The United States v. Arnold, Schwinn & Co., et al. case in 1966 was a landmark decision by the Supreme Court that significantly impacted antitrust laws and business practices within the U.S. The court ruled against bicycle manufacturer Arnold, Schwinn & Co., who had established exclusive territories for its distributors and prohibited them from selling bikes outside of their assigned areas. This practice was deemed to be a violation of Section 1 of the Sherman Antitrust Act as it restrained trade and limited competition among retailers. Furthermore, Schwinn's policy of only allowing franchised retailers to sell certain models also violated this act because it restricted consumer choice without any justifiable business reason or benefit to consumers.

In the dissenting opinion for United States v. Arnold, Schwinn & Co., Justice Fortas argued that the majority's decision to categorize Schwinn's distribution practices as per se violations of antitrust laws was an overreach. He contended that these practices should be evaluated on a case-by-case basis rather than being automatically deemed illegal. According to him, such blanket condemnation could potentially stifle legitimate business strategies and innovations in distribution methods which are not inherently anti-competitive or harmful to consumers. Furthermore, he expressed concern about the potential negative impact this ruling might have on small businesses who rely heavily on exclusive dealing arrangements for their survival against larger competitors.