McCarthyism was a time period throughout the 1940's and 1950's where America was overwhelmed with concerns about the threat of communism growing in Eastern Europe and China. Emphasizing on those concerns, a young Senator named Joseph McCarthy publicly accused more than two hundred "card-carrying" communists for infiltrating the United States government. McCarthy claimed to have a list of Communists who worked in the State Department. Although his accusations remained unsupported and a Senate committee labeled them "a fraud and a hoax," McCarthy won a national following. Naming the Democrats as a party of treason, he called his political enemies as "soft on Communism". McCarthyism came to mean false charges of disloyalty.
In the Crucible, a lot of the townspeople were wrongfully accused of witchcraft. A lot of the accusations were based on unfair investigative techniques all to prove "disloyalty" to the town, or its residents. None of the information used against the accused was necessarily true, but nevertheless was still used against the people to prove wrong doings. The whole situation was based on false ideas, and was all made up to hurt and ruin reputations. Some people just wanted to get rid of others, but they picked a harmful and cruel way to do so.
McCarthyism is linked to the Crucible in the fact that both use unfair accusations to expose disloyalty or subversion. There shouldn't have been a time or a place for either to occur because it didn't do anything but hurt the people linked to it. Both were unjust, and lacked actual evidence or proof to pull of the desired "scheme". Neither should have been done or even attempted. It was a mistake in history, which only left scars on the people it wounded. It teaches a lesson for everybody to not wrongfully accuse your neighbor, because it causes complications in relationships between people and never helps out the situation.