When was the last time a country actually collapsed? You’ve got Yugoslavia, Cambodia, Lebanon, Afghanistan, Yemen, Libya, Somalia, and the USSR. Forgoing the USSR, you don’t see many countries of this size doing the whole “collapse” thing, these days. I think it’s far more likely that worst case scenario tends toward reshaping American culture toward more toxicity, corruption, … other nations will slowly stop relying on the US for its economic reliability, stable bonds, … you’ll have less sway over international politics. Locally, your markets will lose the vigor provided when an economy yields fair chance to make gains. People who rise to power in your new nation will be those who pay or promise the most to a small handful of elitists. National response to disasters will become dull. People will be radicalized, but also less educated. Public violence will increase. All of this will happen while your foreign state enemies watch and fill the void you’ve left. You’ll never get that position back… just as Rome didn’t. Just as Spain didn’t. Just as the UK didn’t. You’ll be a nation that just fades to the sidelines. Still relevant in some ways, but definitely not anything like you used to be.