The United States Supreme Court case, United States v. Reading Company (1925), involved the federal government's antitrust action against several railroad companies including the Reading Company. The government accused these companies of monopolizing commerce in violation of the Sherman Antitrust Act by controlling coal mines and fixing prices for anthracite coal. The railroads argued that they were not engaged in interstate commerce when mining and selling coal, thus their actions did not violate antitrust laws. However, the Supreme Court disagreed with this argument stating that while mining is a local activity, selling and transporting mined products across state lines constitutes interstate commerce which falls under federal jurisdiction. Therefore, any attempt to control or manipulate such activities could be considered as an infringement on competition law. In its ruling favoring the U.S., it held that even though individual steps may be intrastate in character when separated from others; if they form part of a larger scheme to restrain trade among states then they fall within Congress' regulatory power over interstate commerce.

In the dissenting opinion for United States v. Reading Company, Justice McReynolds disagreed with the majority's interpretation of anti-trust laws and their application to this case. He argued that these laws were not intended to regulate competition but rather prevent monopolies and conspiracies in restraint of trade. In his view, the Reading Company did not violate any law by acquiring a controlling interest in two competing coal companies because it was merely an investment made without intent to restrain trade or create a monopoly. Furthermore, he believed that such acquisitions should only be considered illegal if there is clear evidence showing they significantly restrict competition or control prices across an entire market sector - conditions which were not met in this case according to him.