Apart from the previous Red Scare that happened prior to
World War II, the second wave of communist fear came when the Russians tested
their version of the atomic bomb and Mao Zedong conquering China. Other developments that fueled this fear was
the Korean War where the Communist North invaded South Korea and the conviction
of State Official Alger Hiss of perjury and espionage and the arrest of Julius
and Ethel Rosenberg for espionage. This gave rise to the McCarthy era where
many Americans were arrested on suspicion of being communist spies or
sympathizers.
