The Smith Act and HUAC were ways in which the US government could investigate/punish people associated with communism.
For example, the Smith Act made it a federal offense to organize a group that advocate for the overthrowing of the American government. The US created this act after seeing what happened during the Russian Revolution and their citizens violent overthrow of the government.
The House Un-American Activities Committee (HUAC) was a committee created by the federal government. This committee, lead by the US Congress, could call in American citizens who were suspected of being communists or worked with the Soviet Union. Being called into this committee often left a negative social stigma around a person and would sometimes lead to an individual being blacklisted.
