In the case of Kennecott Copper Corp. v. United States (1964), the Supreme Court ruled in favor of the U.S government, upholding a decision by the Federal Power Commission (FPC). The FPC had ordered Kennecott Copper Corporation to refund excess charges it had collected for electricity sold to Nevada power companies from its steam-electric plant in McGill, Nevada. The court found that Kennecott was subject to regulation under Part II of the Federal Power Act because it was engaged in selling electric energy for resale and transmission in interstate commerce. This ruling confirmed that federal agencies have jurisdiction over private corporations when they engage with public utilities or services affecting interstate commerce.

In the dissenting opinion for the case of Kennecott Copper Corp. v. United States, Justice Harlan disagreed with the majority's interpretation of Section 7 of the Clayton Act. He argued that this section should not be applied to prevent a merger simply because it may potentially lessen competition in an area where there is no existing competition between two companies involved in a merger or acquisition transaction. In his view, such an application would extend beyond what Congress intended when drafting and passing this legislation. Furthermore, he contended that applying Section 7 in this manner could have far-reaching implications on business transactions and economic growth as it might deter mergers and acquisitions even when they are beneficial to both businesses involved and do not harm any competitors or consumers.