What general factors made the United States susceptible to the anticommunist paranoia of 1947 to 1953? What activities fanned the fury and paved the way for the rise of Joseph McCarthy?

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.