Robert Marion La Follette Jr. was an American politician who served as United States senator from Wisconsin from 1925 to 1947. A member of the La Follette family, he was often referred to by the nickname "Young Bob" to distinguish him from his father, Robert M. "Fighting Bob" La Follette, who had served as a U.S. senator and governor of Wisconsin. Robert Jr., along with his brother Philip La Follette, carried on their father's legacy of progressive politics and founded the Wisconsin Progressive Party. Robert Jr. was the last major Progressive Party politician in the U.S. Senate, ending in 1946 when the party disbanded. La Follette was defeated in the 1946 Republican Senate primary by Joseph McCarthy.

Joseph Raymond McCarthy was an American politician who served as a Republican U.S. Senator from the state of Wisconsin from 1947 until his death at age 48 in 1957. Beginning in 1950, McCarthy became the most visible public face of a period in the United States in which Cold War tensions fueled fears of widespread communist subversion. He alleged that numerous communists and Soviet spies and sympathizers had infiltrated the United States federal government, universities, film industry, and elsewhere. Ultimately, he was censured for refusing to cooperate with, and abusing members of, the committee established to investigate whether or not he should be censured. The term "McCarthyism", coined in 1950 in reference to McCarthy's practices, was soon applied to similar anti-communist activities. Today, the term is used more broadly to mean demagogic, reckless, and unsubstantiated accusations, as well as public attacks on the character or patriotism of political opponents.