Mead v. Thompson was a United States Supreme Court case that dealt with the issue of whether a state could deny a person the right to vote based on their race. The case was brought by a black man, William Mead, who had been denied the right to vote in the state of Mississippi. The Supreme Court ruled in favor of Mead, holding that the state of Mississippi had violated the Fourteenth Amendment of the United States Constitution, which guarantees all citizens equal protection under the law. The Court held that the state could not deny a person the right to vote based on their race, and that the state must provide equal protection to all citizens regardless of race. The ruling in Mead v. Thompson was an important step in the fight for civil rights in the United States, and it set a precedent for future cases involving racial discrimination.

In the case of Mead v. Thompson, Justice Field delivered a dissenting opinion in which he argued that the majority's decision was too broad and should be limited to cases involving federal land only. He noted that Congress had not intended for its laws to apply beyond those lands, and thus it would be improper for them to do so. Furthermore, he argued that if the Court were to extend their ruling beyond federal lands then they would essentially be creating new law rather than interpreting existing ones as is their duty. In conclusion, Justice Field believed that by extending this ruling beyond federal land it could lead to confusion and uncertainty regarding what rights individuals have when dealing with state or private property matters.