Jason JewellCSA, that’s the pattern in the Ancient Near East, at least, with the exception of Egypt, which managed to maintain a continuous existence longer than anyone else despite occasional periods of internal instability and one or two invasions.
I don’t know to what extent we can draw analogies with the 21st-century U.S. The ideologies of democracy and self-determination are present today to a far greater extent than in the ancient world, and that makes it extremely difficult for a would-be imperial power to maintain sway, particularly when that power is reluctant to use violence in as naked a fashion as some group like the Assyrians.
A military takeover of the US by someone else seems impossible for the foreseeable future, barring an extraterrestrial invasion. The big threat to the US empire is economic. We’re dependent today on highly developed capital structures unknown in the ancient world, and we seem to be de-capitalizing right now with all the borrowing and spending on social programs.
I hope these off-the-cuff thoughts help you think through this question. It’s certainly worth pondering.