On Tactics, page 17
Clausewitz on the Center of Gravity
The center of gravity concept as presented by Clausewitz can be separated into a few distinct elements. First, we must parse the tactical idea from the strategic. Clausewitz begins his discussion of the concept with a tactical conception of the idea. This first conception deals with the sphere of influence of a successful battle being related to “the size of the defeated force.”8 The bigger the victory the bigger the effect. Even the Prussian himself remarked on the banality of this idea. After a brief explanation of the center of gravity in physics, however, Clausewitz departs from the banal and begins to flesh out this kernel into a strategic idea.
From this point on Clausewitz departs from the purely physical conception of the center of gravity. He says that centers of gravity “will be found wherever the forces are most concentrated” but does not say that those concentrated forces are the center of gravity. He ascribes to the center of gravity the source of cohesion and a certain unity. A concentration of military power is the result of a center of gravity, and is not the center of gravity itself. An actor on the strategic defense will concentrate military force at points that are valuable to it, like a particularly valuable province, for example. Likewise, the actor on the strategic offense will concentrate military force to seize that province. That concentration is an indicator of a center of gravity but is not necessarily the center of gravity itself.
Further explication is found in the examples Clausewitz uses. He does use a belligerent’s army as an example of a center of gravity, but he also lists many more. He says that cohesion is “frequently found only in mutual political interests” and that the center of gravity could be a belligerent’s capital city, an ally with a large army, the shared interests of an alliance, and “personalities of the leaders and public opinion.”9 He did not limit the concept to a military force as does the U.S. military.
Finally, in his Book VIII, chapter 9, he states, “The task of reducing the sources of enemy strength to a single center of gravity will depend on: 1. The distribution of the enemy’s political power” and “The situation in the theater of war where the various armies are operating.”10 Again, the political nature of the center of gravity is evident and connected solely with a strategic actor’s political power and its relation to the strategic situation.
What all of these examples have in common is the political aspect. The unity and cohesion of a belligerent arises from, and is intimately connected with, the political aim of the war. This is obvious when Clausewitz describes the political interest of an alliance as the sole source of its cohesion; even when he describes armies as centers of gravity, though, the armies he lists are closely linked with politics. His three examples of armies are those of Alexander the Great, Gustavus Adolphus, and Frederick the Great. All these are sovereigns who commanded in the field, not just great generals. Even Napoleon Bonaparte, another of Clausewitz’s named examples, was himself a concentration of both military and political power. Since a center of gravity is that which gives a military force its cohesion and unity and sets it in opposition against another, a strategic center of gravity could be much more than just the examples set forth by Clausewitz. The cohesion of a military force could be the product not just of a sovereign leader or the need to defend a capital, but also the result of religion or ideology or even—in the case of mercenary armies—the result of money. Clausewitz mentions such possibilities very early in On War, in his Book I, chapter 2: “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 to paralyze it, that gain us new allies, favorably affect the political scene, etc.” (emphasis in original).11 Such actions that have “direct political repercussions” as he emphasized, are those that affect the center of gravity.
Current Thinking on the Center of Gravity
The debate surrounding the center of gravity revolves around what a center of gravity actually is. Most theorists seem to be searching for a standard, trying to decide whether it is a military force, a geographical location, a relevant population, or a military leader. What is consistent in all of the ideas that follow is the center of gravity’s connection with politics.
Antulio Echevarria is clear on the matter that the center of gravity is not the army itself. He states, “First, the center of gravity concept only applies where a certain ‘unity’ (Einheit) and ‘connectivity’ or ‘interdependence’ (Zusammenhang) exist between the enemy’s forces and the space they occupy.”12 This implies that the center of gravity is not the army or even the space that it occupies: it is the reason that an army is cohesive as a fighting unit in the field and the reason it is where it is. This can only be the existence of that army as a servant of a political force and the aim of that political force when it comes to the ground it occupies. An army is not formed and then stationed on a country’s border in and of its own accord. It is formed to serve that country and that country’s border is defined by a political entity. The center of gravity then is connected to the political aim that brought that army to that piece of land.
Hew Strachan’s view of the center of gravity brings us a little closer to the concept. According to Strachan, “What now preoccupied him [Clausewitz] was the relationship between the theatre of war and the armies operating within it. Consistent with his rejection of Bülow, he was not prepared to see geography itself as possessing a centre of gravity: key points in the terrain gained their significance not in themselves but from the troops which occupied them, and thus the ‘real key to an enemy’s country is usually his army.’”13 This is still not satisfying, however, as Clausewitz’s center of gravity draws forces to it. If the forces themselves create the center of gravity, what is drawing them to the point? Again, our only answer can be the political goal. Take, for example, the British and French effort to seize control of the Suez Canal from Egypt in 1955. The canal did not become a center of gravity in the conflict because of the forces sent there nor the fact that it was a canal. It became a center of gravity once Egypt asserted its political control in a way unsatisfying to England and France. The canal then drew forces to itself because the political aim of all the strategic belligerents was control of the canal. The end of the crisis came when the center of gravity was struck in an unexpected way: President Eisenhower decided to back Egypt’s claim, thus making the political goal of England and France a far more expensive prospect than they had believed. The political aim of each belligerent imbued the Suez Canal with status as a center of gravity during the crisis.
