In the case of American Sugar Refining Company v. United States in 1900, the Supreme Court upheld a lower court's decision that the American Sugar Refining Company had violated the Sherman Antitrust Act by acquiring control over several other sugar refining companies and thereby creating a monopoly. The company argued that it was not engaged in interstate commerce because its activities were confined to manufacturing within individual states. However, this argument was rejected by both courts on grounds that while manufacturing is indeed local activity, when it becomes part of an overarching scheme to monopolize trade among states, it falls under federal jurisdiction as per the Commerce Clause of Constitution. Thus, even though each act taken individually might be legal and intrastate in nature; collectively they formed an illegal restraint on trade at national level which Congress could regulate.

The dissenting opinion in the American Sugar Refining Company v. United States case argued that the Sherman Act was not intended to prevent monopolies, but rather to preserve competition and protect consumers from unfair business practices. The justices believed that the majority's interpretation of the law was too broad and could potentially criminalize legitimate business activities. They also disagreed with the idea that a company could be considered a monopoly simply because it controlled a large share of an industry or market, arguing instead that only companies which used their power to harm competitors or manipulate prices should be targeted by antitrust laws. Furthermore, they contended that there were other legal mechanisms available for dealing with monopolistic behavior without resorting to such drastic measures as breaking up successful businesses.