Masterson v. Herndon was a United States Supreme Court case that addressed the issue of racial discrimination in the courtroom. The case involved a dispute between two African American men, Masterson and Herndon, over a debt. Masterson sued Herndon in a Virginia court, but the judge refused to hear the case because Masterson was African American. Masterson then appealed to the Supreme Court, arguing that the Virginia court had violated the Fourteenth Amendment by denying him the right to a trial. The Supreme Court agreed with Masterson, ruling that the Virginia court had violated the Fourteenth Amendment by denying him the right to a trial. The Court held that the Fourteenth Amendment prohibited states from denying any person the equal protection of the laws, regardless of race. The Court also held that the Fourteenth Amendment prohibited states from denying any person the right to a trial by jury. This ruling was a major victory for civil rights, as it established that the Fourteenth Amendment protected African Americans from racial discrimination in the courtroom.

In the case of Masterson v. Herndon, the Supreme Court was asked to decide whether a state law that prohibited African Americans from testifying in court against white people violated the Fourteenth Amendment's Equal Protection Clause. The majority opinion held that such laws did not violate equal protection because they were based on race and not class or other distinctions. However, Justice Field dissented from this ruling and argued that any law which discriminates against individuals based solely on their race is unconstitutional under the Fourteenth Amendment's Equal Protection Clause. He further argued that it would be impossible for African Americans to receive justice if they are denied access to testify in court proceedings due to their skin color alone. Thus, he concluded that such laws should be declared unconstitutional as they deny African Americans an essential right guaranteed by the Constitution—the right of equal protection before the law regardless of race or color.