We had just fought a war with Spain and took territories from them by the time WW1 rolled around. Did we call ourselves an empire? No. Did we act like one in all but name only? Yep. As you rightly mention the Indians and Mexico before Spain.

Yes we could have been self sufficient because of the natural bounty. We agree on that. Our industrial capacity grew with the advent of war in Europe. The US warmed up war making capacity with the lend lease program and went into full mobilization after pearl.

It’s at least a little interesting though that no one bombed our factories. No one bobbed our munitions plants. We could crank out materiel because of all the things we’ve talked about ad nauseum with regard to geography. The Germans couldn’t cripple our capacity. The Japanese tried and failed. The fact that those factories existed after the war and needed other use led directly to the us economic hegemony after the war.

That has very little to do with the fact that the US is a republic, and not some totalitarian or authoritarian state. If the Germans’ factories weren’t smithereens they would have had a leg up on manufacturing production. Since because, you know, they had more capacity before the war. They just didn’t as the war progressed and they certainly didn’t after. Put modern day china’s government in America in 1946 - single party power with authoritarianism and no individual rights - and it’s highly unlikely you see a different result. You’d almost certainly see that polity exert hegemony militarily, diplomatically, and economically. Because the manufacturing base was untouched and everyone else’s was touched in a bad way. And add in all the geographic advantages.

Anyway, we can disagree on this.