The U.S. Supreme Court case Japan Line, Ltd., et al. v. County of Los Angeles et al., 1978 revolved around the issue of whether a state could tax the cargo containers owned by a foreign corporation and used exclusively in international shipping when those containers were temporarily present in the state but domiciled abroad. The court ruled that California's ad valorem property tax violated both the Commerce Clause and International Law principles because it had an effect on foreign commerce beyond what was permissible under federal law, which has exclusive authority over such matters to ensure uniformity in dealing with foreign governments. The ruling emphasized that states cannot undermine national government policy regarding international affairs through taxation or other means.

In the dissenting opinion for Japan Line, Ltd. v. County of Los Angeles, Justice Rehnquist disagreed with the majority's decision to strike down California's tax on foreign-owned cargo containers used exclusively in international shipping. He argued that there was no constitutional basis for exempting such property from state taxation and criticized the Court’s reliance on an unratified treaty as a source of law to invalidate a state tax statute. Furthermore, he contended that it is not within the jurisdiction of courts but rather Congress or executive branch agencies to determine whether a particular state action interferes with federal government’s ability to speak with one voice when regulating commercial relations with foreign governments.