Debates over Senator Joseph McCarthy and about the American Establishment illustrated the issues at the heart of the ideological battle that took place among conservative and liberal intellectuals during the 1950s and 1960s. Drawing on published materials and archival sources, this study explored the publication of four prominent books about the senator in the 1950s and intellectuals’ reactions to each and the connection of the McCarthy debate to discussion in the late 1950s and early 1960s of the Establishment. It found a direct relationship between the ideological debate over McCarthy and the development of the concept of an American Establishment.