Newell v. Nixon was a United States Supreme Court case that was decided in 1866. The case involved a dispute between two parties over the ownership of a piece of land in the state of Missouri. The plaintiff, Newell, claimed that he had purchased the land from the defendant, Nixon, in 1859. Nixon, however, argued that he had never sold the land to Newell and that he still owned it. The Supreme Court ultimately sided with Newell, ruling that he had indeed purchased the land from Nixon in 1859. The Court found that Nixon had made a valid contract with Newell and that he had failed to fulfill his obligations under the contract. The Court also found that Nixon had failed to provide Newell with the deed to the land, which was necessary for Newell to prove his ownership. As a result, the Court ruled that Newell was the rightful owner of the land.

In Newell v. Nixon, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving federal officers and property. The majority opinion held that the state court did not have jurisdiction in this matter because it involved federal officers and property, which are under exclusive control of Congress. However, Justice Field dissented from this decision on the grounds that there is no constitutional provision preventing states from exercising their judicial power over cases involving federal officers or property when such matters arise within their borders. He argued that if Congress wanted to limit state courts' authority in these matters they would need to pass legislation explicitly doing so; otherwise, states should be allowed to exercise their usual powers of adjudication as provided by law. Furthermore, he noted that allowing states some degree of oversight over these matters could help ensure uniformity among different jurisdictions and prevent any one branch of government from becoming too powerful at the expense of another's rights or interests