The Northern Pacific Railway Co. v. United States case in 1957 was a landmark decision by the U.S Supreme Court that dealt with antitrust laws and their application to railroad companies. The government accused Northern Pacific Railway of violating the Sherman Antitrust Act, arguing that certain clauses in its land grant deeds constituted illegal restraints on trade as they required purchasers of its land to exclusively use its rail services for transportation needs. The railway company contended these were lawful property rights protected under the Constitution's Fourteenth Amendment, not commercial arrangements subject to antitrust law scrutiny. However, the Supreme Court ruled against them unanimously (9-0), stating that such restrictions indeed violated federal anti-monopoly laws because they suppressed competition and controlled prices unfairly within interstate commerce - regardless if it involved real estate transactions or not.

In the dissenting opinion for Northern Pacific Railway Co. et al. v. United States, Justice Harlan argued that the majority's decision was too broad and could potentially disrupt legitimate business practices in addition to curbing anti-competitive behavior. He contended that not all tying arrangements should be considered per se violations of antitrust laws as they can sometimes enhance competition rather than restrict it. Furthermore, he expressed concern over the potential impact on property rights, arguing that a landowner should have some discretion over how their property is used or sold without automatically violating antitrust laws if conditions are attached to its use or sale.