Whether the operation of the per se rule in criminal antitrust cases violates the constitutional prohibition against instructing juries that certain facts presumptively establish an element of a crime

QUESTION PRESENTED The Sherman Act, 15 U.S.C. § 1, creates civil and criminal liability for certain anticompetitive conduct. Specifically, it prohibits any contract or combination “in restraint of trade or commerce.” Consistent with the common law, this Court has long interpreted this language to require proof of an “unreasonable” anticompetitive effect. Most antitrust cases are therefore governed by the “rule of reason” and require an explicit finding of unreasonableness. At the same time, this Court has held that certain business arrangements are unlawful per se. In those cases, proof of one of those specified arrangements operates as a conclusive, or irrebuttable, presumption that the arrangement is unreasonable. The question presented is whether the operation of the per se rule in criminal antitrust cases violates the constitutional in the Fifth and Sixth Amendments—against instructing juries that certain facts presumptively establish an element of a crime.