In the 1947 case International Salt Co., Inc. v. United States, the Supreme Court upheld a lower court's ruling that International Salt Company had violated antitrust laws by engaging in tying arrangements. The company leased salt-processing machines to customers on condition they only use its salt products, which was found to be an unreasonable restraint of trade and commerce under Section 1 of the Sherman Act and Section 3 of the Clayton Act. The Court rejected arguments from International Salt that their actions didn't substantially affect competition or create monopoly power because other companies could still sell similar machines or salts separately. It held such practices inherently anti-competitive regardless of their actual effect on competition due to potential foreclosure effects in tied product markets.

In the dissenting opinion for International Salt Co., Inc. v. United States, it was argued that the majority's decision to find International Salt guilty of violating antitrust laws was based on an overly broad interpretation of those laws. The dissenting justices believed that there wasn't sufficient evidence to prove that the company's leasing agreements significantly hindered competition or created a monopoly in violation of Sections 1 and 2 of the Sherman Act. They contended that just because a business practice might potentially restrict trade doesn't necessarily mean it does so illegally or unreasonably, and thus should not be automatically deemed as anti-competitive behavior without concrete proof showing its adverse impact on market competition.