The correct answer is the US Army.
McCarthy's reign of accusing individuals of being communism really begins in the early 1950's. After claiming he has a list of 205 members of the State Department who are known communists, he catapults to national prominence. Time after time, McCarthy accuses individuals from all walks of life of being communist. Even though he was extremely popular in the beginning of his search for communists, he became discredited due to this claims against the US Army.