Cries for revolution fill the air. The structuralism for which anti-monopolists pine, however, would bring antitrust to a regrettable place. For all its flaws, the competitive effects era has striven for accuracy. Modern analysis hones in on the causal determinants of unilateral static effects – diversion ratios and margins – and contextualizes them in light of the fluidity and dynamism of the market at issue. It does not stop there. Customers’ expectations about the merger or practice weigh heavily on the analysis. Probable efficiency gains, anticipated seller responses, and customers’ ability to discipline attempted exercises of market power complete the picture. That canvas bestows the richest possible basis for inferring the presence or absence of tractable harm. Neo-Brandeisians would abandon that exercise in favor of something rigid and imprecise. In their preferred world, market shares and concentration ratios would not guide the analysis, but dispose of it.