Not an empire then? Ok. I'll stick to the empire thing. Nazi Germany was an Empire? because they called themselves the third reich? (as reich meaning realm or empire) at the most they were a project of an empire. So you agree there were empires, lots of them, but now, as in RIGHT now, no empire?
Let's agree to disagree then...
Nazi Germany was an Empire, because the term refers to a form of government and state structure, Nazi Germany, although it had no emperor, had an equally powerful figure as "Führer", and tried by all means will return a quasi-feudal system but with greater freedom economy.
The United States is not an empire, it is a federal constitutional republic. If you mean that the United States is the first world power and the dominant power, I give you the reason, in the bad and in the good that this implies.