All comparisons between America's current place in the world and anything legitimately called an empire in the past reveal ignorance and confusion about any reasonable meaning of the concept empire, especially the comparison with the Roman Empire.
I think Henry Miller has had huge influence not because he wrote about sex, but because the memoir or the nonfiction novel has become such a monumental force in American publishing, if not in literature.
A modern civilization is only possible when it is accepted that singular beings exist and express themselves freely.