 Ass'n, 224 U.S. 383 (1912), is the first case in which the United States Supreme Court held it a violation of the antitrust laws to refuse to a competitor access to a facility necessary for entering or remaining in the market (an "essential facility").In this case a combination of firms carried out the restrictive practice, rather than a single firm.That made the conduct susceptible to challenge under section 1 of the Sherman Act (15 U.S.C.