e companies, called incumbent LECs, to provide access to all of their network elements on an unbundled Werden (1987); Areeda and Hovenkamp (2008c). Ex parte United States, 226 U.S. 420, 421 (1913); Terminal R.R. Ass'n V. United States, 236 U.S. 194, 195-96 (1915); Terminal R.R. Ass'n V. United States, 266 U.S. 17, 27 (1924); see also Lipsky and Sidak (1999), discussing continuing judicial involvement and repeated interpretation of the original decree. Areeda and Hovenkamp (2008c). 86 Over the course of the litigation, the company originally named NYNEX first merged with Bell Atlantic and then merged with GTE to form a new corporation called Verizon. We will follow the Supreme Court's convention by referring to all of these entities as Verizon (540 U.S. at 402 n. 1). Antitrust as Applied to Network Industries basis. The specific source of concern was the computer system that Verizon used to process requests for service, known as its OSS. Verizon's competitors complained that Verizon was not fulfilling the orders that they placed through the OSS in a timely manner. Parallel investigations by both federal and state regulatory authori- ties led both agencies to adopt orders providing some relief. A customer of one of Verizon's competitors filed an antitrust suit arguing that the same conduct violated Section 2. The Supreme Court rejected the customer's claims in an opinion that accepted many of the criticisms of the essential facilities doctrine discussed above. In SO doing, the opinion touched off a lively debate about the proper scope of Section 2 liability and in particular about the future of the essential facilities doctrine. 1. The Economics of Vertical Exclusion The Supreme Court's discussion of the substantive antitrust claim began by noting that the antitrust laws do not penalize the mere possession of monopoly power absent proof of exclusionary conduct. Indeed: The mere possession of monopoly power, and the concomitant charging of monopoly prices, is not only not unlawful; it is an important element of the 