The Atlanten case in 1919 involved a dispute over the seizure of a Norwegian ship, The Atlanten, by the United States during World War I. The U.S. had seized the vessel under its right as a sovereign nation at war to prevent supplies from reaching enemy nations. However, Norway was neutral during WWI and argued that this seizure violated international law regarding neutrality rights. The Supreme Court ruled in favor of Norway stating that while countries at war have broad powers to seize vessels suspected of aiding their enemies, they must provide compensation if it turns out those suspicions were unfounded or incorrect after due process is given. This ruling reinforced principles of international law and respect for neutrality rights.

In the dissenting opinion for The Atlanten case, Justice McReynolds disagreed with the majority's decision to uphold a lower court ruling that allowed an American company to sue a Norwegian ship in U.S. courts. He argued that this violated international law principles of comity and respect for foreign sovereignty because it involved applying domestic laws to foreign entities without their consent or presence in the country. Furthermore, he contended that such actions could lead to retaliatory measures from other nations and potentially harm U.S.-foreign relations. Therefore, he believed that unless there was clear evidence of wrongdoing by the Norwegian ship or its crew within U.S. jurisdiction, they should not be subject to lawsuits in American courts.