Much has been said and written regarding the legal and economic merits of U.S. v. Microsoft and the practicality of antitrust in high technology industries. The focus here is what this prominent case says about the role of economics in general, and in particular, ?post-Chicago? approaches. Is antitrust economics and law on a progressive path, producing more refined analyses of industrial practices? Or is the path more like that of a pendulum, with doctrines coming back in style that had once fallen out of fashion?

U.S. v. Microsoft suggests that the path of antitrust may be cyclical rather than progressive. The crux of the argument is that in U.S. v. Microsoft, the three aspects of an economically sound antitrust case?theory, evidence, and remedy?were largely independent of, if not inconsistent with, each other. Roughly speaking, the theory focused on monopolizing application platforms, the evidence spoke to monopolizing browser distribution, and the remedy treated applications themselves as the competitive lynchpin. The plaintiffs? success at trial suggests, in contrast to the older aphorism that ?hard cases make bad law,? that this ?easy case? may be responsible for ?bad law,? where an ?easy case? is one where the victory at trial was so compelling and ?bad law? refers to an ultimately reduced role for economics as an antitrust policy guidepost.

These observations need not imply that Microsoft?s conduct was benign. Isolating the theory, evidence, and remedy from the case, one can construct three potential rationales for finding Microsoft?s actions anticompetitive. We also identify three additional stories based on tying with transaction costs, reputation-preserving predatory pricing, and intellectual property. That none of these stories were told suggests that U.S. v. Microsoft signals a return to pre-Chicago antitrust. Those preferring a less constraining role for economics in antitrust courts may agree with this assessment without finding it disagreeable. Moreover, there may be no better alternative?legislation or regulation need not lead to better outcomes. It may offer small comfort to observe that antitrust is not the only policy area in which progress in economic theory may ironically lead to regress in its importance.