I would start by looking up American responses to the Russian revolution, which led to the "First Red Scare".
Also - any chance you have read The Crucible in any English classes? Either way, the play was written by Arthur Miller, an American playwright who suffered persecution during the Second Red Scare for alleged communist sympathies. The Crucible is set in Salem during the infamous witch trials of the seventeenth century and is meant to be read as an extended allegory for the Second Red Scare. So, you may want to also look up the Salem Witch Trials to help answer this question.