Secession is not conducive to imperialism, no. But I’d ask what’s so important about international prestige and giant armies? What has it gotten us, except ever more and more enemies and more burdens?
I would submit that there will always be a nation on earth that will seek to move things in the direction of their world view.
Hegemony is with us, and always will be. So the real question is, do we wish to relinquish being the world's hegemon? And if we do, then are we willing to accept the reality that another nation will take our place? Is Russia, China, Islam, or a number of other nations or ideologies that will form a federation going to be acceptable to us, as the world's new Hegemon?
Imperialism is an insult that is often levied against the United States, and I can loosely see a reason for it. In the pure sense, it's a rather flimsey charge to make. The United States doesn't attack nations who disagree with it's world view, unless they venture outside certain parameters. Allow your neighbors to live in peace, we won't bother you. Allow free passage on the oceans, and we won't bother you. Allow groups within your borders to plot against the United States and carry out attacks on it or it's allies, and sparks will fly. And they will fly, because we have the ability to respond anywhere on planet earth, and we are not going to allow other nations to prevent our presence anywhere on earth, or threaten us on our home soil.
Right now China is taking a massive bite out of the South China Sea. It's being so agressive in the region, that it won't even allow unarmed U. S. ships to operate in safety there.
Okay, so what do we do about that? Do we warn our ships not to traverse those waters? Do we back down as China makes more and more claims and demands? Do we simply withdraw from the world stage, and become an isolationist nation? That's where this all leads. In short order our citizens can't take world cruises. Sound like something you want to sign on to?
What has it gotten us? For the better part of the last century, we have been able to go anywhere on the high seas we wanted to. We have been relatively safe at home. Our allies have been assured that we have their back. We have been seen as the world's preeminent global power. Yes that made us a target, but it also made us unacceptable as an enemy. China is now willing to see us as an enemy. That should tell you something.
Read this article.
Red Flag Over the Atlantic - China is Angling to Take Over a U.S. Airbase in the Azores.
China is taking moves on two major oceans, that are directly tied to choking U. S. Naval passage. With this being the new reality, you still come here to ponder why the U. S. has to be the world's preeminent power.
The answer is, when it isn't the world's imperial power, as you reference it, someone else will be. And when we don't have the armed forces to stop them, there will be no going back.
That imperial power will dictate to us, and it will truly be an imperial power, willing to dictate to us on matters we never dictated to others about. Our armed forces once small enough, will not be allowed to rearm. That will be dictated by someone else.
We live in a very small world these days. The days of our Founding Fathers are not these days. A threat on the other side of the planet, is a very real threat at home.
We have only two choices.
1. We are willing to live with a bully on the block who can bloody our nose at will, and we have to go running home to mommy... or...
2. We wake up and restore our Navy to it's full strength, and kick the snot out of any bully that dares raise it's head to challenge us on the global playground.
Those are the facts.