Numerous commentators have characterized the Roberts Court’s antitrust decisions as radical departures that betray a pro-business, anticonsumer bias. That characterization is inaccurate. Although some of the decisions do represent significant changes from past practice, the “pro-business/anti-consumer” characterization fails to appreciate the fundamental limits of antitrust, a body of law that requires judges and juries to make fine distinctions between procompetitive and anticompetitive behaviors that frequently resemble each other. Although false acquittals of anticompetitive conduct may harm consumers, so may false convictions of procompetitive actions. And efforts to eliminate errors in liability judgments are themselves costly. Optimal antitrust rules will aim to minimize the sum of decision costs (the costs of reaching a liability decision) and expected error costs (the social losses from false convictions and false acquittals). Each of the Roberts Court’s antitrust decisions can be defended in light of this “decision-theoretic” approach, an approach calculated to maximize the effectiveness of the antitrust enterprise, to the ultimate benefit of consumers. This Article first describes the fundamental limits of antitrust and the decision-theoretic approach such limits inspire. The Article then analyzes the Roberts Court’s antitrust decisions, explaining how each coheres with the decision-theoretic model. Finally, the Article predicts how the Court will address three issues likely to come before it in the future: tying, loyalty rebates, and bundled discounts.