I’m a little rusty on this topic, I do remember before hitler came to power Germany lost the First World War resulting in Germany being fined, and was forced to give away much of its territory. The reparations Germany had to pay literally crippled the country economically, making the german people lose faith in their leader, which resulted in hitler having a open spot to become chancellor and putting the Germans mishaps on the Jews. Hitler could have easily been stopped in the beginning when he started to use the Jews as scapegoats showing his foul intentions and bad character before he gained much of his power.
Hope that helped a little!