I have always found the most trenchant insight of McCarthyism's foremost historian, Ellen Schrecker, to lie in the concluding chapter -- "A Good Deal of Trauma" -- of her magnificent Many Are the Crimes: McCarthyism in America.
As we assess the consequences of McCarthyism's assault on the left, we encounter a world of things that did not happen: reforms that were never implemented, unions that were never organized, movements that never started ... [and] questions that were never asked. We are, in short, looking at "might have beens" and at a wide range of political and cultural possibilities that did not materialize....
McCarthyism was only one of the many factors that made a new wave of reform unlikely. Still, for a few short years in the late 1940s, the American people had more political options then they would ever have again. McCarthyism destroyed these options, narrowing the range of acceptable activity and debate.
Put in another, shorter way, the crime of McCarthyism lay as much in what it subtly prevented -- socioeconomic progress -- as in what, and whom, it actively destroyed. That is, McCarthyism was an extraordinary national distraction of almost utter fabrication; it brooded, it raged, it preoccupied the country at a moment of enormous promise -- the extension of New Dealism -- and one is hard pressed to imagine that its timing was unwitting or coincidental.
I suspect that someday historians will look back on this Tea Party/Radical Right era as merely a variation on McCarthyism: the assaults on the left; the reforms stalled or killed; the questions never asked, since we consumed ourselves with the question of debt, "narrowing the range of acceptable activity and debate"; the unmaterialized political and cultural possibilities which a black, progressive president had potentially opened -- the Tea Party/Radical Right as "one of the many factors that made a new wave of reform unlikely."
I suppose there's an even simpler way to put it: The Right has always known how to press our buttons, and thus distract us from progress.