That's a really good scene. Really illustrates the situation.
It's the same problem Trump had, except Nixon had reason to believe he understood how the system worked, and I think Trump was surprised at the way it stood against him. JFK certainly found out how much the system stands against the president.
They used to talk about the imperial presidency, and how the office of the President gradually gained more and more power over time. Nixon's administration was sometimes said to be the peak of the imperial presidency, but it's clear he wasn't able to control the government. I think LBJ really did control the government, but that's because he was a liberal, and the deep state was in sync with what he wanted to do, unlike JFK.
Supposedly the power of the imperial presidency was trimmed back in the 70s and beyond. By the time Trump got into office, he basically had no ability to control it at all. Even if he had tried to cross the Rubicon in 2020, the entire government would have rebelled against him, including the Republican party.
I don't see how he can make it any different this time, unfortunately. The most he can do is force the deep state to grant limited concessions and ease up a bit on the satanic globohomo agenda, for a little while.