Divided Not Conquered
Authors: Perkoski Evan 
Published: August 2022

Abstract
Less academic: Terrorist, rebel, and insurgent groups face myriad challenges. Between state repression and fears of infiltration and defeat, it is no surprise they are prone to infighting, instability, and division. And these divisions are meaningful: one led the Islamic State to break from Al Qaeda, and others have perpetually plagued the Irish Republican Army, Palestinian militants, and many more. This book analyzes how armed groups fracture and how splinter groups behave. It is the first to look inside these organizations and to understand the specific disagreements leading fractures to occur. It shows how disagreements are commonly driven by disputes over ideology, leadership, and strategy. Drawing on research from organizational studies to social psychology, and by leveraging analogies from business firms to religious sects, the book shows how these disputes uniquely shape the behavior and survivability of breakaway splinters. When motivated by single, shared disagreement, splinters tend to exhibit higher cohesion, clearer objectives, and greater survivability. And when motivated by strategy in particular, splinters typically attract the most hardline operatives and subsequently adopt increasingly lethal tactics and strategies. The book tests these claims comprehensively. Statistical analyses reveal a clear link between internal disagreements and splinter behavior across countries and over time. Case studies of republican militants in Northern Ireland, Basque militants in Spain, and the Islamic State in Syria and Iraq then confirm these trends. As a result, this book demystifies a complex albeit common event with ramifications for counterinsurgency, counterterrorism, and understanding increasingly fragmented conflicts around the globe. More academic: Armed groups are tenuous organizations. They face difficult environments and uncertain challenges that make instability, division, and organizational fractures common. But when fractures occur, what explains how breakaway groups behave? Drawing on social and group dynamics that afflict everything from political parties to religious sects, this book shows how a splinter group’s trajectory is not predetermined, but is in fact shaped by its motivations for breaking away. Splinters emerging from a single, shared internal disagreement form with clear organizational objectives that attract a highly cohesive base of recruits. This lowers the odds of defection and infiltration, making it easier to decentralize operations and ultimately survive. Armed groups also break apart for a variety of reasons. Ideological, strategic, and leadership disputes each uniquely shape the goals and membership composition of breakaway groups. Strategic disagreements create the most radical splinters since they usually attract dissatisfied hardliners away from the parent. These claims are tested using a mixed-methods research design. Statistical analyses of a new data set reveal strong support for the theory across countries and over time, while in-depth case studies of republican militants in Northern Ireland, Basque militants in Spain, and the Islamic State in Syria and Iraq confirm the theory’s more specific implications. As a result, this book refocuses attention away from external dynamics, like state repression and conciliation, and towards internal dynamics that can better explain how armed groups fragment, operate, and survive.