 944 (1991). 31 Nat'l Cable & Telecomm. Ass'n V. Brand X Internet Servs., 545 U.S. 967, 1001-02 (2005); U.S. Telecom Ass'n V. FCC, 290 F.3d 415, 428-29 (D.C. Cir. 2002). U.S. Department of Justice (1984, 4.213). The 1992 statement that accompanied the issuance of the new Horizontal Merger Guidelines indicated that Section 4 of the 1984 Guidelines continued to provide the relevant guidance for nonhorizontal mergers (U.S. Department of Justice 1992). The Clinton Administration considered revising the Non-horizontal Merger Guidelines but chose not to do SO (Yoo 2002). Jefferson Parish, 466 U.S. at 12-16; Kodak, 504 U.S. at 462, 464, 481. 34 506 U.S. 447, 459 (1993); see also Brooke Group Ltd. V. Brown & Williamson Tobacco Corp., 509 U.S. 209, 224-25 (1993) ("Earlier this Term, we held in the Sherman Act § 2 context that the plaintiff [must] prove 'a dangerous probability that [the defendant] would monopolize a particular market," quoting Spectrum Sports, 506 U.S. at 459). Antitrust as Applied to Network Industries related market a structural precondition of the essential facilities doctrine (Alaska Airlines, 948 F.2d at 546-47), whereas the U.S. Department of Justice's 1984 Merger Guidelines (§$ 4.211-4.212) require that the secondary market be concentrated and protected by entry barriers. Furthermore, in at least one case, four justices of the Court explicitly recognized the one-monopoly-rent theorem, as have some lower courts implementing the essential facilities doctrine. 35 The presence of regulation can also affect incentives to integrate vertically. Reg- ulators may explicitly encourage or discourage vertical integration into particular lines of business. The effect of regulation on incentives is illustrated by the classic example sometimes called the "Bell Doctrine" or "Baxter's Law" because of the role it played in the breakup of AT&T during Stanford law professor William Baxter's tenure as head of the Antitrust Division (Baxter 1983). It relies upon the fact that an input producer cannot extract all of the 