The common law of slavery, like all of the common law, was a bridge connecting past to future. The bridge arose from the Anglo- American practice of following precedent: Once a case was decided, judges typically had to decide similar cases in the same way. To construct slave law, judges drew upon prior cases concerning free persons, animals, and other property. The outcome was a set of economically efficient rules that served as structural support for the Southern way of life.

In most contexts, efficiency means something good. Here, it was sinister: Efficient law preserved the market value of slaves and thus helped slavery flourish. But protecting property rights in slaves had other, unintended, consequences. In cases of personal injury, for example, antebellum courts tended to shield slaves more than free people. As a result, those who argued vigorously after the Civil War on behalf of ordinary consumers, workers, and victims of accidents or assaults sometimes turned to slave-law precedents for guidance. The practice of stare decisis thus meant that slave law not only built upon earlier traditions but also paved the way for later law. In fact, slave cases did serve as precedents in many types of postbellum suits. In other conflicts, the connections to slave law were less direct, either because statutory rules supplanted the common law or because older cases tend to be cited less frequently.