The Path of Law: Legal Uncertainty and Issues of First Impression in the U.S. Courts of Appeals

When deciding new issues, judges face uncertainty about how cases map into their existing understanding of the law. This uncertainty can lead to conflicting decisions on the same legal question, generating inconsistent law. I develop a formal theory of judicial decision making, where courts learn about and rule on new legal issues. I find that courts learn most from their ideological allies; however, increasing the ideological distance between courts can either increase or decrease legal uniformity. Using an original dataset of cases of first impression in the U.S. Courts of Appeals, I find that increasing the ideological distance between two courts increases the probability of disagreement if the previous court’s decision is in-line with their relative bias, and decreases disagreement when the decision runs counter to their relative bias. My findings highlight the ways that courts can use decisions from even ideologically distant peers to learn about new legal issues.