United States v. Adams was a United States Supreme Court case that dealt with the issue of whether a federal statute that prohibited the sale of liquor on Indian reservations was constitutional. The Court held that the statute was constitutional, and that Congress had the power to regulate commerce on Indian reservations. The case arose when the defendant, Adams, was charged with selling liquor on an Indian reservation in violation of a federal statute. Adams argued that the statute was unconstitutional because it violated the Indian Commerce Clause of the Constitution, which gives Congress the power to regulate commerce with Indian tribes. The Supreme Court disagreed, holding that Congress had the power to regulate commerce on Indian reservations, and that the statute was constitutional. The Court reasoned that Congress had the power to regulate commerce on Indian reservations because it was necessary to protect the health and welfare of the Indians. The Court also noted that the statute was not an infringement on the sovereignty of the Indian tribes, as it only regulated the sale of liquor on the reservations, and did not interfere with the tribes' internal affairs. In conclusion, the Supreme Court held that the federal statute prohibiting the sale of liquor on Indian reservations was constitutional, and that Congress had the power to regulate commerce on Indian reservations. The Court's decision established an important precedent for the regulation of commerce on Indian reservations.

In United States v. Adams, the Supreme Court was asked to decide whether a federal statute that required all vessels carrying merchandise between two ports of the same state to pay a duty violated the Constitution. The majority opinion held that it did not violate the Constitution because Congress had authority under its power to regulate interstate commerce and could impose such duties on vessels traveling within one state's boundaries as long as they were part of an overall system for regulating interstate commerce. Justice Field dissented from this decision, arguing that while Congress may have been able to pass laws related to foreign or interstate trade, it lacked any constitutional authority over intrastate trade and therefore could not impose such taxes on vessels operating solely within one state's borders. He argued further that allowing Congress this kind of control would lead down a slippery slope towards giving them too much power over states' rights and individual liberties in violation of both the Tenth Amendment and Article I Section 8 Clause 3 which grants only limited powers over domestic matters like taxation.