"The most obvious casualty was the American left. The institutional toll is clear. The Communist party, already damaged by internal problems, dwindled into insignificance and all the organizations associated with it disappeared. The destruction of the front groups and the left-led unions may well have had a more deleterious impact on American politics than the decline of the party itself. With their demise, the nation lost the institutional network that had created a public space where serious alternatives to the status quo could be presented. Moreover, with the disappearance of a vigorous movement on their left, moderate reform groups were more exposed to right-wing attacks and thus rendered less effective."
I heard differently: that the dwindling of the CP was not due as much to McCarythism as to the crushing of the Hungarian uprisings ...and then dealt a definitive death blow by Krustchev's revelations.
Joanna