I think the issue many people have with fascism is they think it happens overnight with a declaration. It happens more slowly than that where previously unacceptable behaviour becomes more normalised. Then once one normal is formed another is transitioned to.
The Star Wars prequel trilogy is probably the best modern day example of this. Emperor Palpatine doesn’t become leader overnight. He rides to the rescue as new chancellor against a (manufactured) crisis.
The stormtroopers are initially there for good to save the Republic. Just as the Jedi were. The Jedi’s religion became grey as it involved itself in war. The stormtroopers became a vehicle for suppression and the Jedi’s were a radicalised religion. Emperor Palpatine became a God.
And although the Star War Prequel trilogy spans 3 short movies – it’s supposed to span 32 years, 19 years before the Original Trilogy.