To refine the topic, maybe you could base your essay on answering one of the questions following:
Was the McCarthy witch-hunt justified?
Was the McCarthy witch-hunt beneficial for the US?
Would it have happened WITHOUT McCarthy? (Was it really a political fight, or a personal vendetta?)
What made M. decide to...?
Did M. represent public opinion re Communists?
Is M. just a product of his times?
Did M. represent the interests of the state ofWisconsin?
What issues motivated M., was it more than just anti-Communism?