Acosta, L. (2025). Fabricating Communists: The Imagined Third That Reinvented the National Fault Line in Mid-Twentieth-Century Colombia’s Civil War. American Sociological Review, 90(6), 947-984. https://doi.org/10.1177/00031224251371066 (Original work published 2025)

Contrary to the classical sociological view that social conflict reinforces preexisting political divisions, this article argues that civil war can reinvent them. I examine this phenomenon through the evolution of civil wars in Colombia in the mid-twentieth century, a period initially marked by a Liberal–Conservative conflict that developed into a civil war between the state and communist guerrillas. Drawing on archival records, oral histories of civilians and combatants, and newspapers, I demonstrate that when one party invents an “imagined third”—an actor, external to the original conflict dyad, who lacks any connection to an actual military or political threat—to blame for the violence in civil war, a self-fulfilling logic turns the imagined third into a tangible enemy of the nation, thereby creating a new fault line. In Colombia, politicians’ baseless accusations and preemptive actions against Communists activated three mechanisms of fault line formation—enemy legitimation, boundary demarcation, and identity shift—that materialized the very revolutionary threats they claimed to prevent. This analytic framework of fault line formation in civil war opens new avenues for examining how political discourse can become self-fulfilling, how international threats are transformed into local enemies, and how wartime actors’ opportunities for action evolve—including the conditions necessary for sustained peace.