Sadly, I agee with you - I see the Sacco and Vinzetti trial as the turning point. We’ll never get a foothold there - the Right abandoned culture generations ago.
All this I find just today, reading up on it. Most interesting to me is the developing history of the commemeration of the event. Originally, there was a monument to the slain policemen ( said now to be mostly victimes of "friendly fire" ) but this monument suffered continued vandalism, and was driven over the years out of existence. Now just in 2004, a monument has been erected at the site of the "riot" in Chicago. It's a modernist sculpture along the sidewalk on DesPlaines Avenue in Chicago. The whole ruckus was over the establishment of an eight hour work day, so think about that.