I laughed when I read this paragraph from the History of the Communist Party

[limpyhobbler]

8. Ya know it's true there was a real turning point somewhere, and we went

down the wrong path. Like you say the train maybe went of the tracks by the 1920s.

Makes sense. There were a few big battles later on of course, during the 30's and the Flint sit down strike, stuff like that. But it seems like the (first) Red Scare was when the capitalists really decided to stomp out the radical element once and for all. They took the propaganda machine and ideology police that were developed to keep the public in line for World War I, and they turned those tools against the labor movement and the Communists and socialists in general. They saw what happened in Russia and it scared them.

And to a large degree they were successful in stamping out real resistance of the kind that really questioned the system. Everything after that has been sort of an epilogue of what happens after a nascent radical movement is crushed. All these past decades we've been living in the burnt ruins of a failed revolution. Or something along those lines. And the taming of the unions was clearly a big part of it.