Insurgency-the use of protracted low intensity violence and political warfare against a government-has been one of the most pervasive and strategically signifi cant forms of asymmetric confl ict for the past century. In some instances, it actually has succeeded in overthrowing regimes or forcing occupying powers to withdraw from a state, thus redrawing the strategic landscape and altering the course of history. Few other forms of asymmetric confl ict can make this claim. Just as HIV is a particularly dangerous pathology because it integrates with other diseases, insurgency tends to meld with other forms of confl ict, be they terrorism, ethnic struggles, separatism, class struggle, ideological confl ict, narcotraffi cking, or other forms of organized crime. This makes it both a complex and a particularly dangerous opponent, always challenging to the strategist who must deal with it. The United States is once again challenged by insurgencies, this time connected to the Global War on Terrorism.