This book presents a systematic reassessment of the theoretical and empirical foundations of the democratic peace literature. Three distinct theoretical models of how domestic political institutions shape the foreign policy choices of state leaders are developed and Huth and Allee then test hypotheses from each model against an original data set of 348 territorial disputes from 1919-95. Each territorial dispute is divided into three separate but related phases for empirical analysis: Challenge the Status Quo Stage, Negotiation Stage and Military Escalation Stage. Their statistical results provide strong support for the importance of democratic accountability and norms in shaping decisions to negotiate and settle disputes as well as to threaten force and escalate to war. The findings of this book address central debates and provide many insights into understanding when and why democratic leaders engage in cooperative or confrontational foreign policies.