"You're going back to World War II as your model. We were not so interested in empire then."

America is now more interested in empire?
Doesn't make much sense to me. But I would say we were a bit more interested in breaking up empires back at that time- the French and Britsh empires mostly, but of course we weren't very happy about the Japanese or Russian empire, either.

Presently, we don't seem to care much about the Chinese empire- nor do we even bother to call the taking over Tibet as building a empire [for some reason]. And I suppose Syria continued attempt to regain Lebannon doesn't count in this regard- is Lebanon too insignificant? Or perhaps because Iran has only heavily armed group in Lebanon and has the stated purpose to destroy Israel, so perhaps there is confusion over whether it's Syria or Iran that is the engaged in the empire building and of course whether nuking a country could be strictly classified as building an empire.
And in general we seem to think building the EU into a kind empire is a good idea, and AU is something we also consider as a favorable direction.

Now, if you mean the states of the United States become more controlled by the federal govt, I can see what you mean- but it's strange use of the term empire.

And if we were more interested in empire [assuming we had any talent in this] that would mean we would be acquiring some new land somewhere, wouldn't it? Couldn't we at least make Puerto Rico a state of the US- wouldn't that show at least a meager interest in empire? Afterall we did manage to add Hawaii shortly after WWII.

And if you are twisting the definition of empire to mean some kind of economic involvement between states, then I think we also have to look at what other countries such as China and India are doing. Chinese interests are all over Latin America [not to mention the port in LA, CA with their chinese trucks all over the freeways]. Nor are countries such countries such Mexico and Brazil shy about getting broader economic involvement in other countries.

So, I don't think it's accurate to say that America is growing a empire, it's more of a matter concerning the French empire- which is long lost- and the recently lost Soviet empire that is the actual concern. Therefore the French and ex-Soviets share a common gripe about losing their empires- but that doesn't translate to America growing an empire.