Jon Sumida also identifies the political goal as the key ingredient in the center of gravity. Sumida noticed that, when discussing guerilla warfare, Clausewitz identified the center of gravity as “the personalities of the leaders and public opinion” as noted above.14 According to Sumida, “Here Clausewitz makes it clear that the center of gravity of a defender waging guerilla war is political rather than military, and as such insusceptible to destruction by concentrated military force alone.”15 But is this any different for the conventional army of a defender? If the political aim of the defender is not resistance, there is no reason for the conventional army to resist. As unlikely a scenario as this is, there is still an example. On 15 March 1939 Hitler’s Germany invaded what remained of the already dismembered Czechoslovakia. Rather than resist the invasion, the Czech government capitulated immediately—albeit under duress. The presence of the Czech conventional army was not in and of itself enough of a center of gravity to produce resistance; in fact, a resistance needed to be predicated on the political aim of the Czech government to maintain independence—or at least to fight for it.
Sumida also sees this connection between political aim and the center of gravity: “Clausewitz made clear in Book VI that decisions are not deferred because of physical military factors but because the attacker lacks the will to act. The attacker’s lack of will, in turn, is the product of political considerations.”16 In the case of Czechoslovakia, it was the defender that lacked the political will to create a center of gravity.
In The Strategy Bridge Colin S. Gray lays out strategic effect as a key concept in strategy. Since Clausewitz believes that the most effective blows are those aimed at the center of gravity, it follows that the best way to produce strategic effect is to direct tactical efforts toward it. Gray states, “Battle is truly decisive beyond the narrowest of military confines only when it is the enabling agent for strategic decision.”17 For battle to become that enabling agent of strategic effect, it must be aimed at a strategically vital point, the center of gravity. Thus the center of gravity can act as a forcing function to coordinate the efforts of various tactical actors because (1) it is where tactical blows can produce strategic effect and (2) the political aim of the opponent determines the center of gravity. The center of gravity then assists the strategist in deciding where along the river the strategy bridge should be placed—that point on the enemy shore where, once reached, the most strategic effect on the enemy can be produced.
Sir Lawrence Freedman provides another view of the same dynamic in Strategy: A History: “This [achieving victory] required tracing back the ‘ultimate substance’ of enemy strength to its source and then directing the attack against this source. The target might not be a concentration of physical strength but possibly the point where enemy forces connected and were given direction. Any disruption would maximize effects beyond the immediate point to the larger whole.” Freedman uses Clausewitz’s example of an alliance to explore this dynamic and, like Gray, implies that it is the “unity of political purpose” that is the center of gravity of alliance.18 Thus we see again that political aim and the center of gravity are connected. Indeed, even when a strategic belligerent is not an alliance, it is the political aim that infuses military forces with purpose and will. An army, removed from its purpose of serving a political master of one kind or another, will not offer any coordinated resistance to an opponent thus imbued. During the Arab conquest of the Sassanid Empire in the seventh century AD, Sassanid armies made separate peace arrangements with the Arab invaders once the king, Yazdegerd III, had fled the capital.19 Their political purpose—defense of their king—was removed with the king himself and thus they lost their connection with the state.
Peter Paret, in his essay on Clausewitz in Makers of Modern Strategy, states the idea in stark terms: “The political purpose for which a war is fought should determine the means that are employed and the kind and degree of effort required. The political purpose should also determine the military objective” (emphasis mine).20 We are even closer to a conclusion. Since the political purpose determines military objectives and military objectives will determine concentration of military forces, it follows that the nature of the political purpose will also determine the nature of the center of gravity.
These modern ideas on the center of gravity echo U.S. Navy admiral J. C. Wylie’s criticism of Clausewitz. Wylie believed that a Clausewitzian viewpoint was solely focused on the destruction of the enemy army. He used two examples where a nation was defeated while a majority of the army remained in existence: the Pacific War in 1945 where Japan had significant ground forces remaining in Manchuria, and the Battle of Dien Bien Phu in 1954 that precipitated the defeat of the French even though only a portion of its army was defeated.21 A third example is the 1968 Tet Offensive during the U.S. involvement in Vietnam. The NVA achieved no tactical objectives, caused very few U.S. casualties, and suffered massive casualties of its own. The Viet Cong were almost wiped out. Yet the offensive was a strategic success because the very fact that the communists could mount such an effort clashed with the American government’s rosy narrative of success in the country. The Tet Offensive was a success because it struck at the political goals of the United States through a center of gravity: the American populations’ perceptions of success or failure and their trust in the leadership of President Lyndon B. Johnson.
