In the case of Walker Process Equipment, Inc. v. Food Machinery & Chemical Corp., 1965, the U.S Supreme Court ruled that a patent holder who enforces a fraudulently obtained patent could be held liable under antitrust laws for monopolistic practices. The court found that if a company obtains or maintains its monopoly in any part of commerce through fraudulent means such as perjury during the patent application process, it can be sued by competitors for damages under Section 2 of Sherman Act which prohibits monopolies and attempts to monopolize trade or commerce among states or with foreign nations. This ruling established an important precedent linking intellectual property law with antitrust law.

In the dissenting opinion for Walker Process Equipment, Inc. v. Food Machinery & Chemical Corp., Justice Harlan disagreed with the majority's view that antitrust laws could be applied to patent law cases where fraud was alleged on the U.S Patent Office. He argued that this interpretation of antitrust laws would lead to an increase in litigation and potentially discourage inventors from seeking patents due to fear of potential legal consequences if their application contained any errors or omissions, even unintentional ones. Furthermore, he expressed concern about lower courts' ability to handle such complex issues involving both patent and antitrust law without clear guidance from Congress or a specialized agency like the Federal Trade Commission (FTC). In his view, it would have been more appropriate for these matters to be handled by administrative agencies with expertise in both areas rather than generalist judges who might not fully understand all nuances involved.