WW2 caused an aberration in American politics where fascism, and literal nazi's, were shunned for generations. But there were violent anti-labor groups active in American prior to WW2. There were pro-Hitler rallies in America prior to the US entering WW2. Extreme right wingers have always been a part of American history. It just took 60 years for them to overcome the natural repugnance caused by WW2 and start openly proliferating again.
