United States v. Reisinger was a Supreme Court case decided in 1880. The case involved a dispute between the United States and a private citizen, John Reisinger, over the ownership of a parcel of land in the state of California. The United States had acquired the land in 1851, but Reisinger had been in possession of the land since 1854. The Supreme Court held that the United States had acquired the land in 1851 and that Reisinger had no valid claim to the land. The Court also held that the United States had the right to eject Reisinger from the land and that Reisinger was not entitled to any compensation for his improvements to the land. The decision was unanimous and established the principle that the United States has the right to acquire land for public use without compensating private citizens for their improvements.

In the dissenting opinion of United States v. Reisinger, Justice Harlan argued that Congress had no authority to pass a law prohibiting the sale of liquor in Indian country as it was not within its power to regulate commerce with foreign nations or among states. He further argued that this prohibition violated the Fifth Amendment by depriving individuals of their property without due process and constituted an unconstitutional exercise of police power. Additionally, he noted that while Congress could impose regulations on Indians living in tribal areas for their own protection, such regulations must be reasonable and consistent with existing treaties between tribes and the federal government. In conclusion, Justice Harlan believed that Congress did not have constitutional authority to enact laws regulating alcohol sales in Indian country as it would violate both treaty obligations and individual rights under the Constitution.