Read the Venona transcripts, it proves it. Also, the Russians admitted as much after the fall of the Soviet Union. Honestly, this is basic history, the only reason it isn't covered the way it should be is because of the left controls academia and has been soft to communist. McCarthy was also relentlessly attacked by the media for his anti-communist statements in the 1950s. Because of this, McCarthy is viewed as some paranoid nut who overreacted to the fact that there were Russian spies in the United States government (backed by FBI investigations). Today the red-scare is viewed as a bad event in history; however, it was 100% justify considering the Soviets and communist would eventually end up killing tens of millions around the globe.