Section 5 of the Federal Trade Commission Act makes unfair methods of competition illegal and gives the FTC authority to enforce this proscription. The term unfair method of competition is undefined by the statute – indeed, Congress deliberately left the term ambiguous in order that judicial construction of the term would not prevent the FTC from restraining such conduct. Ordinarily, one would expect that courts would defer to agency interpretations of such inherently and deliberately ambiguous terms – this is a very clear case for Chevron deference. Remarkably, however, the FTC has relied exclusively upon judicial construction of the term (viz., that proscription of unfair methods of competition allows the FTC to enforce antitrust la...