This is our empire. Not so great as far as empires go but typically measured in military pluses and minuses as most empires were. People usually think of the later British Empire whenever they say the word empire. A romanticized empire which continued to exist past the military conquest stage in its creation to form a corporate commonwealth that exploited resources and labor and exported culture and language with the military relegated to a policing role. Bag pipes and cricket "Eh wot" - the sun never sets on the British Empire and all that?
Well mostly! We never use the word colony anymore and the sun did set on the British Empire.
What would an American Empire mean? Well the military stage is certainly there but would there be anything else? Or would we be creating the first Un-empire? A sort of reverse empire where we pay the costs of our troops in their country and extend financial aid to the supposed 'colony' (that we promise will never be a real colony) and so forth. An un-empire where our colonies exploit us through military aid and foreign bases on their soil that we pay them for etc.
This is not your father's empire, by any definition. We create enemies not friends, support corrupt quisling governments rejected by the population and as we see in Afghanistan, we have no solution for the situation except to leave but we can't leave because as yet the only thing that we have accomplished is that the population hates us for our military intervention.
The American Un-empire - a reverse colonization/exploitation where we expend treasure rather than gain treasure.
America's empire costs us men and money and doesn't accomplish anything (at least not for America) except achieve a destabilization and polarization of the world which continues to worsen.
Was the regional and cultural destabilization worth it?
Endless war is a war that can never be won. Forever war is an acknowledgement of a continuing failure and a reckoning of costs in the lives being lost needs to be made. Leaders and allies may spout their rationales for perpetuating an endless expenditure of American lives and money but we all see that is not accomplishing anything for us or the world.
Endless war is a lousy way to run an empire.