> The US is an empire (and the mightiest one yet) and will act like that until it isn't capable to do so any more. Historically, that's around 100 more years but I'm not sure history is predictive here.

Agreed, but one thing that has been a constant throughout history is that empires eventually become complacent and buckle under their own weight, and have to face smaller contenders that don't have the inertia to maintain the status-quo.

It's telling that there really isn't any empire that has endured "forever", probably because this is simply not possible.

Portugal was the first global empire and ostensibly lasted for 600 years, but its decline started much sooner than it's total lifespan (around the 200 year mark). The country is now a shadow of what it once was, and the US will also be one day.