In the 1943 case of Allen Calculators, Inc. v. National Cash Register Co., et al., Allen Calculators accused National Cash Register (NCR) and other defendants of violating antitrust laws by conspiring to monopolize trade and commerce in cash registers and accounting machines. The Supreme Court ruled that NCR did not violate any antitrust laws because they had a valid patent on their products, which gave them exclusive rights to manufacture, use, or sell those items for a certain period of time. Furthermore, the court found no evidence supporting Allen's claim that NCR conspired with others to restrain trade or create a monopoly in violation of the Sherman Act. Therefore, it was held that having a patent does not automatically constitute an illegal restraint on trade unless there is clear proof showing intent or actions taken towards creating such restrictions.

The dissenting opinion in the case of Allen Calculators, Inc. v. National Cash Register Co., et al., argued that the majority's decision to uphold a lower court ruling against Allen Calculators was incorrect. The dissent believed that there were genuine issues of material fact regarding whether National Cash Register had engaged in unfair competition and monopolistic practices, which should have been decided by a jury rather than summarily dismissed by the judge at trial. They contended that evidence presented suggested possible predatory pricing and market manipulation tactics used by National Cash Register to maintain its dominant position within the industry, potentially violating antitrust laws. Therefore, they felt it was inappropriate for these matters to be resolved without full consideration through a trial process.