The history of criminal justice in the U.S. is often described as a pendulum, swinging back and forth between strict punishment and lenient rehabilitation. While this view is common wisdom, it is wrong. In Breaking the Pendulum, Philip Goodman, Joshua Page, and Michelle Phelps systematically debunk the pendulum perspective, showing that it distorts how and why criminal justice changes. The pendulum model blinds us to the blending of penal orientations, policies, and practices, as well as the struggle between actors that shapes laws, institutions, and how we think about crime, punishment, and related issues. Through a re-analysis of more than two hundred years of penal history, starting with the rise of penitentiaries in the 19th Century and ending with ongoing efforts to roll back mass incarceration, the authors offer an alternative approach to conceptualizing penal development. Their agonistic perspective posits that struggle is the motor force of criminal justice history. Punishment expands, contracts, and morphs because of contestation between real people in real contexts, not a mechanical "swing" of the pendulum. This alternative framework is far more accurate and empowering than metaphors that ignore or downplay the importance of struggle in shaping criminal justice. This clearly written, engaging book is an invaluable resource for teachers, students, and scholars seeking to understand the past, present, and future of American criminal justice. By demonstrating the central role of struggle in generating major transformations, Breaking the Pendulum encourages combatants to keep fighting to change the system.