Current United States counterinsurgency (COIN) doctrine espoused in Army Field Manual (FM) 3-24 Counterinsurgency is inadequate for the realities of the complex security environment that exist in the world today. This paper starts with a literary review of the current counterinsurgency doctrine proposed in FM 3-24 and subsequently discusses relevant critiques of that doctrine. Next, a case study on Afghanistan is then used as a vehicle to show where the current doctrine is failing in this contemporary environment which focuses on developing an appreciation of the cultures of the counterinsurgent, the insurgent and the host nation. Recommendations are then offered to revise FM 3-24 so that it can adjust to meet the needs of commanders on the ground in Afghanistan and other COIN challenges that are likely to dominate modern warfare for the next several decades. To validate these proposed changes to FM 3-24, they are superimposed on the deteriorating situation in Somalia. A revised FM 3-24 needs to provide that doctrinal starting point so military leaders can meet the contemporary challenges the U.S. faces in defeating the expanding global jihad.