Political scientists working on clientelism have become interested in the relationships between brokers and the politicians and parties for whom they work. In most of this research, brokers are seen as inherently disloyal and normally act against the interests of their patrons, unless monitoring efforts are enacted. In contrast, we argue that territorial brokers have strong incentives to construct long-term, dependent relationships with their patrons, which diminishes the likelihood of cheating, while their patrons also wish to maintain durable ties with brokers to hold an assured voter base. We argue that politicians prefer brokers who have a good reputation for providing their voters with goods and assuring their votes. Still, sometimes brokers go rogue and cheat on their bosses. This study, which is based on more than fifty in-depth interviews with both local politicians and brokers in Mexico City, examines the conditions under which brokers remain loyal and those that promote cheating. We identify two factors that explain this variation—electoral competitiveness and the level of resource autonomy between brokers and politicians. Non-autonomous brokers working under conditions of low competition tend to have high probabilities of remaining loyal, while independent brokers working under high competitiveness will often resort to cheating.