This was written in the book Star Trek Memories by William Shatner and made me pause. But today we are seeing it happen in real time in America and yet no one is truly trying to stop it. So with this we can see exactly how it could happen then.
Hell the media alone refuses to acknowledge we have Concentration Camps in the states.
The Nazis were inspired to create concentration camps by the US racial policies against black, jewish and asian communities. So, there’s that.