I develop a formal model of Supreme Court opinion-writing in an environment of uncertainty. In particular, the model captures how the Supreme Court will optimally design the specificity of its legal rules. The model focuses on the tradeoff between more precise rules which are controlling in a smaller subset of cases against less precise rules, which have wider applicability but yield less certain outcomes. When the basic model is considered in a dynamic world in which the Court is able to hear multiple cases, it yields insights about how the factual representativeness of a case and the clarity of existing precedent jointly affect its optimal opinion-writing and willingness to hear new cases. These last implications provide theoretical foundations for theoretical and empirical questions about rule-making, case selection, and the construction of doctrine.