The Maricopa Foundation for Medical Care was a nonprofit organization established by the Maricopa County Medical Society to promote fee-for-service medicine. Roughly 70 percent of the physicians in Maricopa County belonged to the foundation. The foundation's trustees set maximum fees that members could charge for medical services provided to policyholders of approved medical insurance plans. To obtain the foundation's approval, insurers had to agree to pay the fees of member physicians up to the prescribed maximum. Member physicians were free to charge less than the prescribed maximum, but had to agree not to seek additional payments in excess of the maximum from insured patients. The Arizona attorney general filed suit for injunctive relief against the Maricopa County Medical Society and the foundation, arguing that the fee agreement constituted per se illegal horizontal price-fixing. The district court denied the state's motion for a partial summary judgment. The Ninth Circuit Court of Appeals affirmed on the ground that the per se rule was not applicable to the case. Was the Ninth Circuit correct?