Trustee from 1947 to 1950. Elected to the Senate in 1925 as a Republican to fill the vacancy caused by the death of his father, Robert M. La Follette, Sr. A champion of organized labor, La Follette gained national prominence between 1936 and 1940 as chairman of a special Senate investigating committee, commonly called the La Follette Civil Liberties Committee, which exposed techniques used to prevent workers from organizing. Co-founder of the Wisconsin Progressive Party, he was re-elected to the senate twice as a Progressive. He returned to the Republican party for the 1946 election, but narrowly lost a primary race to Joseph McCarthy.