The relationship between Marshall and Hoover, however, evolved into a type of begrudging respect (and maybe some form of friendship) over time. Apparently the pair shared an intense dislike for communists. This was after World War II, when fears about communists infiltrating America reached a fever pitch known as the Red Scare. Marshall tipped off the FBI about possible communists within the NAACP. Hoover “was convinced that I was responsible for routing the commies out of the NAACP. And I did,” Marshall once said, according to the Thurgood Marshall website. He wanted to protect the civil rights organization from communist influence.

Marshall also gave information to the FBI about more militant members of NAACP, including Robert Williams, an activist whom History describes as advocating that people “take up arms to gain African American rights.” Marshall’s willingness to leak some items to the agency may also reflect his skill as a political strategist. Marshall had the support of Hoover as Marshall sought judicial appointments, becoming a circuit judge in 1961. In 1967, Marshall made history as the first African American to be appointed to the U.S. Supreme Court (via The Baltimore Sun).