Sen. Joe McCarthy was elected to the Senate in 1946 and rose to prominence in 1950 when he claimed in a speech that 205 communists had infiltrated the State Department. McCarthy soon after began to search for communists in the Central Intelligence Agency, the State Department, and elsewhere during a period in the 50's referred to as McCarthyism. During this time period, McCarthy produced a series of investigations and hearings in an effort to expose supposed communist infiltration of various areas of the U.S. government.
(From: https://www.britannica.com/topic/McCarthyism)
