1940s. U.S. Senate career Ervin was appointed to a seat as an associate justice of the North Carolina Supreme Court vacated by the resignation of Michael Schenck, and was serving in that capacity when he was appointed in June 1954 by Governor William B. Umstead to fill the U.S. Senate seat of Clyde Hoey, who had died in office. He ran successfully for the seat in November 1954. Ervin made a deep impact on American history through his work on two separate committees at the beginning and ending of his career that were critical in bringing down two powerful opponents: Senator Joe McCarthy in 1954 and President Richard M. Nixon in 1974. In 1954, then-Vice President Richard Nixon appointed Ervin to a committee formed to investigate whether McCarthy should be censured by the Senate. The Senate Select Committee to Investigate Campaign Practices, which investigated Watergate, was popularly known as the "Ervin Committee". In 1956, Senator Ervin helped organize resistance to the 1954 Brown v. Board of Education Supreme Court decision calling for desegregation of schools by drafting The Southern Manifesto; this influential document encouraged defiance of desegregation and was signed by all but a few of the Southern members of Congress. (In his autobiography, Preserving the Constitution, Ervin said he later changed his mind on the Brown decision, stating that the decision, to the extent it eliminated mandatory segregation, was correct, but that forced integration, required under later decisions, was improper.) Defenders of Ervin argue that his opposition to most civil rights legislation was based on his commitment to the preservation of the Constitution in its pristine formulation, and a general belief that the Equal Protection Clause of the Constitution only applied to white men. He repeatedly stated that the Constitution encapsulated civil, human and equal rights for all those he considered worthy. There is little if any evidence that he engaged in the racial demagoguery of many of his Southern colleagues. Some historians consider Ervin's position to be one of "cognitive dissonance" because he opposed federal legislation to combat race-based discrimination, but did not do so in harsh terms. While he once maintained that Americans were entitled to "their prejudices as well as their allergies", Ervin's defendants claim he did not seem to be motivated by prejudice himself, but more by his suspicion of federal power. Ervin said he disliked what the Warren Court "has done to the Constitution".