In the 1904 case of Amado v. United States, the U.S. Supreme Court dealt with a dispute over property rights in California that originated from Spanish and Mexican land grants before California became part of the United States. The plaintiff, Jose Antonio Amado, claimed ownership to certain lands based on an alleged grant by Mexican authorities in 1846. However, his claim was rejected by both lower courts and eventually reached the Supreme Court. The main issue revolved around whether or not there was sufficient evidence to prove that such a grant had been made according to Mexican law at that time. The court found no substantial proof supporting Amado's claims; instead it held that he failed to establish any right or title under Mexico’s laws prior to its cession of California. Furthermore, even if such a grant existed as per his assertion but wasn't presented for confirmation within two years after Treaty of Guadalupe Hidalgo (which ended the war between Mexico and US), it would be considered void under American law which governed these territories post-war. Therefore, due to lack of convincing evidence about existence of said land grant and failure in timely presentation for confirmation (if it ever existed), Mr.Amado's claim was dismissed by Supreme Court affirming previous rulings against him.

The dissenting opinion in the case of Amado v. United States argued that the majority's decision to uphold a lower court ruling, which allowed for the seizure and sale of property owned by Mexican citizens during wartime, was unjust. The dissenters believed that this violated international law principles protecting non-combatants' property rights during conflict. They also disagreed with the majority's interpretation of an 1848 treaty between Mexico and America, arguing it did not provide explicit permission for such seizures. Furthermore, they contended that even if such permission had been granted implicitly through silence on this issue in the treaty text, it should be interpreted restrictively rather than expansively due to its potential impact on individual rights. Finally, they expressed concern about how this ruling could negatively affect future relations between nations by setting a dangerous precedent regarding respect for foreign nationals' property rights.