In the 1946 case Clark, Attorney General, as Successor to the Alien Property Custodian v. Allen et al., the United States Supreme Court ruled on a dispute over property rights of German nationals in America during World War II. The Alien Property Custodian had seized assets belonging to German citizens under the Trading with Enemy Act and was sued by heirs who were American citizens claiming that they should inherit these properties instead. The court held that while U.S. law did not prevent an alien enemy from inheriting real or personal property, it did allow for seizure of such inherited property if it belonged originally to an enemy national at war with America. Therefore, even though American heirs could technically inherit their relatives' estates under California state law where this case originated from, federal wartime laws superseded those inheritance rights allowing for seizure of said properties.

In the dissenting opinion for Clark v. Allen, Justice Frank Murphy argued that the majority's interpretation of Section 9(a) of the Trading with Enemy Act was incorrect and overly broad. He contended that this section should not be used to validate claims by American citizens against foreign governments or their nationals unless there is a clear congressional intent to do so. According to him, such an expansive reading could lead to serious international complications and conflicts with other nations' sovereignty rights. Furthermore, he believed that it would be more appropriate for these types of disputes involving property rights in wartime situations to be settled through diplomatic negotiations rather than judicial proceedings.