Counterinsurgency

Counterinsurgency (COIN) is the comprehensive approach used to defeat an armed movement that seeks to overthrow a government through irregular warfare. Unlike conventional combat where the objective is to destroy enemy military forces, COIN focuses on separating the insurgent from the population, winning the loyalty and trust of civilians, and building the capacity of the host nation's government and security forces.

The United States has extensive experience with counterinsurgency, from the Philippines at the turn of the 20th century through Vietnam and most recently in Iraq and Afghanistan. The 2006 Counterinsurgency Field Manual (FM 3-24), co-authored by General David Petraeus, codified the "population-centric" approach that emphasized protecting civilians, providing essential services, and building relationships with local leaders as the keys to defeating an insurgency.

COIN operations are notoriously difficult, expensive, and time-consuming. They require patience, cultural understanding, and political will sustained over years or decades. The mixed results in Iraq and Afghanistan have led to significant debate within the military about the appropriate role of counterinsurgency in U.S. strategy, with many arguing that the focus should return to preparing for conventional great-power competition.