Final answer:
McCarthyism was primarily driven by a widespread anticommunist propaganda campaign and accusations of disloyalty.
Step-by-step explanation:
Internal context is not the main reason for McCarthyism. McCarthyism was primarily driven by a widespread anticommunist propaganda campaign directed at Cold War America by the U.S. government. It was fueled by accusations of disloyalty and unsubstantiated claims made by Senator Joseph McCarthy and other demagogues. The fear of communism and the desire to root it out from American society led to investigations, loyalty reviews, and the passing of laws that restricted political affiliation and freedom of speech.