I totally agree @Appleblossom . I'm not holding history against anyone, we're all responsible for it, the good and the bad.  No one's hands are clean.

However I'm well aware that the Hitlers of the world happen in the places we least expect them. 

We didn't expect Hitler in Germany because it was such a cultured, educated, enlightened country. We don't expect them in USA for the reason that it's such a democratic, educated, enlightened country, but as William Scheier said those are exactly the places where they take us by surprise, because they harness the support of large social groups that aren't coping with their deep feelings of insecurity.  They're not bad people, they just can't cope with their feelings of insecurity, and to people like Hitler and Donald Trump that's a gold mine.  

That's why trying to change people minds about their beliefs and bigotries backfires.  No one wins a war against ideas, but we can say to those people "You have places where you can express your view, you don't have to express th at the expense of others."

It's not just rightwing people who feel that insecurity, leftwing people feel it, and it's every bit as frightening there too.  I have a sister who's leftwing and deeply insecure in that way, and she's not easy to get along with for that reason.  She sees anyone who's view is different from hers as a threat.  Anyone of any political persuasion can harbour such an insecurity, it's basically another expression of our humanity, but as Scheirer understood it's easily harnessed to the evil purposes those like Hitler and Stalin.