What is a center of gravity? What's the difference between strategic and operational CoG?

LTC Jason Mackay and SGT David Thomas, thank you both for your answers, hearing it differently from what's written in the JP helped a lot.

As LTC Jason Mackay stated, it is essentially the one thing you can capture, kill, or destroy that will cause the enemy to give up resistance. The problem is that the actual CoG (regardless of level) is rarely known. In most cases, commanders have to make an informed guess at what the CoG is. Sometimes they are right, sometimes not. This concept is one of Clausewitz's more difficult ones to grasp due to the subjectivity inherent in it. If you look at different wars or even different battles in the same war, the CoG is almost always different. It is good to analyze and see if you can identify the CoG. Then you can focus your efforts there.

MSG (Join to see) Center of Gravity comes from Clausewitz, which in the original German was der schwerpunkt, meaning the hub of all things. On War is the basis of most US doctrine.

The concept of the center of gravity is that if you eliminate the center of gravity, that will cause the enemy to fall apart. In Desert Storm, I believe they identified the center of gravity at the operational level was the Republican Guard. An instructor once used this test to determine if something was a CoG: close your eyes, if this thing went away, would the enemy effort fall apart?

Part of this is to ensure you are committing resources properly. Your campaign must either be a series of physical objectives to eliminate the CoG and win the fight or a series of logical lines of operations that defeats or controls the CoG (the population could be the CoG in an insurgency).

There is another joint process called critical capabilities and critical vulnerabilities where you lay them out and figure out ways to negate their critical capabilities to fight you, preferably by exploiting critical vulnerabilities so you don't run your forces into a buzz saw. In Desert Storm, a critical vulnerability was their integrated air defense system, most of it depending on Prime power and a series of radar sites. So at H hour, we used Army CCA to take out theses sites, which threw the door open for the Air Force to pummel the rest of the system and strike targets to get after the CoG.

A center of gravity at the operational level and one at the strategic level may be the same. They might not be. A Corps Commander is an operational level commander, so what would the Corps Commander of III Corps identify as a CoG in a Campaign as opposed to the what the CENTCOM Commander at the strategic level identify as a CoG for the theater level. An operational CoG may be a specific unit or capability, while strategically the CoG may be the ability to keep their forces in the field fighting against you or a specific region for sustainment or reinforcement. You have to picture a world where there is more than one Corps fighting in the same operation.