As M. Stanton Evans irrefutably demonstrates, McCarthy “didn’t make a practice of frivolous accusations about communism” either.
Meroney’s claims to the contrary notwithstanding, J. Edgar Hoover strongly supported McCarthy. As the FBI director put it in 1953:
“McCarthy is a former Marine. He was an amateur boxer. He’s Irish. Combine those and you’re going to have a vigorous individual, who won’t be pushed around ... Certainly, he is a controversial man. He is earnest and he is honest. He has enemies. Whenever you attack subversives of any kind,... you are going to be the victim of the most extremely vicious criticism that can be made.”
-Blacklisted by History, p. 36
Good point that Hoover apparently supported McCarthy, as late as 1953.
But Hoover later quietly opposed him, according to Meroney:
“In 1954, during Senate hearings to determine whether McCarthy had pressured the Army to give special treatment to one of his former aides, G. David Schine, Hoover let McCarthy twist in what were already rough winds. He refused to come to McCarthy’s defense on the matter of mysterious documents about the security of an Army installation that appeared to be written by Hoover. Hoover denied their authenticity, which embarrassed McCarthy and his counsel, Roy Cohn.”
According to Meroney, McCarthy was reckless, to put it mildly:
"In 1950, McCarthy infamously said he had a list of more than 200 communists who had "infested" the State Department and were shaping its policy—claims he could never prove. He also insinuated that Secretary of State Dean Acheson and Gen. George Marshall were traitors. Those familiar with the techniques of the party later recognized the irony in the fact that McCarthy used the same kind of dishonest tactics—grandstanding, fomenting internal political division, confusing issues on purpose and vilifying those who stood in his way—that had been mastered by the communists."