Why was McCarthyism able to spread so easily in the United States?

A.
The Rosenberg trial led the public to believe there were more communists in the country.

B.
Many people believed the returning army veterans were communists.

C.
The Vietnam War fueled American fears of the strength of communist control.

D.
Many of McCarthy’s accusations of communists in the army turned out to be true.

The answer is A. The Rosenberg trial led the public to believe there were more communists in the country. The trial of Julius and Ethel Rosenberg, who were accused of spying for the Soviet Union, created a widespread fear that there were communist spies and sympathizers in the US government and military. Senator Joseph McCarthy, with his accusations of widespread communist infiltration, played on this fear, and the media sensationalized his claims, allowing McCarthyism to spread easily.