I wouldn’t exactly call McCarthy a hero. He was a politician who sought to capitalize on the revelations of Whittaker Chambers and another ex-Communist spy named Elizabeth Bentley. Chambers and Bentley brought to light Communist penetration of the American government. McCarthy tried to use it for his own benefit.
If he had been more careful in his accusations he might have survived the attacks from the Left. But he wasn’t careful and he made irresponsible accusations like accusing Eisenhower’s WWII boss, General George Marshall, of being a Communist dupe. This earned him some powerful enemies who weren’t going to put up with his nonsense. And when McCarthy decided to hold an investigation of the Army Signal Corp they took the opportunity to take McCarthy apart.
Most of his accusations were spot on.
He was a hero. Our government was riddled with Soviet agents, and nobody gave a damn.
He was the only one of a very few who stood up and put himself on the line. I don’t buy the liberal line that McCarthy did it for himself and only his own gain. He took on the powers at the time who all wanted to ignore it because it was inconvenient and impolitic.
It is a liberal smear, put forth by the same media that did a 24x7 effort for nearly four solid years without relief to discredit him.
As for Marshall, it depends on what you mean by a communist “dupe”. Marshall was an intelligent guy, and some of the things he advocated in both war and peace make me wonder why he proposed and supported them. To be kind, I would say Marshall was a liberal dupe.