America is not and never has been an “Empire”. No one with a brain could believe that, if we wished, we could not have conquered all of North and South America with little effort. We haven’t. We could have taken over large swaths of Europe and the Middle East after WW2. We didn’t; we helped them rebuild. We WOULD DEFINITELY have taken control of Japan. We didn’t.
You’re welcome to replace empire with country, original form of government, or otherwise. We’ve never been a traditional empire, but that doesn’t mean we’re not at the same risks as actual empires.