An Empire is a state where a title owner has kings swearing fealty to them in much the same way that others may swear fealty to kings. If the US were to form a monarchy, it would quickly follow suit that many other nations with kings, such as Saudi Arabia, would likely vassalize under it.
The ties between said nations would become greater under a monarchy. But yes in some respects the US already has many vassals. The difference between an Imperial Republic and an Imperial Monarchy, is that the vassals would swear fealty to the Monarch, not the United States.
An Empire is a state where a title owner has kings swearing fealty to them in much the same way that others may swear fealty to kings. If the US were to form a monarchy, it would quickly follow suit that many other nations with kings, such as Saudi Arabia, would likely vassalize under it.
The ties between said nations would become greater under a monarchy. But yes in some respects the US already has many vassals. The difference between an Imperial Republic and an Imperial Monarchy, is that the vassals would swear fealty to the Monarch, not the United States.