On War

”Frequent periods of inaction in war remove it further from the absolute, and make it still more a calculation of probabilities.”

War is punctuated by combat, with alternating periods of troop inaction highlighting the existence of uncertainties and probabilities. Here, Clausewitz underscores one of the many reasons why the generalizations of war theory have limits. His focus on pauses between combat is also significant because it was generally absent from previous war theory.

“War is a mere continuation of policy by other means. We see, therefore, that war is not merely a political act, but also a real political instrument, a continuation of political commerce, a carrying out of the same by other means.”

Clausewitz highlights the strategic role of war in attaining a general political goal. In this framework, war is merely an instrument, when all other instruments may have been exhausted. In this way, combat is directly linked to foreign policy.

“Tactics and strategy are two activities mutually permeating each other in time and space, at the same time essentially different activities, the inner laws and mutual relations of which cannot be intelligible at all to the mind until a clear conception of the nature of each activity is established.”

According to the author, tactics and strategy exist in related but separate realms. Occasionally, they converge, and other times they are separate and distinct. Whereas tactics directly address the use of armed forces in combat, strategy addresses the overarching goal of war, which is often a political aim. It is also important to note that in Clausewitz’s time, “strategy” had a more limited meaning focused on the operational level of war.

“The superiority in numbers being a material condition, it was chosen from amongst all the factors required to produce victory, because it could be brought under mathematical laws through combinations of time and space.”

Numerical superiority is one of the key factors for successful combat. However, it is not the only factor that leads to victory, nor is it a guarantee. The author dissects the advantages of numerical superiority by providing historical examples, such as the unsuccessful battles of Frederick the Great, whose troops were fewer in number. At the same time, war surpasses material conditions to include psychological factors and other types of uncertainties that affect its course. Such arguments were revolutionary in the author’s time.

“War in its highest aspects consists not of an infinite number of little events, the diversities in which compensate each other, and which, therefore, by a better or worse method are better or worse governed, but of separate great decisive events which must be dealt with separately.”

Method governs action in war, including readiness exercises outside of combat. In this way, method pertains more to the realm of tactics. However, there are limits to using method in war strategy for this very reason: The overall course of war is not a mathematical sum of smaller events defined by the quality of method. Rather, it is the decisive battles that define its course. In other words, this is another example of where reducing war to purely material qualities and ignoring its uncertainties and subjective features is an erroneous approach.

“However preeminently a great Commander does things, there is always something subjective in the way he does them; and if he has a certain manner, a large share of his individuality is contained in it, which does not always accord with the individuality of the person who copies his manner.”

Military genius is one of the key features of war theory for Clausewitz, as discussed in The Role of Military Genius in War theme in more detail. At the same time, military genius demonstrates the limitations of theory because of subjective qualities, probabilities, and human psychology. The limits of theory is an important thematic trajectory throughout this book. For this reason, the author believes that theory must be general enough to account for all probabilities.

“Strategy is the employment of the battle to gain the end of the war; it must therefore give an aim to the whole military action, which must be in accordance with the object of the war; in other words, strategy forms the plan of the war, and to the said aim it links the series of acts which are to lead to the same, that is to say, it makes the plans for the separate campaigns, and regulates the combats to be fought in each.”

Throughout the text, Clausewitz reminds the reader of the differences between tactics and strategy in warfare. Strategy guides the overarching political aims of the war and thus has an effect on combat. However, there are specific aspects of combat that are strictly guided by tactics. The transition of certain tactical questions into the realm of strategy is one of the dialectical aspects of On War. Overall, strategy and tactics have a relationship but remain in separate spheres.

“The higher we rise in a position of command, the more do the mind, understanding, and penetration predominate in activity, the more therefore is boldness, which is a property of the feelings, kept in subjection, and for that reason we find it so rarely in the highest positions, but also then so much the more to be admired.”

Clausewitz separates the mind and feelings into two separate spheres. Such distinctions were not uncommon in his time. He suggests that high-ranking officers typically focus on rational activities of analyzing and planning rather than giving into emotionality. In contrast, courage and boldness are more typically associated with lower-ranking soldiers than the high command. Its rarity among the commanders responsible for large numbers of people is admirable. Overall, this discussion features Clausewitz’s themes of The Role of Human Psychology in War and The Role of Military Genius in War.

“If we cast a glance at military history in general, there we find so much the opposite of an incessant advance towards the aim, that standing still and doing nothing is quite plainly the normal condition of an army in the midst of war, acting, the exception.”

