Answer:
In the 1950s, Americans were afraid of communism because of the widespread belief that communist ideology would infect the country and persuade citizens to turn against democracy and capitalism. This rampant fear and suspicion caused many people to dread not only communism, but being accused of communist sympathies themselves. Americans also feared communism in the form of the Soviet Union, a communist, rival country which had proven itself a viable military threat through its nuclear weapons program.