The case of People's Tobacco Company, Limited v. American Tobacco Company in 1917 revolved around the issue of trademark infringement and unfair competition. The People's Tobacco Company (PTC) accused the American Tobacco Company (ATC) of intentionally imitating their cigarette packaging to confuse consumers and steal business. PTC had been using a specific design for its 'Ostrich' brand cigarettes which ATC allegedly copied for its own 'Mimic' brand cigarettes. The Supreme Court ruled in favor of PTC, stating that while there was no direct evidence proving ATC’s intention to deceive customers, the similarities between both packages were too significant to be coincidental or accidental. This led them to conclude that ATC did indeed infringe upon PTC’s trademark rights with an intent to mislead consumers into buying their product instead, thereby engaging in unfair competition.

In the dissenting opinion for People's Tobacco Company, Limited v. American Tobacco Company, it was argued that the majority had misinterpreted and wrongly applied the Sherman Act. The dissenting justices believed that there was no evidence of an attempt to monopolize trade or commerce among states by either party involved in this case. They contended that a mere increase in business size does not necessarily constitute an illegal restraint on trade or monopoly under the law as interpreted by previous court rulings. Furthermore, they disagreed with how lower courts handled certain evidentiary matters during trial proceedings and felt these errors were significant enough to warrant reversal of judgment against American Tobacco Company.