz’s treatment of insurgent warfare is how he expects the enemy to respond to threats on his flanks, at his rear, and across the territory in which he attempts to operate. Simply, “the enemy’s only answer to militia actions is the sending out of frequent escorts as protection for his convoys, and as guards on all his stopping places, bridges, defiles, and the rest.”By doing so he opens himself up to additional attacks, expends precious resources on basic needs, and spreads his troops thin across the theater of operation. All of this serves to speed the enemy’s ultimate destruction by regular forces at some point in the future. Clausewitz’s own words drive this point home:
Once the victor is engaged in sieges, once he has left strong garrisons all the way to form his line of communication, or has even sent out detachments to secure his freedom of movement and keep adjoining provinces from giving him trouble, once he has been weakened by a variety of losses in men and materiel, the time has come for the defending army to take the field again. Then a well-placed blow on the attacker in his difficult situation will be enough to shake him.
On War is neither a classic for the study of insurgency nor counterinsurgency. Its treatment of approaches to fighting against a people at arms is especially scant. The reason Clausewitz remains relevant to the study of insurgent warfare has to do with how well he presaged insights from future strategists like T.E. Lawrence, Mao Zedong, and others. His arguments about the importance of terrain to insurgents, his stress on the need to keep irregular forces scattered, his understanding of the psychological strain placed on the counterinsurgent, his appreciation for the importance of a prolonged war in successful insurgencies, among other ideas, are all early attempts to grapple with a decidedly different “grammar” of warfare that would ultimately preoccupy many modern armies. By his own admission, at the time of Clausewitz’s writing insurgent warfare was uncommon and little studied. Yet, a founder of Western military strategy picked up his pen all the same and turned it toward the task, if only briefly. Such was his foresight and such was his conviction that war, regardless of the form it takes, was ultimately governed by a universal “logic.”
The Study of On War
The incomplete status of On War left its author conflicted. On one hand he issued a stern warning. A note found amongst the papers of his draft cautioned that “should the work be interrupted by my death, then what is found can only be called a mass of conceptions not brought into form… open to endless misconceptions.” Yet his prefatory note to the manuscript, dated July 1827, suggests a different vision:
Despite the manuscript’s incomplete form, I believe an unbiased reader, who thirsts after truth and conviction, will not fail to recognize in the first six books the fruits of many years of considering and diligently studying war; perhaps he will even find in them the principal ideas from which a revolution in military theory might emerge.
Unfortunately, it seems few unbiased readers picked up On War throughout history. As Michael Howard puts it, “Clausewitz, as it turned out, had less cause to fear his critics than to be wary of many of his professed admirers” since they often selectively quoted the Prussian strategist’s writings to suit their own arguments. This spotty, loaded treatment of the classic proved to be a source of confusion for centuries. Thankfully, there are several scholars who might be relied on to help navigate these difficult straits even as they offer their own analysis and critique of the Prussian strategist.
One of the foremost authorities on military strategy today is Colin Gray, and in his own studies, Gray liberally refers to and helps put into perspective several of Clausewitz’s central ideas. Gray, like Clausewitz, believes that “there are elements common to war and strategy in all periods, in all geographies, and with all technologies,” and consequently the modern scholar sees himself writing in the same tradition as the Prussian staff officer. In many ways, Gray is largely neo-Clausewitzian, clarifying and showing the universality of the ideas developed in the early nineteenth century. He certainly argues for the centrality of policy as the guiding force behind military power. Additionally, he lauds Clausewitz’s insight into the role of chance in war as relevant today just as it was in the past.< The notion of friction likewise remains a central aspect of war. These timeless features, argues Gray, are ignored at the peril of modern commanders.
Still, Gray does diverge from Clausewitz in some subtle ways. While he admits that the purpose of war may be to “impose our will on the enemy,” he argues that force is not the sole instrument of strategy; rather, “diplomacy, propaganda, cultural subversion and demoralization, trade embargoes, espionage and sabotage can all have a strategic effect” and play a role in winning victory. He also points out shortcomings in the writings of Clausewitz that modern history has laid bare. Gray writes that “Clausewitz offers little help to educate the policymaker or the military commander for their mutual dealings” even as the Prussian is “eloquent on the subject of the political instrumentality of war.” Such education is left to other strategists, it would seem. Still, scholars like Gray who build on the foundation of Clausewitz continue to show not just the continuing academic relevance of On War, but just how important its ideas are for the conduct of war today.
