We live in a golden age of comparative constitutional law. Liberal democratic ideas have diffused readily around the world, and certain features such as judicial review and constitutional rights are now nearly universal. At the same time, recent years have seen a pronounced trend toward the erosion of democracy. This book argues that the rhetorical triumph of liberal democratic constitutionalism, and the tendency toward democratic retrenchment, are fully consistent phenomena. Legal globalization has a dark side: norms intended to protect and promote liberal democratic constitutionalism can often readily be used to undermine it. Abusive constitutional borrowing involves the appropriation of liberal democratic constitutional designs, concepts, and doctrines to advance authoritarian projects. Some of the most important hallmarks of liberal democratic constitutionalism—including constitutional rights, judicial review, and constituent power—can be turned into powerful instruments to demolish rather than defend democracy. The book offers a wealth of examples, selected both to shed new light on well-known cases such as Hungary, Poland, and Venezuela, as well as to expand discussions by considering contexts such as Cambodia, Rwanda, and Fiji. It also discusses the implications of the phenomenon of abusive constitutional borrowing for those who study and promote liberal democracy and related fields like human rights. It suggests ways in which the construction of norms might be improved to protect against abuse (what we call ‘abuse-proofing’), as well as ways in which monitoring regimes might be more attuned to the threat. Finally, it suggests recasting debates about liberal democracy to emphasize contestation, rather than mimicry.