How did McCarthyism limit the actions non-communists could take?|

Non-communists were unfairly accused

Explanation:

McCarthyism - a vociferous campaign against alleged communists in the US government and other institutions carried out under Senator Joseph McCarthy in the period 1950–54. Many of the accused were blacklisted or lost their jobs, although most did not in fact belong to the Communist Party.

Therefore, the McCarthyism's limited the actions of non-communists, who had to be cautious, as to not be listed, as a "commie."