Not all modern analysts are so complementary of Clausewitz. British strategist B. H. Liddell Hart, one of the foremost strategic thinkers of the twentieth century, argues forcefully that not only is Clausewitz wrong about a great many aspects of war, but his confused writings were the cause of calamitous death during World War I and World War II. At least five major criticisms of On War are offered in Hart’s own major work on strategy. First, Hart contends that Clausewitz vastly underestimated the utility of sea-power in war. The Prussian writes nearly nothing about the use of navies in the pursuit of military victory. Second, Clausewitz overemphasizes the importance superior numbers in achieving victory, and it is this overestimation that helped kill so many in the trenches of the Great War. Third, On War’s author “was carried away by a passion for pure logic,” especially as it related to war in theory. Fourth, Hart claims that Clausewitz harmed history with the statement that only bloodshed can overcome an enemy, even if he qualified the notion in other portions of On War. An easy idea to remember, it was often picked up on by casual readers of the classic and used to ill effect on the fields of battle. Finally, Hart argues “worse was the effect of his theoretical exposition, and exaltation, of the idea of ‘absolute’ warfare – in proclaiming that the road to success was through the unlimited application of force.” To be fair, the British strategist does acknowledge that Clausewitz attempted to differentiate between theoretical war and war in reality; however:
… it was the ideal, and not the practical, aspect of his teaching on battle which survived. He contributed to the distortion by arguing that it was only to avoid the risks of battle that ’any other means are taken’. And he fixed the distortion in the minds of his pupils by hammering on the abstract ideal.
While aspects of Hart’s critiques are overblown, for example he often confuses misinterpretations with the text itself, his views form the foundation for ongoing criticisms of Clausewitz.
Perhaps the very best writings analyzing On War, however, appear in the 1976 edition of the book edited by Michael Howard and Peter Paret. Howard and Paret, joined by well-known strategist Bernard Brodie, collectively offer three introductory essays and one follow-on guide that do an admirable job placing the book, its author, and its major ideas into context suitable for a new student of strategy. Howard explains the enduring influence of Clausewitz on the conduct of war while Parrott walks through the origins of the book and the history poured into it. Brodie, not to be outdone, takes on double duty. After making the case for the continued relevance of On War, he crafts a book-by-book, chapter-by-chapter guide to the entire work that distilled the major themes and concepts of each section down into a brief overview. While certainly suppressing the color of each chapter, the guide succeeds in offering a digestible abridged introduction to the text that makes some of its more challenging portions easier to understand. Indeed, had earlier readers had access to these materials, many of the misinterpretations so chastised by Hart may not have come to pass.
Because On War is such a central book to Western strategy and offers so many insights into the nature and conduct of war, it continues to receive critical consideration by scholars publishing today. One of the more prolific has been Hew Strachan. Of the many points Strachan raises, one of the most thought-provoking centers on identifying the particular perspective Howard and Paret brought to their translation of On War. He argues that their 1976 translation “gave priority to Clausewitz the rationalist, who stressed the relationship between war and policy” and this particular reading plays up just one of Clausewitz’s many important ideas perhaps to the determent of others and to the confusion of readers. Strachan also takes careful aim at those who outright reject Clausewitz, suggesting that they do so only “on the basis of a selective reading.” Instead, when On War is viewed in the context of Clausewitz’s life, the history of its times, and with a careful eye, it offers subtle, relevant insights into the eternal nature and conduct of war.
Read and Reread
The very tone in which On War is written suggests implicitly what Colin Gray explicitly calls out – Clausewitz viewed strategy as a timeless endeavor. Modern scholars and commanders are often quite taken with seemingly new features of warfare, and revolutions in military affairs driven in part by novel technologies and their creative application are well documented throughout history. However, a hallmark of On War, what makes it still so powerful today, is that it taps into features of war that will not change with the passage of time. The importance of politics, policy, friction, fog, combat – wise strategists have identified these and other concepts championed by Clausewitz as perpetually wrapped up in the experience of war. For this reason, serious students of strategy and diplomacy should commit themselves not just to reading On War once, but rereading it with some regularity. The first time should not be the last time, and rest assured, students who open its pages many times over will consistently find something fresh to consider.
Aron, Raymond. Clausewitz, Philosopher of War. 1st Touchstone ed. New York: Simon & Schuster, 1986.
Aron offers both an analysis of Clausewitz and his major ideas in this often cited work. After tackling the life of the Prussian strategist, Aron considers the central dialectics of war examined in On War, namely means and ends, moral and physical, and defense and attack. He moves on to examine the history that influenced Clausewitz’s views on war and its implications for theory before concluding with what Clausewitz has to offer modern strategists in the nuclear age. A thoughtful and thorough book, this should be read by serious students of strategy.
