In countries around the world, politicians distribute patronage jobs to supporters in exchange for a wide range of political services - such as helping with campaigns and electoral mobilization. Patronage employees (clients) engage in these political activities that support politicians (patrons) because their fates are tied to the political fate of their patrons. Although conventional wisdom holds that control of patronage significantly increases an incumbent's chance of staying in power, we actually know very little about how patronage works. Drawing on in-depth interviews, survey data, and survey experiments in Argentina, Virginia Oliveros details the specific mechanisms that explain the effect of patronage on political competition. This fascinating study is the first to provide a systematic analysis of the political activities of mid and low-level public employees in Latin America. It provides a novel explanation of the enforcement of patronage contracts that has wider implications for understanding the functioning of clientelist exchanges.