I think the U.S. 'Empire' represents a new kind of entity. The Romans directly taxed their 'provinces'. This was a good source of revenue for them. We conversely make quite a few investments in our 'provinces' (Marshall Plan, etc...). We do not tax them directly. They are free to determine their own form of governance, but if they turn their backs on democracy, we can turn our backs on them. Basically, World War II ended with the complete conquering of Europe. The west, called 'English' by Germans, conquered Western Europe. The east, called 'Mongols' by Germans, conquered Eastern Europe. During the Cold War that division was crystal clear. Which form of empire worked the best was determined when the west won the Cold War. Many former Eastern conquered nations, quickly joined the west and NATO. I think it was fare to call the Eastern Europe Nations conquered lands as part of the Eastern 'Mongol' Empire. The word empire is not accurately applied to the Western nations that were conquered by the Western 'English'. We may need a new word eventually.
I think the word you are looking for exists already and it’s ‘Globalization’. The United States, the world’s most able nation, does not even remotely resemble an ‘Empire’ with one exception, its incredible ability. I recently read a book writen in the 1950s which contained an interesting categorization of politically minded people:
By this measure, the voice that names the United States an ‘Empire’ is a truly conservative voice. By this measure, the times we live in are both liberal and revolutionary. Certain enhancements in communications technologies, born of free and open societies, have created new actors, a new stage and entirely new behavior, aka ‘Globalization’. The first actors were American but we are not necessarily the most comfortable with it. There is no guarantee that globalization will indefinitely drive our success and by no means are Americans in control of it. There are societies with infrastructures better prepared than are own to adopt and succeed with the new tools of globalization. These future successes will not be dictated by a central authority in any imperial way. The fact is everyone is welcome on this new stage; it is of no consequence who built it.
Technically speaking, the real architects of globalization were not American, but philosophers who inspired Americans to behave in revolutionary ways. I believe many Americans take for granted how revolutionary our lives still are and how much our nation has changed in so short a time. We as a society are often dumbstruck with our own success and successes inspired by us. That said, not every step has been a step forward and a lot of blood has been spilt along the way. If one were to simply look at American falters I’d not be surprised that they might use the following phrases to blaspheme the Untied States and its leadership… its an Empire, because empire is historically familiar… its an Empire, because it is the most able nation on earth… its an Empire, because it is widely emulated… its an Empire, because it regularly engages in war…
The United States is not an ‘Empire’ because it is not in control of society nor does it seek to control society, but instead fights to eliminate arbitrary control over society. The United States is defined as anti-imperialist by its constitution and remains so to this day.