The United States Supreme Court case, UNITED STATES v. THOMAS, REGISTRAR OF VOTERS OF WASHINGTON PARISH, LOUISIANA et al., 1959 dealt with the issue of racial discrimination in voter registration processes. The federal government sued William Thomas and other officials from Washington Parish in Louisiana for allegedly denying black citizens their right to vote based on race or color. The defendants argued that they were immune from such a lawsuit because they were acting as state officers when carrying out their duties related to voter registration. However, the Supreme Court ruled against them stating that no person has immunity if he is violating constitutional rights while performing his official functions.

In the dissenting opinion for United States v. Thomas, Registrar of Voters of Washington Parish, Louisiana et al., Justice Frankfurter argued that the majority's decision to allow federal courts to intervene in state election processes was an overreach of judicial power. He contended that such intervention should only occur when there is clear and undeniable proof of a violation of constitutional rights. In this case, he believed that no such evidence existed and thus disagreed with the majority's ruling which allowed federal oversight on voter registration procedures in Washington Parish, Louisiana. Furthermore, he expressed concern about potential negative consequences from this decision including undermining states' rights and creating unnecessary tension between state and federal governments.