What lessons should have been learned and implemented from the rise of Hitler and the Nazis in their ascension to power to prevent a recurrence of similar actors and ideological campaigns in future?
hitler got into power because their moderates refused to appeal to their leftist voters and supported facism and so hitler's side won the election and, later, the country after they disenfranchised the moderates and executed the leftists; right now it's looking like americans are going to follow suit.
i can only speak for the western world since that's what i learned about as an american and there's a recorded history of punching left significantly harder than punching right.