This is a thesis that could use far more development than I can give it at the moment, but I hope I can lay it out clearly enough that to generate some interesting discussion and perhaps revisit it later.
It’s frequently complained that the US is in danger of becoming a global empire. Traditionally one elaborates on this by quoting Washington’s farewell address if one is of the right, and by citing the evils of colonialism if one is of the left.
I’d like to suggest that the imperial horse has pretty much left the stable a long time ago. The US has been a global empire since World War II, and since the collapse of the Soviet Union has been the sole global power. Although, like the later Roman Republic, the US has not actually taken direct political control over countries beyond its traditional borders (nor does it collect tribute from abroad) it has a sphere of influence covering much of the known world and is repeatedly involved in exerting pressure or deploying force to ensure regional conflicts do not spin out of control.
This in itself is perhaps not a terribly unusual thesis.