Answer:
✔️They feared communist takeover and nuclear warfare.
Step-by-step explanation:
People were so afraid in the 1940s and 1950s because "they feared communist takeover and nuclear warfare".
A hysteria was sparked up in the late 1940s and 1950s which was known as the Red Scare. It was as a result of of the perceived threat that was posed by the Communists in the United States. This took place during the Cold War between the Soviet Union and the United States. The fear at that time had an enduring effect on U.S government and society. They feared that Communist will takeover.