This essays will define the notion of center of gravity and the relationship between a center of gravity and vulnerabilities. It also will explain the distinction between the strategic and operational level of center of gravity, and discuss the purpose of the concept.
Army Field Manual 100-5 relies on Clausewitz's definition of center of gravity, stating that it "is the hub of all power and movement upon which everything depends." This definition appears in Chapter Six, which also defines the three levels of war, strategic, operational and tactical; however, the FM does not treat the subject in depth nor distinguish adequately between strategic versus operational centers of gravity.
Clausewitz's discussion of the issue suggests that at the operational level the center of gravity is "always found where the mass is concentrated most densely." He believed that at the operational level a commander must understand the dynamics of space, mass, and time. Space was the theater of operations, mass was the army and time was the campaign. Enemy vulnerabilities or decisive points were not to be confused with center of gravity. These are operational and tactical targets the conquest of which gives the CINC a clear advantage over his enemy. Such targets may consist of flank attacks, attacks on isolated units, or attacks against key terrain, transportation hubs, logistical bases, air fields, staging areas, command and communication centers, lines of communication and other targets, the defeat of which will enable one side to gain or maintain the initiative. Both SOF and conventional forces can be used by the CINC to strike these vulnerable points.
This "finding" of the enemy and the "fixing" of his capability to move freely and mass his own forces are the preludes to the ultimate objective of getting at the enemy center of gravity in one massive final blow. Any attack against a target that does not further the stated objective of destroying the enemy center of gravity is therefore a waste of time and resources (Hitler's air war against England and the US's failure to confront the real threat in Vietnam are examples).
The CINC and his planners normally have considerable latitude when it comes to defining the operational center of gravity of the enemy force within the theater boundaries and how to employ the center of gravity of his own forces to bring about the favorable "collision" or "duel" referred to by Clausewitz in On War. It is at the strategic level where the concept often becomes confused. Clausewitz conceded that other strategic centers of gravity exist, citing capital cities in countries suffering domestic strife (typical of many smaller third world countries with unstable governments) and situations in which a small country is protected by a larger one where a choice is made to defeat the army of the protector instead of directing a campaign directly against the small nation. Modern theorists have expanded the concept to include: industrial areas in countries where industry is concentrated, cannot be dispersed and is central to the war effort (areas of Germany during WW II); poor public morale or lack of "national will" to continue the war effort (Vietnam war is often cited); and, political elites, where a country is under the "iron fist" of a despot or the charismatic leadership of a popular figure (US attack on Yamamoto, attempts against Castro, and the raid on Qadhafi's residence and headquarters are examples). The national command authority (NCA) through the JCS should identify a conceptual strategic center of gravity that can be articulated as part of a statement of grand and national military strategy to support and guide the efforts of the CINC within the theater and area of operation. Obviously, if the theater is limited in size and the strategy well focused at the NCA level, the strategic and operational centers of gravity may blend together.
It is important to avoid a couple of pitfalls associated with the center of gravity concept. A massed attacking force can overextend its lines of communication and reach a "culminating point" of success. The German attack on Russia is often cited as an example. Also, it is conceivable that the swift and violent defeat of an enemy can actually come too soon in the conflict. The enemy simply gives up substantial forces and capitulates with the intent to commence a new conflict after a period of reconstitution of his force (critics cite the Gulf War as an example).