iers actually distribute their custom may overstate Highlands's incremental contribution. From this perspective, the dispute between Highlands and Ski Co. may have been nothing more than a disagreement over what the proper baseline was for dividing the benefits created by their joint venture. This is precisely the type of dispute in which antitrust courts should avoid becoming entangled (Areeda and Hovenkamp 2008c). Last, Ski Co.'s history of selling multiarea tickets both in Aspen and at its other resorts greatly facilitated the remedy in Aspen Skiing. The Court could use these parallel transactions as a basis for fashioning a remedy without having to establish the terms and conditions for such a multiarea ticket out of whole cloth. In cases in which such external benchmarks do not exist, courts will doubtlessly find fashioning appropriate remedies in duty-to-deal cases to be much more difficult. These criticisms, and the decisions' failure to rely upon the essential facilities doctrine, have not stopped lower courts from invoking Otter Tail and Aspen Skiing when requiring monopolists to provide competitors with access to their facilities. What remains controversial is the precise scope of the duty to deal mandated by these cases. B. A Critique of the Essential Facilities Doctrine Even supporters of the essential facilities doctrine recognize that it "has long been a controversial subject under U.S. antitrust law" (Pitofsky et al. 2002, p. 443). 16 Essential facilities claims assert that a firm is using its control of a monopoly input 16 Byars V. Bluff City News Co., 609 F.2d 843, 846 (6th Cir. 1980), similarly calls the essential facilities doctrine "one of the most unsettled and vexatious in the antitrust field." Antitrust as Applied to Network Industries to restrain competition in a vertically related market, either by charging companies requesting access to that resource excessive prices or by denying those companies access to the resource altogether. Rather than selling the input into the open market and al