There is a vast and rapidly expanding literature on democratic backsliding and the impact of populist politics on liberal democratic institutions. Yet surprisingly little of this work examines public bureaucracy and the impact of backsliding on its role in governing. This book suggests that the public bureaucracy has been one of the targets of democratic backsliding driven by populist politics and argues that, in the face of such attacks, the bureaucracy must act as a guardian of the constitution and of liberal democratic norms. This is not a call for bureaucratic dominance in government, but a recognition that liberal democracy requires checks on the powers of majoritarian governments. In this light, the bureaucracy can be understood as a fourth branch of government, capable of enforcing those checks. While addressing urgent contemporary challenges, this book is grounded in historical and philosophical reflections on bureaucracy and its legitimate role in governing.