Who played a key role in the spreading of anti-communist hysteria?

Joseph McCarthy was one of the main culprits of spreading anti-communist hysteria in American society. This concept, known as McCarthyism, spread like wildfire throughout America in the 1950's. Joseph McCarthy made several claims during this era that spread hysteria. This included accusing hundreds of members of the US State Department of being communist. McCarthy went as far as accusing members of the US military as being communists. This last accusation resulted in his political downfall.