>>571210Every great empire experiences a period in which they are so powerful that no one can compete, and so there are no real wars fought. Objectively speaking this phenomenon has never extended to the global scale as it does now, but if you grade on a curve there have been more impressive states in the past.
What is special about America is that we have a largely monolithic culture spread over such a large area. Only China (and Russia to an extent) have absorbed such vast amounts of land into their cultural sphere. And China does it by virtue of their dense population of Han Chinese in the west being large enough to control the east. We have largely the same culture everywhere.
In time our global relevance will decrease. But as long as the union survives, the US will survive as an impressive North American empire. There's simply no way to dent our influence on our own continent.