Hitler used division of parties and ideologies to continue the fervor which supported and fueled the Nazi party. History unfortunately shows that society forgets, not learns, civic lessons... especially when surrounded by pain. We are a cyclical, non-learning species. Realizing that is only the beginning of doing the right thing.
http://www.slate.com/articles/news_and_politics/fascism/2017/03/how_nazi_propaganda_encouraged_the_masses_to_co_produce_a_false_reality.html
"Hitler understood, as few others had ever done, the need for the serial creation of enemies. He was a political entrepreneur possessed of the truly devastating insight that all recent enemies could eventually merge into the one super-enemy, the Jews. Here was an intuitive understanding of how self-definition is achieved through other-rejection, that solidarity, identity, and community are in essence gained at the expense of others and appeals based on the brotherhood of man (as, in a sense, even Communism did) would always ultimately fail. His construction of tribal passion could arouse the emotions and therefore render people vulnerable to any kind of visionary persuasion or invocation to epic quest."
Sounds almost exactly like what is going on today. Do not be fooled.
