Rather than own up to their moral blindness to Soviet espionage, Democrats fired up the liberal slander machine, which would be deployed again and again over the next half century to the present day. In hiding their own perfidy, liberals were guilty of every sin they lyingly imputed to McCarthy. There were no "McCarthyites" until liberals came along. [AnnCoulter.com MCCARTHYISM: THE ROSETTA STONE OF LIBERAL LIES  November 7, 2007]
But it's not only liberals as such, it's neoconservatives, as Sam Francis noted when Ann Coulter wrote her own book on McCarthy in 2003. [The Neocons Launch A Coulterkampf, August 7, 2003 ]
For her pains, she was attacked by Andrew Sullivan,  Dorothy Rabinowitz,  Steve Hayward and Jonah Goldberg  on National Review Online, David Brooks in the Weekly Standard,  David Horowitz,  and Arnold Beichman. (Beichman's attack on her, [McCarthyism Up Close , Washington Times, August 7, 2003, pay archive], is much harder to find than her robust response to it . ) But all these people are nominally Republican.
David Horowitz wrote just recently that 
Alarms about the political subversion of the academic curriculum were first sounded more than a quarter of a century ago with such books as The Closing of the American Mind, Illiberal Education and Tenured Radicals.
Er, no. They were first sounded by conservatives in the Twenties and Thirties, continued in the Forties and Fifties, in what is called the McCarthy Era, and were being sounded really loudly in the Sixties and Seventies, when Horowitz was supporting the Black Panthers and the Viet Cong . (I have a copy of his Corporations And The Cold War  (1969) on my bookshelf somewhere.)
A "quarter of a century ago" is when Horowitz and others started to have "second thoughts."
Sam Francis said that once you understood what neoconservatism is--"a brand of liberalism  that likes to masquerade as a phony conservatism, mainly so it can wheedle influence in the Republican Partyâ€”the puzzle is solved."
That about covers it.