Its a metaphor, the purpose of which is to point out that Empires are Bad things that freedom loving Americans dont like.
You might want to recall such useful historical tidbits like:
To sum up: Empire=Bad
I hope that clears things up for you.
You are attempting to committ revisionism of the lowest order, comparing a potential American empire with the Nazis and the Spanish is pretty silly dont you think.
There is the term called "moral relativism" that you should really investigate.
We are better than them.
ps - What happened in the wake of the British Empire? I say look to Africa for your answer - they are MUCH better off today dont you think?
LOL
And now we must save the middle East from the corrupt, facist, despotic tyrannies, that have caused so much human suffering.
We don't need an American empire, we need to finish what our founding fathers started, and make freedom, liberty, and justice for all, possible for the whole world.