It becomes normalised, the window shifts, and it has already shifted a lot.
Things that were unthinkable to be done or said by politicians 15 years ago now happen almost daily. Speeches that would be scandals are just another drop in the bucket, rhetoric that would've crashed careers, and get people in absolute shock now became celebrated.
You just have to remember you aren't going crazy, this is not normal and shouldn't be normal, the window just shifted so much that a lot of people learnt to agree with it, for their own reasons, by manipulative tactics.
“I’ll tell you something that’s going to get me in trouble, but I couldn’t care less,” the president responded. “The radicals on the right oftentimes are radical because they don’t want to see crime. They don’t want to see crime.”
“They’re saying, ‘We don’t want these people coming here. And we don’t want you burning our shopping centers. We don’t want you shooting our people in the middle of the street,’”
Even at America's lowest points (Fugitive slave act, Bleeding Kansas, Japanese internment) this is not something Americans would have tolerated of their federal government.
I feel the need to remind people that Americans labelled Hitler a tyrant and were willing to march to the death to Berlin before they even knew about the concentration camps.
Really drives home that the median American is a bloodthirsty nazi freak.
This is probably a tad too cynical, but I think it was the attack on Pearl Harbor, by an ethnic and culturaly distinct nation that solidified "the great other" as an enemy. It allowed the nation to overcome the pro-fascist forces which were also present at the time. Racist propaganda alongside a sense of besiegement bound together the nation. You saw the same thing with 9/11.
I hope that room full of generals and master chiefs in Quantico agreed to secretly back-channel with each other such that they have a "break glass" plan of mass refusal to execute illegal orders per UCMJ.