I should have added The Turner Diaries, as it’s a major inspiration for the Right. It’s just that the RL ending will be “nukes fall, everyone dies” instead of “white nationalists rule the world forever”.
In 1935, It Can’t Happen Here by Sinclair Lewis captured the current zeitgeist. Hint: it’s not an optimistic future.
There’s a YA novel, The House of the Scorpion , which features a diminished United States whose top political figures curry favor with the richest man in the world, El Patron, a ghoulish narco-trafficker who is the head of state of a new country, Opium, which occupies a strip of land on the US/Mexico border. If you’ve read the book, you might see a plausible reason Elon Musk has for fathering over a dozen children. Anyway, this book gets my vote.