In the United States v. Barlow case of 1901, the Supreme Court ruled on a dispute regarding land ownership in California. The plaintiff, the U.S government, claimed that certain lands were part of public domain and thus belonged to them while defendant Barlow argued that these lands were private property under Mexican law before California became a state and should therefore remain so. The court held that when Mexico ceded California to the U.S., all unallocated or unsettled lands automatically became federal property unless proven otherwise by claimants like Barlow through valid land grants from Spanish or Mexican authorities prior to 1848 (Treaty of Guadalupe Hidalgo). In this case, evidence showed no such grant existed for Barlow's claims; hence his argument was rejected. This decision reaffirmed previous rulings about territorial changes following war treaties where new sovereigns gain control over all public properties except those legally owned privately.

In the dissenting opinion for United States v. Barlow, it was argued that the court had overstepped its boundaries by interpreting a law in a way not intended by Congress. The justice disagreed with the majority's interpretation of an 1891 act which allowed settlers to purchase land at $2.50 per acre if they were unable to irrigate it for agricultural purposes due to lack of water supply or other reasons beyond their control. According to this view, the act did not intend for individuals who could afford irrigation but chose not to do so because of economic considerations, such as Barlow, be able to buy land at reduced prices meant for those truly incapable of irrigation due to natural limitations or financial incapacity.