Finally, the pithy Sun Tzu implies that a center of gravity is something beyond the tactical and physical. He states, “When I wish to give battle, my enemy, even though protected by high walls and deep moats, cannot help but engage me, for I attack a position he must succor.”22 Even if the enemy in this example enjoys great tactical advantages, his opponent gains some measure of control over him by attacking a strategic center of gravity—his base of political support perhaps—thus forcing him to abandon his plan and follow one designed by his opponent.
To summarize all of these ideas, it is clear that the center of gravity of each opponent is interdependent with the political aim of each opponent. An opponent’s center of gravity is underpinned by the will of the opponent to achieve it (or deny it to the opponent); thus striking the center of gravity is the surest means to deplete or shatter the enemy’s will. Identifying it and exploiting it, such as in Sun Tzu’s vignette, can grant one side an advantage: the initiative or even strategic leverage. Thus it is not physical or tactical, although tactical action and physical aspects of war can be imbued with strategic effect by the potential harm done to the opponent’s aims. To return to the example of the Suez Canal crisis, the will of the British and French was shattered by President Eisenhower’s political decision not to support their cause. This was a very direct strike on the center of gravity.
Physics vs. Astrophysics
If so many experts agree on the nature of the center of gravity as a component of the political aims of the opponents and its nonphysical nature, then why is there still so much confusion about the concept? This is a continuing and unfortunate effect of the term’s origin in physics and the limitations of the science of Clausewitz’s day. Because the Prussian had only a limited grasp of physics, due to the training and limitations of science in the early nineteenth century, he did not have the tools to fully flesh out the analogy. Today, however, we do have the tools. The first step is to remove the concept from basic physics and instead examine it through the lens of astrophysics.
Clausewitz’s Physics
It is thought that Clausewitz drew much of his thinking on physics from the lectures of German physicist Paul Erman, who taught at both the University of Berlin and the Prussian war college.23 As director of the war college, Clausewitz and Erman were colleagues. Still, Clausewitz was limited to the physics of his time. We still look at the center of gravity through a lens of elementary physics. In his article for the Naval War College Review, Antulio Echevarria applied these physics to the concept to argue that it is not a source of strength but rather of weakness.24 He uses examples such as boomerangs, marbles, sticks, and the human body. All of these examples do have centers of gravity, but they cannot serve as effective examples when they are always subject to a far more powerful one—that of the Earth’s gravity. The scale of these examples is too small to adequately flesh out the concept. It makes more sense when the examples are as large as planets. Or stars.
Astrophysics
The center of gravity analogy makes more sense when evaluated on a large scale where every object is regular enough in shape so that the center of gravity actually is at the center but the objects move independently. The only way to do that is to look at the physics on a galactic level. The scale of a solar system allows us to demonstrate how mass and gravity interact in the absence of extraneous forces such as the friction of atmosphere.
In a solar system it is the object with the greatest mass that gives the system as a whole cohesion and unity and—through light—animates it as a system. A star, having far greater mass than planets and other objects, holds each of those nearby objects in an orbit. Centrifugal force, however, offsets the gravitational pull of the star, allowing the planets, satellites, or moons a measure of freedom (i.e., not falling into the star) while still chaining the object in place. Additionally, each planet has its own gravitational force so that some objects, like moons, orbit planets and not the star. Moreover, there are many types of stars and other objects, such as black holes, with centers of gravity that exert force on other objects.
Since war is a dynamic interaction between two or more combatants, each with its own center of gravity, we must take the analogy farther and imagine the collision of two solar systems. In this catastrophic event, one would displace the other (which would then most likely be subsumed). If one solar system’s planet hits the planet of another, knocking it out of orbit, this would certainly damage the solar system. But if one solar system is “hit in the star,” the impact would affect the entire solar system. The displacement of one star would pull all of its planets along with it.
This intergalactic billiard ball game would not occur in reality: the gravity from the colliding stars would either fling each star away from each other or the two stars would join together. But it can help us illuminate the concept of the center of gravity.
The star’s center of gravity gives the solar system unity and cohesion by holding each orbiting object in place while allowing those objects (through centrifugal force) a measure of freedom. A center of gravity in war provides the same function. Take Clausewitz’s favorite example, Napoleon Bonaparte. As emperor, Napoleon gave postrevolutionary France cohesion and unity. He decided on the political aims for which all of France strove while under his reign. He held his corps commanders in orbit, but allowed them freedom within his designs. The divisions under a general’s command are analogous to moons or other satellites. Napoleon, however, also controlled other aspects of French power: the navy, economic measures, and diplomatic means. These disparate means were, again, given cohesion by the emperor himself.
