We could have had a slowly declining empire and a smooth handoff.
Instead we decided to elect a bunch of people to burn it all down and speedrun the fall of Rome.
We'll still be a world power at the end of it--in the same way France and England are world powers.
Oiy you people are boring. The US will remain a world power just due to its geographical position. It owns the Americas economically and militarily. This is something no other country in the world is close to capable of doing.