Despite popular belief, Clausewitz suggests, throughout history armies have spent more time being idle rather than being engaged in active combat. This reality makes combat exceptional in war. It also means that idleness adds to the uncertainties and probabilities in war and sets limits to generalizations. At the same time, such pauses are not an absence of war, but rather an integral part of it. Such thinking was novel in the author’s time.

“But modern battles are not so by accident; they are so because the parties find themselves nearly on a level as regards military organisation and the knowledge of the art of war, and because the warlike element inflamed by great national interests has broken through artificial limits and now flows in its natural channel. Under these two conditions, battles will always preserve this character.”

There are strong similarities in warfare in the late-18th and early-19th centuries in Clausewitz’s view. They are the result of the European armies being at roughly the same level in many ways, such as technological development and organization. Such similarities inform the generalizations for writing on war theory, which then helps in combat.

“Destruction of the enemy's military forces is in reality the object of all combats; but other objects may be joined to that, and these other objects may be at the same time predominant; we must therefore draw a distinction between those in which the destruction of the enemy's forces is the principal object, and those in which it is more the means.”

The author argues that the destruction of the enemy’s forces is a key feature of victory. After all, destroying an army’s ability to function means that it cannot rise up again and present a challenge. However, as a means, rather than an end, this destruction is likely linked to overarching political objectives. This thinking ties into Clausewitz’s view of war as a political instrument.

“Let us not hear of generals who conquer without bloodshed. If a bloody slaughter is a horrible sight, then that is a ground for paying more respect to war, but not for making the sword we wear blunter and blunter by degrees from feelings of humanity, until someone steps in with one that is sharp and lops off the arm from our body.”

According to Clausewitz, war is the means to attain a political objective when other means have been exhausted or are unavailable. Violence is an integral part of combat by making the enemy submit to one’s will. It is important to be prepared for war—and even to initiate it—to meet this challenge in an adequate way rather than increase the possibility of losing a war by waiting and submitting to a stronger foreign power. The latter is a subject of discussion in Book IV on the features of defense.

“Only think for a moment, when the organism of a human being is in a disordered and fainting state, what a difference it must make to him whether he falls sick in a house or is seized in the middle of a high road, up to his knees in mud, under torrents of rain, and loaded with a knapsack on his back; even if he is in a camp he can soon be sent to the next village, and will not be entirely without medical assistance, whilst on a march he must be for hours without any assistance, and then be made to drag himself along for miles as a straggler. How many trifling illnesses by that means become serious, how many serious ones become mortal.”

Marches are an integral part of warfare taking place during the pauses between combat. Clausewitz considers them highly damaging to an army through their repetitive wear and tear. Soldiers lack medical attention, illnesses are exacerbated, while the necessity of always being ready for combat remains, causing psychological strain. Such graphic descriptions supplemented by historical examples from Napoleon’s invasion of Russia show the realities of war.

“The power of enduring privations is one of the finest virtues in a soldier, and without it no army is animated with the true military spirit; but such privation must be of a temporary kind, commanded by the force of circumstances, and not the consequence of a wretchedly bad system, or of a parsimonious abstract calculation of the smallest ration that a man can exist upon.”

Throughout the book, the author emphasizes many psychological factors relevant in warfare, including resilience and perseverance. However, dealing with suffering brought on by the lack of food should not be a regular feature if an army is to have normal functioning. Clausewitz provides a historical example of Frederick II’s army when the latter was not the case. Such examples provide a glimpse into the realities of war beyond combat.

“This shows clearly how the subsistence of troops may have a general influence upon the direction and form of military undertakings, and upon the choice of a theatre of war and lines of communication.”

Beyond munitions and shelter, troops require substantial food supplies. Clausewitz demonstrates the way lines of operation have a direct impact on the basic functioning of an army. Alternatively, longer lines or losing access to them lead to devastating results, as was the case with Napoleon’s 1812 retreat from Russia. For this reason, supply routes are also the targets of attacks by the adversary.

“We have said that the dependence on the base increases in intensity and extent with the size of the army, which is easy to understand. An army is like a tree. From the ground out of which it grows it draws its nourishment; if it is small it can easily be transplanted, but this becomes more difficult as it increases in size.”

Clausewitz relies on a simile to compare an army to a tree. This comparison facilitates envisioning the amount of resources a large army requires to sustain it on a daily basis. The author also shows this difficulty empirically by describing the way armies haul supply wagons, field ovens, and individual rations, as well as how they rely on requisitioning food from the local population. Such examples also serve as a useful historical record of the Napoleonic Wars era.

