Whether a business association that publishes a rule for its members can immunize the rule, and members' adherence to it, from being considered a conspiracy subject to Sherman Act Section 1 by making the rule optional —as held by the Ninth Circuit below and the Tenth Circuit —or whether an association's rule can be a conspiracy even if optional —as held by the First, Third, and Fifth Circuits and supported by the Department of Justice and this Court's precedent.

Whether a business association that publishes an optional rule for its members can immunize the rule from being considered a conspiracy under Sherman Act Section 1