This introduction outlines the core puzzle of “insincere coercion” in international relations: why do states frequently issue ultimatums they expect, or even intend, to be rejected? Conventional wisdom holds that coercion is difficult and often fails, yet this book argues that it is frequently an instrumental step toward broader foreign policy goals. The chapter introduces the concept of insincere coercion, distinguishing it from bluffing or domestic diversion. It outlines two variations, expected and intentional failure, where coercion is deliberately utilized despite the unlikelihood of a negotiated settlement. Four primary rationales for this behavior are identified: mobilizing international and/or domestic support, making an example of a target, restoring deterrence, and moving the goalposts by increasing demands. To support these claims, the author introduces the Coercion in Interstate Militarized Conflict (CIMC) dataset, which demonstrates that while coercion alone succeeds less than half the time, coercers ultimately achieve their foreign policy objectives in 59 percent of cases when utilizing violence. By reframing coercion failure not as a diplomatic miscalculation but as a designed, strategic choice, the introduction sets the stage for a comprehensive reevaluation of how the threat and use of military force function in modern statecraft.