“And, what lands have we conquered and ruled over lo these hundreds of years now?”
Is that a trick question? It depends on who you ask.
Some Southerners might answer, Georgia or Alabama.
Some Hawiians might answer, Hawaii.
Some Mexicans might answer, the Southwest US.
Some American Indians might answer, Montana.
Some Puerto Ricans might answer, Puerto Rico.
Some Cubans might answer, Guantanamo Bay.
Whether you think you are ‘ruled-over’ depends on whether you agree with the aims of the current government.
And more directlly, can a great nation only be called an Empire if they are out colonizing other lands? I think the word empire can be used to describe a great and powerful nation.
In that case, we've been an empire since at least when? 1803, when Jefferson bought the Louisiana territory? 1783, when we got everything up to the Mississippi? 1775, when we tried to conquer Canada?
I'm not trying to argue with you, but would like to point out to the troops that in 19th century America, it was Democrats like Jefferson, Jackson, and Polk -- who tended towards state's rights, limited government, and strict construction -- who were most passionately expansionist and in one sense at least, imperialist.
A lot of the talk of our lost Republic relates to what Jefferson and Jackson did -- the "Revolutions" of 1800 and 1828 -- more than to what the founders may have intended.
In other words, the radical state's rights view wasn't Washington's, or Hamilton's or Adams's, but something the victorious Jeffersonians and Jacksonians imposed on the Constitution and the country.
So the very premises of the original question may be shaky.