McCarthyism is Americanism with its sleeves rolled.

Meaning of the quote

This quote means that McCarthyism, which was a period where people were accused of being communists without much evidence, was actually just an extreme version of American patriotism. The idea is that McCarthyism took American values and pushed them to an extreme, like someone rolling up their sleeves to get a job done. It suggests that McCarthyism was a distortion of true American ideals.