In the 1903 U.S. Supreme Court case Fargo v. Hart, the court examined whether a state could tax an interstate commerce company for business conducted within its borders. The plaintiff was Wells Fargo & Company, which operated as both an express and freight business across multiple states including California where it had its principal place of business but also in Iowa where it maintained offices and depots. The defendant was Charles G. Hart, Treasurer of Polk County in Iowa who imposed taxes on Wells Fargo's operations there. The main issue revolved around whether this taxation violated the Commerce Clause of the Constitution that prohibits states from interfering with interstate commerce without Congressional approval. The Supreme Court ruled in favor of Wells Fargo stating that while a state can impose reasonable regulations on businesses operating within their jurisdiction to ensure public safety or health, they cannot use these powers to directly tax out-of-state entities for engaging in interstate commerce activities unless approved by Congress. This decision affirmed that only Congress has power over regulating interstate trade thus preventing individual states from imposing burdensome taxes or restrictions on companies engaged in such trade.

In the dissenting opinion for Fargo v. Hart, it was argued that the majority's decision to uphold a tax on gross receipts of express companies operating in multiple states violated principles of interstate commerce. The dissent contended that this taxation constituted an undue burden on interstate commerce and thus should be considered unconstitutional under the Commerce Clause of the U.S. Constitution. They believed that such taxes could potentially lead to double taxation or discriminatory practices against certain businesses by different states, which would disrupt free trade among states and undermine national economic unity. Furthermore, they disagreed with the majority's interpretation of previous court decisions related to similar issues, arguing those cases did not establish a precedent for upholding such taxes but rather cautioned against them due to their potential negative impact on interstate commerce.