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.
Put your hand up their ass and wiggle your fingers just right and you can get a bigot/moron to do whatever you want.