In the United States v. Terminal Railroad Association of St. Louis case in 1911, the Supreme Court ruled that a group of railroad companies violated antitrust laws by creating a monopoly over rail traffic in St. Louis, Missouri. The Terminal Railroad Association was formed by several major railway companies who collectively bought all the local railway bridges and ferries to control access across the Mississippi River at St.Louis - effectively controlling all rail transportation into and out of city. This created an unfair advantage for these railways against their competitors as they could dictate terms for use of these facilities or deny access altogether. The government argued this arrangement breached Sherman Antitrust Act which prohibits business activities that reduce competition in marketplace.The court agreed with government's argument stating it was indeed an unreasonable restraint on trade and ordered association to allow equal access to its facilities on fair terms under supervision from Interstate Commerce Commission.This ruling established important precedent regarding monopolies' power over essential public utilities like transport infrastructure.

In the dissenting opinion for United States v. Terminal Railroad Association of St. Louis, it was argued that the majority's decision to uphold a lower court ruling against the railroad association constituted an overreach of federal power and interference in private business affairs. The dissenters believed that while there may have been some anti-competitive practices by the association, these did not necessarily equate to a violation of antitrust laws as interpreted by the majority. They contended that this case involved local commerce within Missouri state lines rather than interstate commerce which would fall under federal jurisdiction according to their interpretation of Commerce Clause jurisprudence at this time period. Therefore, they felt it should be left up to individual states or other regulatory bodies with more direct oversight powers instead of being decided on by Supreme Court justices who might lack specific expertise in railway operations or economic matters related to such industries.