In the United States v. Ewing case of 1901, the Supreme Court ruled on a matter concerning customs duties and importation laws. The defendant, Ewing, had imported iron ore into Pennsylvania from Cuba and declared it as ballast (weight to stabilize ships), which is not subject to duty fees under U.S law. However, upon inspection by custom officials, they determined that the iron was in fact cargo and therefore subject to taxation. Ewing contested this decision arguing that he intended to use the iron for his own personal use rather than selling it commercially; thus making it exempt from duty charges according to him. The court disagreed with Ewing's argument stating that intent does not change what an item is classified as under customs law - if an item can be sold commercially then it should be considered cargo regardless of its intended usage by importer. Therefore, even though he claimed no intention of selling or manufacturing goods out of imported material but using them personally instead did not make any difference in terms of classification for tax purposes. Consequently, the Supreme Court upheld lower courts' decisions ruling against Mr.Ewing thereby affirming that all items capable being used commercially are liable for taxes irrespective their stated purpose at time importation.

In the dissenting opinion for United States v. Ewing, Justice Harlan argued that the government had no right to seize property without due process of law. He contended that while Congress has broad power over commerce and can regulate it in any manner not prohibited by the Constitution, this does not extend to seizing private property without compensation or due process. In his view, such action is a violation of fundamental rights protected under the Fifth Amendment. Furthermore, he disagreed with majority's interpretation of forfeiture laws as being punitive rather than remedial in nature; arguing instead they should be seen as penalties imposed upon individuals who violate certain laws and thus must meet constitutional requirements for punishment including fair notice and proportionality between offense and penalty.