Medary.com

A while back, I downloaded the Counterinsurgency Manual . . . the one that was written by the incoming U.S. General in Iraq, David Petraeus.

Does any of this sound familiar?

One common feature of insurgencies is that the government that is being targeted generally takes awhile to recognize that an insurgency is occuring.  Insurgents take advantage of that time to build strength and gather support.  Thus, counterinsurgents often have to "come from behind" when fighting an insurgency.  Another common feature is that forces conducting COIN operations usually begin poorly.  Western militaries too often neglect the study of insurgency.  They falsely believe that armies trained to win conventional wars are automatically prepared to win small, unconventional ones.  In fact, some capabilities required for conventional success--for example, the ability to execute operational maneuver and employ massive firepower--may be of limited utility or even counterproductive in COIN operations.  Nonetheless, conventional forces beginning COIN operations often try to use these capabilities to defeat insurgents;  they almost always fail.

The military forces that successfully defeat insurgencies are usually those able to overcome their institutional inclination to wage conventional war against insurgents.  They learn how to practice COIN and apply that knowledge.

Emphasis mine.