In March of 1945, the US Army issued this "fact sheet" to guide conversations with soldiers on the topic of fascism, paying particular attention to the ongoing threat that domestic fascist movements posed to the US. Their analysis of what a homegrown US fascism would look like is interesting.
The central point is that when fascism came to America it wouldn't call itself that, nor would it be wearing a swastika. It would call itself "patriotic" and "100% American."
The first fascistic tactic to look out for is a hate campaign against a particular religious, racial, or ethnic group. Like, for example, let's say a candidate emerges who calls all people of one nationality "rapists" and "criminals," while promising to ban immigrants from only one religious group.
The second fascistic tactic to look out for is anyone who tries to amp up nationalistic animosities toward other nations or peoples, framing attempts to foster international cooperation as forms of weakness. The idea that all humans share the earth as equals is anathema to fascists.
The third fascistic tactic to watch out for is their tendency to label anyone they disagree with who is to their left "a Communist." Fascists claim that they alone can save their nations from "the communist menace." Anyway, the 2024 GOP platform contains the phrase "Christ-hating communists."

https://archive.org/details/ArmyTalkOrientationFactSheet64-Fascism/mode/2up?view=theater