“Without that general striving for rest and the maintenance of the existing condition of things, a number of civilised states could not long live quietly side by side; they must necessarily become fused into one. Therefore, as Europe has existed in its present state for more than a thousand years […] if the protection afforded by the whole has not in every instance proved strong enough to preserve the independence of each individual state, such exceptions are to be regarded as irregularities in the life of the whole, which have not destroyed that life, but have themselves been mastered by it.”

The author displays his understanding of foreign policy and international relations in Europe. He perceives Europe as a continent divided into many states, but, at the same time, featuring a balance of power. Clausewitz argues that it is a certain level of respect for collective security that is the cause of this arrangement. He is also cognizant of the 1648 Peace of Westphalia (195) being responsible for the balance of power in Europe in his lifetime, which further demonstrates his understanding of geopolitics.

“[T]he state of expectation and of action—which last is always a counterstroke, therefore a reaction—are both essential parts of the defensive; for without the first, there would be no defensive, without the second no war. This view led us before to the idea of the defensive being nothing but the stronger form of war, in order the more certainly to conquer the enemy.”

Defense is the longest section in this book because Clausewitz believes it is a stronger form of warfare. At the same time, he uses the dialectic method to address the relationship between defense and an attack because the former develops offensive features when it is successful. The paradox of defense is especially evident here since the author conceptually perceives it as the initiator of war by anticipating an attack.

“A people’s war in civilised Europe is a phenomenon of the nineteenth century. It has its advocates and its opponents: the latter either considering it in a political sense as a revolutionary means, a state of anarchy declared lawful, which is as dangerous as a foreign enemy to social order at home; or on military grounds, conceiving that the result is not commensurate with the expenditure of the nation's strength.”

Clausewitz does not examine civil wars or guerilla warfare but is cognizant of these forms. Here, he discusses the drawbacks of forming a people’s army to support the defensive war effort in a country under attack. These drawbacks feature anarchic elements or those that could be exploited by hostile foreign powers.

“We have seen that the defensive in war generally—therefore, also, the strategic defensive—is no absolute state of expectancy and warding off, therefore no completely passive state, but that it is a relative state, and consequently impregnated more or less with offensive principles. In the same way the offensive is no homogeneous whole, but incessantly mixed up with the defensive.”

The author describes the relationship between an attack and defense in absolute terms. The dialectical method is evident in this discussion as each of the two sides features the elements of the other. Furthermore, the attack and defense contain fewer or more of these opposite elements when they interact with each other.

“Victory, as a rule, springs from a preponderance of the sum of all the physical and moral powers combined; undoubtedly it increases this preponderance, or it would not be sought for and purchased at a great sacrifice.”

Victory in battle, or the entire war, may be the main objective or a means to acquiring an overarching political aim. Attaining victory involves using both material, quantifiable features like numerical superiority, and subjective features like individual and group psychology.

“In order to ascertain the real scale of the means which we must put forth for war, we must think over the political object both on our own side and on the enemy's side; we must consider the power and position of the enemy's state as well as of our own, the character of his government and of his people, and the capacities of both, and all that again on our own side, and the political connections of other states, and the effect which the war will produce on those States.”

In Book VIII, the author examines the way one would plan a war. Whereas it is impossible to account for all the smaller-scale eventualities, such a plan needs to consider the chief features that may affect the course of the war and the attainment of its principal aim. In the warfare of Clausewitz’s time, this planning meant considering not only mathematical factors like the size of an opponent’s army, but also subjective aspects like its national character, the relationship between the opponent’s government and its people, and the allies on each side.

“Plundering and devastating the enemy's country, which play such an important part with Tartars, with ancient nations, and even in the Middle Ages, were no longer in accordance with the spirit of the age. They were justly looked upon as unnecessary barbarity, which might easily be retaliated, and which did more injury to the enemy's subjects than the enemy's government, therefore, produced no effect beyond throwing the nation back many stages in all that relates to peaceful arts and civilisation.”

In the final section of this book, the author briefly traces the development of warfare from ancient times until the early 19th century. In his view, wars eventually moved away from pillaging a territory and devastating its civilians on a mass scale. Instead, wars focused on attaining political goals in a more efficient way. These developments stand in contrast to 20th-century world wars, which returned to targeting civilians on a mass scale such as with the World War II firebombing of Tokyo.