This dissertation consists of three essays examining the development of aggressive and violent political attitudes and actions. The first paper examines the relationship between genetic variation, volumetric changes in the ventral diencephalon, and aggressive attitudes towards outgroup members. Results from a mediation analysis demonstrate the role of brain development in the formation of hostile political attitudes. The second paper uses a formal model to explore the matching of potentially politically violent persons with organizations engaged in ongoing armed conflict. The final paper presents and tests a biological model of political violence. Results from a Candidate Gene Analysis demonstrate the inciting role of political repression in persons with proclivities towards aggression and violence.