The ways that judges and lawyers make and justify their arguments and decisions have profound impacts on our lives. Understanding those practices in light of theories of reasoning and argumentation is thus critical for understanding law and the society it shapes. An inquiry that explores the very foundations of all legal reasoning leads to a broad, important question: How do lawyers and judges use cited cases in their legal arguments? It turns out there is practically no empirical research to suggest the answer. As the first step in a comprehensive empirical effort to answer this question, this article performs a ground-breaking analysis of a carefully constructed corpus of judicial opinions and the advocates’ briefs that gave rise to them. It tells us not just that these textual artifacts cited court opinions, but how they used the opinions in their reasoning. The article then reveals whether judges and advocates placed different values on different ways of using cited cases. These legal authors used them to make assertions about legal rules in their arguments about twice as often as they used them as legal analogies and about four times as often as they used them to make policy arguments. Perhaps unsurprisingly, the practices of judges differed significantly from those of advocates. But so, too, did those of the prevailing advocates and their less fortunate opponents. On functional grounds, therefore, this article empirically supports the claim that there is a hierarchy of rational legal argumentative appeals, and that there is a common look to the ‘losing brief.’ This special convergence between theory and function can transform ongoing debates across legal scholarship on the value of drawing on precedent as a tool for rational persuasion.