In the landmark case of The Standard Oil Company of New Jersey v. The United States, 1910, the U.S Supreme Court ruled that Standard Oil had violated the Sherman Antitrust Act by engaging in monopolistic practices and ordered its dissolution into 34 independent companies. This decision was based on a new interpretation of the "rule of reason" doctrine which stated that only combinations and contracts unreasonably restraining trade were subject to federal antitrust law. In this context, it was determined that Standard Oil's vast control over oil production and distribution constituted an unreasonable restraint on trade as it suppressed competition and manipulated prices. This ruling significantly expanded government regulation over corporations while also paving way for future antitrust legislation aimed at curbing corporate power.

In the dissenting opinion for The Standard Oil Company of New Jersey v. The United States, Justice Harlan disagreed with the majority's interpretation of the Sherman Antitrust Act. He argued that any contract or combination which directly restrains interstate commerce is illegal under this act, regardless of whether it was reasonable or not. In his view, allowing a 'rule of reason' to determine legality would undermine Congress's clear intent in passing this legislation - to prevent monopolies and protect competition. Furthermore, he believed that such an approach would give courts too much discretion in deciding what constitutes a restraint on trade and could lead to inconsistent rulings. Thus, he dissented from the ruling which found Standard Oil guilty but only because its actions were deemed unreasonable restraints on trade.