May a Section 1 claim be dismissed pursuant to Fed. R. Civ. P. 12(b)(6), consistent with Twombly, based on evidence suggesting an alternative, non-conspiratorial reason for the challenged conduct, where the complaint also contains substantial factual allegations disputing that alternative inference?

Question Presented, upon which the circuits are divided, is: May a Section 1 claim be dismissed pursuant to Fed. R. Civ. P. 12(b)(6), consistent with Twombly, based on evidence suggesting an alternative, non-conspiratorial reason for the challenged conduct, where the complaint also contains substantial factual allegations disputing that alternative inference? Second, Section 2 of the Sherman Act prohibits the monopolization (or attempted monopolization) of any trade or commerce through anticompetitive conduct. Such anticompetitive conduct is “conduct which unnecessarily excludes or handicaps competitors,” thereby “impairing competition.” Aspen Skiing v. Aspen Highlands Skiing Corp., 472 U.S. 585, 597 (1985). The Second Question Presented is: To adequately allege anticompetitive conduct for purposes of a Section 2 claim involving a threatened refusal to deal, must plaintiffs allege a “substantial foreclosure” of competition?