Thesis (Ph.D.) - Indiana University, Political Science, 2013For a non-state terrorist group, internal communication and coordination are necessary to maintain organizational control and implement the group's strategy; but this need for interpersonal contact also makes the group vulnerable to disruption by government authorities. How then might these competing demands shape a group's organizational structure? This dissertation will examine how the presence or absence of a safe haven can interact with a group's choice of organizational structure to determine its ability to survive, conduct attacks, and mobilize supporters. Furthermore, it will look at whether and how groups change their organizational structures to adapt to their political environments. To this end, process tracing, the congruence procedure type 2, and cross-case comparison will applied to the cases of four Western, Cold War-era groups (The Provisional Irish Republican Army, The Red Army Faction, The Red Brigades and The Weather Underground) to both identify the critical factors that impact group organizational structure and to explain how these factors exert their influence.