In the case of Western Union Telegraph Company v. Pennsylvania Railroad Company in 1904, the U.S Supreme Court ruled that a contract between two private companies did not violate antitrust laws. The dispute arose when Western Union entered into an agreement with Pennsylvania Railroad to lease telegraph lines for fifty years and agreed to pay a percentage of its gross receipts as rent. Other railroad companies claimed this was unfair competition and violated antitrust laws because it gave Western Union exclusive use of these lines. However, the court held that since both parties were private entities and there was no coercion involved in forming their agreement, it did not constitute restraint on trade or commerce among states under federal law.

In the dissenting opinion for Western Union Telegraph Company v. Pennsylvania Railroad Company, Justice Harlan argued that the majority's decision was inconsistent with previous rulings and principles of equity. He contended that Western Union had not been granted an exclusive right to operate telegraph lines along railroad routes, but rather a privilege subject to reasonable regulation by Congress under its power over interstate commerce. The company's refusal to allow other companies access to these routes constituted an unjust monopoly in violation of federal law and public policy. Furthermore, he disagreed with the majority's interpretation of contracts between Western Union and various railroads as granting absolute control over telegraph operations on their property; instead, he viewed them as merely providing for joint use or operation of such facilities. Thus, according to Justice Harlan’s perspective, Pennsylvania Railroad should have been allowed equal access without interference from Western Union.