In the United States v. Bertelsen & Petersen Engineering Co., 1938, the Supreme Court dealt with a case involving an alleged violation of antitrust laws by two engineering companies. The government accused these firms of conspiring to restrain trade and monopolize interstate commerce in connection with bids for public works projects in several states. However, the court ruled that there was insufficient evidence to prove such conspiracy or monopoly existed between them. It found no clear proof that they had agreed not to compete against each other on certain contracts or that their actions significantly affected interstate commerce as required under antitrust law provisions. Therefore, it dismissed the charges against both companies.

The dissenting opinion in the case of United States v. Bertelsen & Petersen Engineering Co., 1938, argued that the majority's decision to uphold a lower court ruling against Bertelsen & Petersen was incorrect. The dissenting justices believed that there was insufficient evidence to prove that the company had violated antitrust laws by engaging in price-fixing and monopolistic practices. They also disagreed with the majority's interpretation of these laws, arguing they were meant to prevent harmful business practices rather than punish companies for their success or size. Furthermore, they contended that this ruling could have negative implications for other businesses and potentially stifle competition and innovation within various industries.