After we found out that the soviets had the atomic bomb, we became increasingly sensitive about threats to internal security. how did this feeling pave the way for mccarthy's red scare?

Basically, people were afraid that the Soviets might decide to nuke the United States. McCarthy showed up claiming that he had lists of people who were known communists in the United States and who were spying for the Soviet Union or at least supported its victory. Many people believed him and the red scare grew even more.