The Sanford v. Ainsa case in 1912 revolved around a dispute over land ownership in Arizona, which was previously part of Mexico before the Treaty of Guadalupe Hidalgo. The plaintiff, Sanford, claimed that he had purchased the land from its original owners who were granted rights by Spain and later Mexico. However, the defendant, Ainsa (administrator for his deceased brother's estate), argued that they owned it based on an old Spanish grant recognized by U.S law after Arizona became a state. The Supreme Court ruled against Sanford stating that under Article VIII of the treaty with Mexico and subsequent legislation passed by Congress to implement those provisions; all claims to lands in territories ceded by Mexico must be presented within two years to a board of commissioners appointed for this purpose or else they would be considered null and void. Sanford failed to present his claim within this period hence lost ownership rights according to US law despite having bought it from previous owners who held valid titles under Mexican rule. This ruling emphasized respect for international treaties as well as domestic laws when determining property rights.

In the dissenting opinion for Sanford v. Ainsa, 1912, it was argued that the majority's decision to deny a land grant claim based on an alleged lack of jurisdiction by Spanish courts in Arizona at the time of granting was incorrect. The dissent pointed out that Spain had undisputed possession and control over this territory when these grants were made, making them valid under international law. Furthermore, they noted that subsequent treaties between Mexico and the United States recognized such grants as legally binding. Therefore, according to this view, there should be no question about their validity or enforceability under U.S law either.