titutional boundaries. In the process, this framework offers the first systematic basis for understanding how the precise nature of each type of access should guide the actions of antitrust courts. A. The Origins of the Essential Facilities Doctrine The principal provision of the antitrust laws governing unilateral action taken by firms is Section 2 of the Sherman Act, which provides that "[e]very person who shall monopolize, or attempt to monopolize, or combine or conspire with any other per- son or persons, to monopolize any part of the trade or commerce among the several States, or with foreign nations, shall be deemed guilty of a felony" (15 U.S.C. § 2). The use of the active verb, "monopolize," is generally interpreted as criminalizing not the mere possession of monopoly power, but rather the anticompetitive conduct Networks in Telecommunications create and sustain monopolies. 4 Thus, courts have generally concluded that Section 2 was not meant to reach monopolies obtained through natural features of the market or through competition on the merits. In the words of Learned Hand's landmark decision in United States V. Aluminum Co. of America (Alcoa): A market may, for example, be SO limited that it is impossible to produce at all and meet the cost of production except by a plant large enough to supply the whole demand. Or there may be changes in taste or in cost which drive out all but one purveyor. A single producer may be the survivor out of a group of active competitors, merely by virtue of his superior skill, foresight and industry. (148 F.2d at 430).5 Proposals to criminalize "no fault" monopolization have appeared from time to time, based on the grounds that the mere existence of a monopoly increases price and reduces quantity regardless of whether it arises innocently or through anti- competitive acts. 6 Courts, however, have declined to condemn the mere possession of monopoly power out of concern that doing SO would deter firms from engaging in the competition on the merits (through product innovation 