Desertion, or the unauthorized exit from an armed group, has major implications for counterinsurgency, war termination, and recruitment dynamics. While existing research stresses the importance of individual motivations for desertion, organizational decline, in the form of military and financial adversity, can also condition desertion. Organizational decline undermines a group's instruments to channel individual preferences into collective action. These instruments include selective incentives, ideological appeal, and coercion. When the binding power of these instruments diminishes, individual desires start to dominate behavior, making desertion more likely. The Revolutionary Armed Forces of Colombia (FARC) insurgency is used to examine this argument with a multimethod approach. First, a quantitative analysis employs unique data on more than 19,000 reported FARC deserters from 2002 to 2017, provided by the Colombian Ministry of Defense. Guarding against threats to causal inference, statistical analysis indicates that organizational decline drives desertion. Second, a qualitative analysis uses a large body of detailed reports on interviews with deserters conducted by Colombian military personnel. The reports demonstrate that organizational decline weakens selective incentives, group ideology, and a credible coercive regime, and fosters desertion through these mechanisms. These findings provide key insights for policymakers, given that desertion can both contribute to ending conflict and accelerate the recruitment of new combatants.
