In the 1920 case of Port of Seattle v. Oregon & Washington Railroad Company, the Supreme Court was asked to determine whether a port district in Washington had the authority to condemn land owned by an interstate railroad company for public use. The court ruled that under eminent domain laws, a state or local government could take private property for public use if just compensation is provided. However, this power does not extend to taking property from another state or its political subdivisions without consent. In this case, since railroads are considered instrumentalities of commerce and thus federal entities, they cannot be subjected to condemnation proceedings initiated by states or their subdivisions without congressional approval. Therefore, it was held that the Port of Seattle did not have legal authority to seize land owned by Oregon & Washington Railroad Company as it would interfere with interstate commerce.

In the dissenting opinion for Port of Seattle v. Oregon & Washington Railroad Company, Justice McReynolds disagreed with the majority's decision that allowed a public port to condemn land owned by a private railroad company for its own use. He argued that this was an overreach of eminent domain powers and violated property rights protected under the Constitution. According to him, while it is true that public ports have been given certain privileges in order to facilitate commerce, these should not extend so far as to allow them to seize privately-owned lands without just compensation or due process. Furthermore, he contended that there were other ways for the port authority to achieve its goals without resorting such drastic measures - they could negotiate with existing owners or seek alternative locations instead of forcibly taking away someone else’s property.