In the case of Toyota v. United States in 1924, the Supreme Court ruled on a dispute over import duties. The issue arose when Toyota imported automobile chassis from Japan and attached them to bodies manufactured in the US. The company argued that these should be classified as "parts" for tariff purposes, which would result in lower import duties than if they were considered complete automobiles. However, U.S Customs disagreed with this classification and imposed higher tariffs applicable to finished vehicles. The Supreme Court sided with U.S Customs' decision stating that even though the cars were not fully assembled upon arrival into America, their essential character was still identifiable as motor vehicles intended for transportation use rather than mere parts or accessories thereof. This ruling established an important precedent regarding how goods are classified for customs purposes - focusing more on their ultimate purpose or function rather than their state at time of entry into country.

In the dissenting opinion for Toyota v. United States, Justice McReynolds argued that the majority's interpretation of the Tariff Act was incorrect. He believed that it did not apply to parts of automobiles imported separately but intended for assembly in America as complete cars. According to him, this misinterpretation led to an unjust double taxation on these items - once when they were imported and again when assembled into a car. He also pointed out inconsistencies in how different types of auto parts were taxed under this ruling, which he felt further demonstrated its flawed logic and unfairness. Furthermore, he criticized the majority's reliance on Congress' supposed intent behind passing such laws without providing any solid evidence supporting their claims about what lawmakers had actually intended at that time.