Comment by ElProlactin

> ...and they've done a pretty good job of that up until ~this year.

Not really.

When you look back, seeing how things turned out, history looks different than it almost certainly felt to most people at the time.

It took 250-300 years for the Roman Empire to collapse. You could make a pretty strong argument that the US has been in decline for decades, and that cracks in Pax Americana were already forming during the Vietnam War era.