Brodie, Bernard. “The Continuing Relevance of On War.” In On War, translated and edited by Michael Howard and Peter Paret. Princeton, NJ: Princeton University Press, 1976.
This short essay is an enjoyable read that quickly makes the case for why modern students of strategy ought to read Clausewitz in some detail. Written by one of the foremost strategic thinkers of the 20th century, this is one of the first bits of scholarship that a new pupil to strategic studies should to consider, and it may even be worth looking at before tackling the On War itself.
Brodie, Bernard. “A Guide to Reading On War.” In On War, translated and edited by Michael Howard and Peter Paret. Princeton, NJ: Princeton University Press, 1976.
This is Brodie’s boiled down summary of On War. To be sure details are suppressed, richness of language lost, and subtle implications glossed over, but this serves as a useful reference to students struggling to maneuver Clausewitz’s words on their own terms. While this should not be read as a stand-alone piece, it is a useful guide when used alongside the original text.
Clausewitz, Carl von. On War. Translated and edited by Michael Howard and Peter Paret. Princeton, NJ: Princeton University Press, 1976.
This has become the starting point for most scholars aiming to understand the evolution of Western military strategy. Given its major influence on the development of strategy and enduring relevance, it is still taught in most military schools of higher education and in a wide range of civilian international affairs programs. Sometimes difficult maneuver and often a bit convoluted, it is still a must read for any serious student of strategy.
Echevarria II, Antulio J. Clausewitz and Contemporary War. Oxford, UK: Oxford University Press, 2007.
Antulio Echevarria has long been associated with the U.S. Army War College and is one of today’s leading Clausewitz scholars. This book aims to make Clausewitz’s central teaching relevant to a modern audience. Accessible and easy to read, this source should be used by students seeking to broaden their understanding of Clausewitz’s ongoing relevance and contemporary application.
Encyclopædia Britannica Online, s. v. “Carl von Clausewitz”, accessed January 17, 2016, http://www.britannica.com/biography/Carl-von-Clausewitz.
This is a quick, easy-to-read biography of Clausewitz most appropriate for swiftly orienting students to his life and professional experiences. It is a good place to begin considering his life, but is really just a first step for those interested understanding the man behind On War.
Gray, Colin S. Modern Strategy. Oxford, UK: Oxford University Press, 1999.
Colin Gray is one of the most widely read modern strategists. His work builds neatly on that of Clausewitz, and Gray does a very good job helping make the central ideas of On War relevant and accessible to a modern audience. His Modern Strategy in many ways is a neo-Clauswitzian book that expands on the classic observations of the Prussian officer while amending those that have been confused or misapplied over time.
Hart, B.H. Liddell. Strategy, Second Revised Edition. New York, NY: Fredrick A. Praeger Publishers, 1967.
While not his first attempt at sharing his insights regarding the indirect approach to strategy, it is certainly Liddell Hart’s best known and most relevant. Assigned reading in many strategic studies programs, Strategy is a necessary companion to the study of Clausewitz, Sun Tzu, Moltke, Fuller, and a host of other well-known thinkers on military affairs. While not a flawless book or perfect conceptualization of military strategy, its clear style offers an easy entry point into larger debates on the use of military force.
Howard, Michael. “The Influence of Clausewitz,” In On War, translated and edited by Michael Howard and Peter Paret. Princeton, NJ: Princeton University Press, 1976.
Howard is legendary among the strategic studies and military history communities. Like Paret’s essay on the origins of On War, this short article ought to be read even before reading the classic itself. Not only does it put the Clausewitz’s book in context, it helps explain the importance of the piece to the development of Western strategic thought over many years. This knowledge makes approaching On War easier and more meaningful, especially given the investment of time and energy such a pursuit requires.
Paret, Peter. “The Genesis of On War,” In On War, translated and edited by Michael Howard and Peter Paret. Princeton, NJ: Princeton University Press, 1976.
This brief essay in the opening pages of the Howard and Paret translation traces origins and development of On War. It is a must read piece, useful to look at even before examining the words of Clausewitz himself. Additionally, Paret is an enjoyable thinker to read, making the distant life of the Prussian strategist come alive for new students of strategy.
Strachan, Hew. Clausewitz’s On War, A Biography. New York: Atlantic Monthly Press, 2007.
Strachan’s book, as its title suggests, is a detailed discussion of On War’s development. By putting the book into its historical context and by examining several of Clausewitz’s other writings, Strachan attempts to construct the proper lens through which to read the classic work of strategy. This is an excellent source for students seeking to gain a deeper appreciation for how On Warcame to exist and move beyond the outline provided by Paret in his introduction to the 1976 translation.