He may have been right in the abstract, but he went after popular figures and did so in a way that disgusted ordinary Americans. In so doing, he discredited honest conservatives, led to the election of Kennedy and Johnson, and probably Carter and Clinton.
The most underestimated American President of my lifetime was Eisenhower, who cooked this turkey in his own grease. Although I agree that communists had infiltrated the government, I cannot think of a single good thing that came out of the McCarthy hearings.
Michael Moore is a popular figure. He is also a socialist.
Nothing protects the famous or powerful from being called on the carpet (there was a House Committee On Un-American Activities at the time, commonaly misidentified as HUAC, it had its origins in an investigating group established in 1938).
Did Joe McCarthy himself lead to the election of liberals, or did the liberal/socialist establishment that counter-attacked and destroyed his reputation lead to the election of liberal Presidents? I always look at history in the context of its era. Communism had indeed infiltrated into the government, schools, business, (Armond Hammer), and even our churches, (read what Bella Dodd, a former Communist Party leader turned Catholic said about this). Communism in those days was spreading faster and more furious than AIDS and SARS combined. Suddenly a backwards peasant country like Russia had become a mighty Communist Empire, and China became Communist too. And Cuba became a surrogate Soviet State right off our coast. People were building underground nuclear bomb shelters, and public schools were sending chldren home with mimeographed evacuation plans for thermo-nuclear war. There were influential Communist parties in France and Italy, and some other Asian nations like North Korea had taken on Communist governments. Add to this the fact that even some traditionally conservative Catholic governments in South America were leaning towards socialism, and you get a much better picture of Joe McCarthy and his times. He became a convenient scapegoat becasue he was, in fact, a Roman Catholic. So hated were Catholics then, (and now), that a few years later a young, handsome, brilliant, charismatic Catholic named John Fitzgerald Kennedy, (also a war hero), had to publicly renounce his Catholicism to get elected. TWICE he was forced to publicly declare, (in W. Virginia and Texas), that he would "never allow my Catholic beliefs to get involved in public policy". Now, how many Protestant Presidential candidates felt compelled to make similar statements about their faith? NONE. Look how they have marginalized and ostracized poor Pat Buchanan, who has been right far more than he has been wrong. Joe McCarthy was right. Maybe his tactics were wrong, but HE was right.