Hitler outlawed all opposition parties in July 1933 and opened concentration camps for political opposition right away. The official boycot of Jewish businesses started that year and the regime started to strip them of citizenship.
It was not gradual. It was gradual only if you was apolitical or supporter.
The fact is, America has way better and stronger democracy then Germany back then. America is not perfect, but Germany back then was way more massively dysfunctional and violent place.
I am not saying America is perfect or can't be destroyed as democracy, but it would be significantly harder.
It was not gradual. It was gradual only if you was apolitical or supporter.