The United States v. Felt & Tarrant Manufacturing Company case in 1930 revolved around a dispute over the classification of imported goods for tariff purposes. The Felt & Tarrant Manufacturing Company, known for producing comptometers (early mechanical calculators), had imported certain parts from abroad to be used in their manufacturing process. However, disagreement arose regarding how these imports should be classified under the Tariff Act of 1922 and consequently what duty rate they were subject to. The U.S government argued that these items should fall under "parts of machines" which attracted a higher duty rate while the company contended that they were merely "finished articles". The Supreme Court ruled in favor of Felt & Tarrant, stating that since the parts could not function independently as machines but only when assembled into a complete unit, they did not constitute 'parts' within meaning of tariff law and thus would attract lower duties.

The dissenting opinion in the United States v. Felt & Tarrant Manufacturing Company case argued that the majority's decision was inconsistent with previous rulings regarding patent law and taxation. The dissent contended that a tax on patented articles, such as those produced by Felt & Tarrant, should not be considered an excise tax but rather a direct tax on property rights granted by patents. This interpretation would mean that such taxes are unconstitutional unless apportioned among states according to population, as required for all direct taxes under Article I of the Constitution. The dissent further criticized the majority for failing to adequately distinguish this case from prior cases where similar taxes were struck down as unconstitutional direct taxes.