Until Hitler’s rein of terror got into high gear and the rest had no choice if they valued their lives but go get with the program, only about 40% of the population backed him. This is about the same number that currently support Trump.
Now while it is certainly true that America has a far stronger history of democratic rule, the reality is that every society has within it the potential for a Nazi type State under the right conditions, and those conditions are already in place here in the good old US of A.
All the nation’s bad eggs have over the last few decade migrated to the same political party — the Republican Party. They have taken control of the party and found a leader in Trump. Because it was so profitable, a right wing propaganda machine has come into existence in the form of talk radio and Fox”News.” The old establishment like Paul Ryan and Mitch McConnell are whistling past the graveyard if they think they have a future as party leaders. The base controls the party and Trump controls the base.
All that stands between a fascist dictatorship are the courts and about 55% of folks who understand and appreciate democracy. The super rich and corporate powers will simple go whichever way they see the big bucks. Trump has a long history of finessing the monied set.