Power to interpret the Sherman Act, and thus power to make broad changes to antitrust policy, is currently vested in the Supreme Court. But reevaluation of existing competition rules requires economic evidence, which the Court cannot gather on its own, and technical economic savvy, which it lacks. To compensate for these deficiencies, the Court has turned to amicus briefs to supply the economic information and reasoning behind its recent changes to antitrust policy. This Article argues that such reliance on amicus briefs makes Supreme Court antitrust adjudication analogous to administrative notice-and-comment rulemaking. When the Court pays careful attention to economic evidence and arguments presented in amicus briefs, it moves the process away from a traditional Article III case or controversy and towards rulemaking under the Administrative Procedure Act (APA) where any interested party can influence the decision. In doing so, the Court sacrifices some of the epistemological benefits of Article III’s standing requirements. In the case of antitrust, those costs are probably outweighed by how much the Court benefits from hearing the amici’s economic arguments. But while the Court’s hybrid rulemaking – quasi-administrative and quasi-judicial – may improve upon the traditional judicial model, it cannot realize the full benefits of APA rulemaking. The awkwardness of using amicus curiae briefs like comments on a rulemaking suggests a more dramatic shift in authority over the Sherman Act is necessary. Power to interpret the Act in the first instance should go to an administrative agency
