Drawing on extensive archival work and interviews, Abbey Steele's book offers an engaging account of the history and evolution of the Colombian civil war and develops a compelling theory of the variation in civilian displacement within it. She begins with two puzzles: What explains the timing of the onset of mass displacement in Colombia, which began several years after the onset of the civil war? And why, within locations where residents were racially, ethnically, and socio-economically very similar, did armed groups target certain neighborhoods for displacement but leave others virtually unharmed? Steele argues that armed groups intentionally target violence against civilian supporters of their political rivals to achieve 'political cleansing', or to expel disloyal civilians from contested territories and consolidate territorial control. Local election results can facilitate political cleansing in the context of non-ethnic, irregular civil wars by revealing local-level information about civilian preferences, enabling armed groups to identify – and target for expulsion – the territorial bases of support for rival-aligned parties and candidates. To test these arguments, Steele examines the history of the formation of the FARC-founded party Union Patriótica (UP) and UP’s eventual participation in local-level electoral contests. She finds that collective targeting and political cleansing did not become a feature of the conflict until the UP entered local elections and paramilitaries were able to identify UP supporters. Archival material, evidence from interviews, and municipality-level data show that residents of areas that supported the insurgent-aligned UP were more likely to be displaced compared to other locations, and that paramilitaries targeted them intentionally and systematically. This impressive contribution convincingly and disturbingly shows how elections introduced to engender peace can be turned into tools of war.