Well, yes, this is true. However, there is a problem in that empires built up through force have to maintain themselves through force. That's the trap that the U.S. finds itself in right now. We've built up on blood and conquest - not just on this continent, but it's practically a world-wide phenomenon with the U.S. military scattered all over the planet.
Yet we also want to pass ourselves off as this "white knight" who only wants to feed the starving billions, save women and children from tyrants, etc. It's all about spreading "freedom" around the world, or so we want everyone to think.
We want everyone to think that America is this paragon of virtue which holds the moral high ground above the rest of the world. We want the oppressed peoples (both in America and around the world) to think that we've all reformed and that we're all just a bunch of egalitarian "nice guys," although the opposition to this philosophy think that this is a sign that Americans have grown soft and weak. They think that we need to toughen up and be strong - just as we were under Andrew Jackson.
And then there are those on the other side of the spectrum which are starting to grow impatient with the well-meaning yet mealy-mouthed moderate liberals whom are also viewed as too soft and weak by those further to the left. That's where all this dreaded "socialism" is coming from.
As a result, those at both ends of the spectrum are getting stronger, while those in the middle are getting weaker.
The USA sits astride world trade routes with virtually
infinite power and resources. There is whitewash,
there are true believers, but it is about power wealth
and control. The world revolves around the US,
economically and culturally. Just a fact.
Nobody cares to just walk away from such.
I personally think the world is better for it being
so, while understanding full well that there is
fear and resentment, inequity, etc.
As for empires and force, of course. But I was
not referring to empires, but every nation on earth.
Territory seized by force from prior inhabitants,
for reasons of wealth and expansion.
The USA has its own story, but so does every other who
did the same, with such local variations as there were.