There are many strange things in the world. But little is stranger then the existence of Nations. Not the land or the peoples themselves, no. There are individuals all over the world who are the very physical embodiment of the nation from which they take their names. These individuals or 'Nations' looks like normal humans but can live so very much longer. Nations are drawn to each other, what they do upon meeting another like them varies greatly. Some seek allies, other trade partners, but others still come only to conquer. These Nations are dangerous. Because Nations that are skilled at conquering become Empires.
There is something very important to remember about empires, they drink the blood of the lands they conquer in the form of goods and slaves.
But there is a secret about Empires that only other Nations know: Empires drink blood.
Literally.
Empires drink the blood of nations they conquer. Its binds Nations to them and greatly hinders the ability to rebel. Empires are forever thirsty for more.
Because of this there is very little more dangerous than Empires. All have heard of the Roman Empire and its other domination of the Mediterranean and much of Europe. Ottoman, Russian, Spanish, and Britannia all still send chills down certain Nations backs when mentioned. But a fact about Empires is that they fall, some harder than others. Some slowly decline, others vanish in a flash. If an Empire is lucky, it becomes a Nation again instead of vanishing.
If an Empire becomes a Nation again, it no longer has an unending thirst for Nations blood. It becomes relatively safe for other Nations to be around them again. Life goes on.
So...
Where does this leave the modern day Empire-in-all-but-name America?