You can criticize the Joe McCarthy in his approach to the problem of Communists in our midst, some with governmental authority, but you really can't ignore the fact that he was right in his assessment of the real threat of communist subversion.
Wasn't just his approach; he went after thousands of innocent people, and (perhaps inadvertently) in the Fort Monmouth "investigation" helped some real Soviet spies escape when he went after innocent people, giving the real spies cover long enough for them to safely flee. In once case, he attacked a scientist working there as a communist, because the scientist's brother had decades ago, attended a meeting where Paul Robson had spoken, and the scientist knew his brother.
McCarthy made his critical error in claiming the U.S. Army was riddled with communists, when the Army resisted his efforts to give G. David Schine (a "close friend" of McCarthy's aid Roy Cohn) special privileges as an enlisted man. At the hearings, Joseph Welch, the lawyer for the Army dismantled McCarthy in a notable exchange:
"Senator, may we not drop this? We know he belonged to the Lawyer's Guild ... Let us not assassinate this lad further, Senator; you've done enough. Have you no sense of decency, sir? At long last, have you left no sense of decency?"
Exposed on national television, McCarthy was eventually censured and died in well-earned disgrace.
Had it not been for the Republicans, President Johnson would have never been able to get his Civil Rights Act of 1964 to his desk to sign.
Had it not been for the liberals and moderates. Every liberal and moderate voted for it, regardless of party. Nearly every conservative voted against it, regardless of party. Barry Goldwater at least took a principled stand, refusing to support it on Constitutional grounds. He was wrong, but he wasn't a racist.
It was a confrontation between liberals and conservatives, and the liberals won. It is, ultimately why conservatives left the democrat party and became republicans.
Until the 1960s, the democrats were the party of segregation. It wasn't until Nixon's southern strategy that racists left the democrat party en masse. Today, the republicans have that vote secured, and their base of power is in the old south formerly held by democrats.
Things change. What didn't change was the difference between liberals and conservatives regarding civil rights.